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SELECTIONS FROM THE MEDIA CENTER

~ BOOK

The Mulch Book: A Complete Guide forGardeners--Stu Campbell," revised andupdated by Donna Moore. StoreyCommunications, Inc., SchoolhouseRoad, Pownal, VT 05261. 1991. Illus.120 p. Paper. $8.95 USA/S11.95Canada.

Plants are mulched for a variety of rea-sons, from eliminating weeding to con-serving water in the garden or landscape.The Mulch Book thoroughly covers themany practical aspects of mulching veg-etables, fruits, and landscape plants. Thisbook should be quite useful as a referencebook for agricultural extension agents,master gardeners, and gardening enthu-siasts. The book would also be useful asa resource for horticulture instructors atvocational schools or universities. Thisbook, however, would be inappropriateas a student textbook because of its nar-row subject matter and lack of recentreferences.

The book has nine chapters, an epi-logue, a handy quick-reference chartabout different types of mulch materials,a list of references, a list of businesses thatsell mulching supplies, and an index. Af-ter the introduction (Chapter l), the ben-efits (Chapter 2) and drawbacks (Chapter3) of mulching are discussed. In these twochapters, the authors describe the practi-cal reasons for and against using mulch.In the chapter on drawbacks to mulch-ing, the authors get a bit carried awaywith describing arguments among garden-ing experts as to whether or not mulch-ing is beneficial. In Chapter 4, definitionsare provided for different types ofmulches. For example, terms such asfeeding mulch, green-growing mulch, anddust mulch are defined among others.Different types of mulches are describedalong with their inherent advantages andproblems in Chapter 5. A number of stan-dard mulches (straw, bark, plastic sheets,etc.) as well as novel materials (felt/tarpaper, oyster shells, pyrophyllite [calcineclay], etc.) are covered in this chapter. InChapter 6, tips for making the most ofmulch are presented. In the last threechapters of the book, the authors describehow to mulch vegetables, fruits, and land-scape plants. Mulching techniques aredescribed for a number of different veg-etables and fruits, although the specieslisted are not all inclusive. Mulching tech-niques for landscape plants (Chapter 9),however, are limited to only rhododen-

drons and azaleas, roses, bulbs, and ageneral description for trees and shrubs.

The quality of this book is reasonablygood. The book is logically organized andcontains 26 hand-drawn illustrations thatdo a fair job of conveying the ideas de-scribed by the authors. They also use sub-tle humor in various places to emphasizetheir points. The quick-reference chart onmulching materials is excellent, and thelist of companies for mulching suppliesis also good. Weaknesses of this book in-clude a lack of scientific explanations forplant response to mulching, inaccuratedefinitions or explanations of some terms,and a limited number of recent referencescited in the bibliography. With regard toreferences, only three out of the 28 citedwere published after 1980.

In summary, The Mulch Book is easyto read and provides some unique ideasabout mulching different types of plants.Although 1 would not recommend thisbook for use in college courses, it is agood general reference book for extensionagents, gardening professionals, and hob-byists.--ROBERT R. TRIPEPI, PlantScience Division, University of Idaho,Moscow, ID 83843. ¯

~ BOOK

Protected Cultivation in the Mediterrane-an Climate--A manual prepared by theHorticultural Crops Group of the FAOPlant Production and Protection Divi-sion. Distributed by Unipub, 4611-FAssembly Drive, Lanham, MD 20706-4391. 1990.97 illus. 313 p. Softcover.$45.00

The book has been prepared on the ba-sis of the scientific contributions made byI l scientists from different countries: A.Nisen (Belgium), M. Grafiadellis(Greece), R. Jmenez (Spain), G. La fa (Italy), P.F. Martinez-Garcia (Spain),A. Monteiro (Portugal), H. Verlodt(France), O. de Villele (France), C.H. Zabeltitz (Germany), and 1.Cl. Denis(FAO), under the coordination of W.O.Baudolin (FAO).

The subject has been limited to a par-ticular climatological environment de-fined as the Mediterranean climate, whichmainly prevails in countries surroundingthe Mediterranean Sea, but is also presentin other regions and continents. The Med-

iterranean climate seems particularly suit-ed to benefit from the techniques ofprotected cultivation, both in winter,when the cultivation of heat-requiringplants is limited by the low temperatureat night, and in summer, when the pro-tection reduces the evapotranspiration ofplants and the effects of the wind.

The order of topics presented in thebook is as follows: introduction, produc-tion conditions; structures, materials, andproduction equipment; environmentalcontrol; production means and tech-niques; crop production; and economicaspects.

A brief introduction (8 p.) explains thedevelopment of protected cultivation inthe Mediterranean area, supplying statis-tical information on protected areas indifferent countries. Next is a short de-scription of physical (climate, soil, water)and socioeconomics factors (20 p.). Thethird chapter (77 p.) describes and dis-cusses the materials and the structuresused for greenhouses and tunnels, includ-ing mulching materials, windbreaks, andhotbeds. The following two chapters (40p. each) report the main problems of en-vironmental control (heating and coolingof greenhouses, light, humidity, andCO2) and production means and tech-niques (soils, substrates, fertilization, ir-rigation, mechanization, weeds, pest, anddisease control).

The central section (98 p.) is devotedto a survey of cultivation of the most im-portant crops: tomato, pepper, muskmel-on, eggplant, cucumber, summer squash,strawberry, lettuce, French bean,watermelon, carnation, rose, pot plants,grape-vine, banana, pineapple, andpapaya. The main characteristics of eachcrop are summarized: anatomy (growinghabit, roots, leaves, flowers, and fruits),ecologic requirements (temperature, hu-midity, light, etc.), and varieties. More-over, cultural practices for protectedcultivation (cultivation period, growingcycles, crop sequence, propagation, plant-ing, fertilization, irrigation, pests, anddiseases) and economic aspects aredescribed. This section is a description ofadopted techniques, more than a crop-ping handbook.

The last chapter (22 p.) is devoted the economic aspects of tomato, pepper,and egg-plant, protected under pltastic, inthe mentioned countries. Actual prices,labor costs, and the main factors ofproduction differ to a large extent from

52 ̄ J. Nat. Resour. Life Sci. Educ., Vol. 22, no. 1, 1993

one country to another, and the tech-niques used vary greatly. Therefore, thissection is only a model of economic evalu-ation, and it emphasizes the differencesbetween countries.

On the whole, the book describes themost important elements of protected cul-tivation in the Mediterranean region: thebasic principles, the results of experimentscarried on so far, the current trend insome advanced fields and the present andfuture possibilities, and the limits of thetechniques used in other countries, whereprotected cultivations are widespread orin progress.

A selected bibliography (46 items)offers a general list of works that providea wider knowledge and a deeper under-standing of protected cultivation.--MARINO PERELLI, Via Puccini 11,1-30034, Mira VE, Italy. ¯

~ SOFTWARE

W.E.E.D.S. (Western Expert Education-al Diagnostic System)--Richard R.Old, Robert T. Dobbins, Patricia J.Hine, Robert H. Callihan, and Fran-cis E. Northam. Weed Diagnostic Lab,Department of Plant, Soil and En-tomological Sciences, University ofIdaho, Moscow, ID 83843-4196. 1990.Retail: $79.99; Educational: $59.99plus $5.00 shipping and handling.

WEEDS is a computer program forweed identification with custom menusand data base for Weeds of the West. Thepackage includes the program on diskette,a 110-page manual of terminology withshort definitions and line drawings ofplant parts, and the 630-page, color-illustrated Weeds of the West. It requiresa computer with DOS 3.0, 384K RAM,100O7o IBM compatability, with hard diskrecommended.

The program enables users to select themost obvious characteristics of theunknown plant specimen, to narrowdown the possibilities from those illustrat-ed in Weeds of the West, to a handful ofchoices that can be quickly looked at todetermine a match.

To illustrate the steps in identifyinghenbit, for example, the choices might be:

1. Plant non-grass-like (304 remainingpossibilities)

2. Flower purple (79 possibilities)3. Flower strongly irregular (22 possi-

bilities)4. Stem cross-section square (3 possi-

bilities)

At any step, the user can use a functionkey to call up a list of remaining possi-bilities to determine when they want to

turn to the illustrations in Weeds of theWest.

The program has some important limi-tations. In its present form, it is intimatelytied to Weeds of the West. To be widelyapplicable, future versions would requirethe addition of more weed species, andcross-referencing with other weed identifi-cation guides.

Another limitation of this program,and of most plant identification keys, isthe need for mature plant specimens withflowers, fruits, and roots. Users will notfind this program useful for identifyingseedlings and many juvenile plants.

The program sometimes allows for var-iance in biotype differences. For exam-ple, either purple or red-purple can bechosen to describe henbit flower color.However, should the user choose flowerwidth as a character, and select 2 mm (theexact width this reviewer measured on avigorous Kansas specimen), henbit wouldbe eliminated from the possibilities, as theselection of 3 mm is required. This illus-trates a weakness of the program.

Users should be cautioned to stick withsimple, obvious plant characters when-ever possible, and be prepared to restartthe selection sequence if they do not meetwith success. A function key can be usedto backtrack, and "un-do" the last selec-tion only. The WEEDS tutorial, presentlyat the end of the manual, should be earlyin the introduction, before the user getsbogged down in function keydescriptions.

The WEEDS program does not requirea taxonomy background, but does requirewillingness to learn plant terminology,and considerable practice. Explanationsand drawings in the manual, interspersedwith keyboard activity, should help theattention span of users.

Weeds of the West, a publication of theWestern Society of Weed Science, is oneof the most attractive picture identifica-tion books this reviewer has seen. It is co-authored by six extension weed scientistsand an herbarium manager. For each spe-cies described, there is a full-page aspectphoto on the left-hand page, facing sever-al paragraphs of descriptive text and twosmaller photos with more detail such asimmature plants, seeds, bulbs, or othercharacteristics of diagnostic value, on theright-hand page, all on glossy, high qual-ity paper. The book is a joy to pagethrough "just for fun." It can be pur-chased separately for $19.50, postagepaid, from Cooperative Extension Serv-ice, Ag Bulletin Room, P.O. Box 3313,University of Wyoming, Laramie, WY82071-3313. Make checks payable to AgBulletin Room.

There are a few poor photo choices inWeeds of the West. For example, the de-

tail of longspine sandbur spikes addsnothing to what is shown in the largerphoto, and the photo of the immatureplant is not very helpful. This reviewerwould have preferred a close-up of theseedling plant, which is quite distinctive,with or without its sandbur seed still at-tached.

How complete is the book, and is it ofinterest east of the Rockies? It containsroughly 364 entries, so clearly its scopeis limited. For example, it contains 64 ofthe 74 weed species taught to 4-H youthin Kansas, omitting mostly species withdistribution toward the east. However,this book should be useful at least acrossthe Midwest. It could be a fine compan-ion for anyone traveling west of the Mis-sissippi River. But, don’t expect to carryit on long hikes, as it weighs 3 pounds!

The authors of WEEDS and of Weedsof the West should be commended fortheir fine work. The long-term success ofthe computer program will depend on theauthors’ follow-up with refinements andadaptations to areas beyond the westernstates. The concept of using computertechnology to relieve the drudgery ofdichotomous keys is a sound and welcomeone. It still requires dedicated effort andwillingness to master botanical terms forsuccessful plant identification.--DAVIDL. REGEHR, Department of Agronomy,Kansas State University, Manhattan, KS66506. ̄

VIDEO

Grass Identification--l--Billy BobMcMullan and Ernie Eckert. CreativeEducational Video, P.O. Box 65265,Lubbock, TX 79464. 1991. 34 min.$79.95.

Instruction of plant identification, es=pecially grass species identification, ismost effective when live plant material isused in a field lab, or greenhouse setting.Due to various constraints, however, in-structors often employ alternative teach-ing aids, namely dry mounts, photomounts, illustrated keys, or slides. Whileconvenient, these techniques are often lesseffective than using live plants. A new al-ternative to teaching the identifiction ofrange and pasture grasses, using educa-tional videotapes, has been developed byBilly Bob McMullan and Ernie Eckert,both experienced in coaching Texas FFAchampion range and pasture judgingteams. This review examines the firstvideo in the two-part series.

J. Nat. Resour. Life Sci. Educ., Vol. 22, no. 1, 1993 * 53

The grasses (17 species in this video) areviewed against a dark backdrop in thefield, and descriptions of the plants aremade on-site by McMullan and Eckert ina casual, seemingly unrehearsed, almostconversational fashion. At times descrip-tions are stumbled over, repeated exces-sively, and irritatingly nondescriptive.Terminology to describe parts of the grassplant is often improperly used, or notused at all. For example, the inflorescenceof one species is described as looking likethe crankshaft that one would pull fromone’s car. The leaf blade is referred to asthe "leaf," and the sheath is described asbeing the "stem." Auricles are improper-ly called a "split ligule," or "horns."Misuse of morphological terminology,and use of casual descriptions of parts ofthe grass plant, severely limits the useful-ness of this video for college-level teach-ing. The casual descriptions and analogiesused in characterizing these grasses mightwork well for FFA teams, the most obvi-ous target audience for this video, butwould be inappropriate for higher-leveleducation. In any case, the video wouldbe most effective if used in conjunctionwith other identification aids, like drymounts or an illustrated key.

From an editing standpoint, this videopossesses a number of flaws. Graphics aresuperimposed over the visual of the grassto give the common and scientific names,as well as to emphasize descriptive charac-teristics verbalized by Eckert and McMul-lan. While potentially helpful to someonetaking notes, they occasionally coverparts of the plant being simultaneouslydescribed. Also, a few errors were missedduring editing, including the use of"course" to describe the texture of onespecies, and the use of "pedestal" insteadof the proper term, pedicel. Perhaps mostirritating, however, is that references aremade to other similar-looking plants thateither never appear in the video, or ap-pear a number of minutes later in thetape--a problem that simple editing couldhave prevented. For example, switchgrass(Panicum virgatum L.) was neverdescribed in this video, but during thedescription of big bluestem (Andropogongerardii Vitm.) it is said to resemble thepreviously described switchgrass. Annu-al three-awn (Aristida dichotoma Michx.)is the first grass examined in the video,and is said to closely resemble perennialthree-awn (Aristida longiseta Steud.). Itwould be logical for a description ofperennial three-awn to follow, but thisspecies appears about 30 min later, withthe reminder that it resembles annualthree-awn. A number of other such sim-ple editing errors occur in the video.

This video would be useful for instruct-ing its target audience--FFA teams--butwould be of limited usefulness for uni-

versity-level instruction. Further, therange of species featured in the reviewedtape indicate also that this two-part ser-ies is intended for audiences in the south-central USA, particularly Texas, Oklaho-ma, New Mexico, and parts of Kansasand Arizona.--ANTHONY J. KOSKI,Department of Horticulture, ColoradoState University, Ft. Collins, CO80523. ̄

i~ BOOK

New Technologies and the Future ofFood and Nutrition --Edited by G.E.Gaull and R.A. Goldberg. Proceedings

of the First Ceres Conference, Wil-liamsburg, VA, October 1989. JohnWiley & Sons, 605 Third Ave., NewYork, NY 10158-0012. 1991. 174 p.$50. Hardback.

A group of leaders in science, business,industry and government were broughttogether at this conference to identify keyscientific, socioeconomic, and political is-sues and questions affecting the food in-dustry as it enters the 21st century. Thepresentations in the book are organizedinto six parts:

I. Demographics, Agriculture, and theFood Industry

2. The Biological Revolution, Agricul-ture, and the Food Industry

3. The Future of Nutrition4. Food, Nutrition, and Health: The

Role of Government5. The Forces Affecting Food: Implica-

tions for Industry6. Economic Prediction

The Biographies of Contributors and anindex completes the organization of thebook. Each part opens with an abstract,and about half the chapters have a list ofseveral background references. The con-tributors include four Noble Laureates,Secretaries of Agriculture and of Healthand Human Service, Commissioner of theFood and Drug Administration, and theCEO of Kraft General Food.

Biotechnology is expected to be themost important scientific tool to affectthe food economy in the history of man-kind. At the same time major political,social, economic, environmental, and in-formational changes are occurring. Theeditors provide an analysis of the develop-ments that are shaping the food sector ofthe future and identify issues for privateand public policy makers. They leave toa future conference the questions of howthese issues are best solved and whoshould take the lead.

The book should be a very good refer-ence for policy makers, planners, andteachers of broad interdisciplinarycourses. Scientific advances and changesin our global economy will create numer-ous opportunities for new jobs and newways of operating in the future of foodand nutrition. New technology ’will notonly improve the production of food byagriculture and the food processing fac-tories, but it will reduce the environmen-tal impact of agriculture and foodprocessing. In addition, the quality offood will be improved by higher and/orbetter nutrient levels and lower levels ofantiquality factors. As more and moreeconomies around the globe becomemarket-oriented, new business organiza-tions will be created to take advantage ofthem.

In his conclusions, Goldberg predictsthat technology wil change half theworld’s economy, affect the nutrition andhealth of populations, and effect the eco-nomic development and linkages betweenand within agribusiness and the rest of theglobal economy. What an exciting timeto be in the agriculture/food business!--MAURICE H. FRERE, U.S..Depart-ment of Agriculture, AgricultureResearch Service, Watkinsvill’e, GA30677. ¯

~ BOOK

Soils of the Tropics, Properties andAppraisaI--Armand Van Wambeke.McGraw-Hill Book Co., 11 W 19th St.,New York, NY 10011. 1992. Illus. 343p. with appendices and glossary. Hard-cover. $49.95.

There are Oxisols in the tropics as onewould expect. But there are also Ultisols,Alfisols, Vertisols, Andisols, lnceptisols,Spodosols, Aridisols, Mollisols, and En-tisols. Aridisols are on only 4.1 oT0 fewertropical hectars than are Oxisols. Alfisols,the soils of the cool humid eastern decid-uous forest, are only 2.2°7o less in abun-dance than are Aridisols. This issomewhat surprising to me, because I’venever been in the tropics. The term con-jures up an image of the hot, humid rainforest--the images we associate with thatof the Amazon jungle in recent times aswe worry about our environment as thebiodiversity of that region is slowly wipedout. Van Wambeke begins his book bydefining what the term tropics means inthe context of this book: "The climaticattributes of the tropical area derive fromits geographic location between latitudes23027’ North and South."


In this region the sun is directly over-head every day at noon, the day lengthsremain the same throughout the year, andthere are no seasons as we in temperateregions are accustomed to thinking ofthem. But there are "summer" rains inmost places. So, how do we get Aridisolsthere? It’s because large desert areas ex-ist within the tropical latitudes. They get"winter" rains too, but apparently notvery much. The actual distribution ofsoils is a function of all the factors of soilformation, as in any area. Van Wambekecarefully discusses these factors. He pre-sents excellent diagrams that suggest theinteraction of temperature regimes, mois-ture regimes, and landscapes in the pedo-genic process, and the resultant sets of soilproperties that lead to placement in a SoilOrder.

This is a book for upper division classesand a reference for professionals in thefield. It is a good one, I believe. It coversa lot of what I include in a course, SoilGenesis and Classification, in addition toenough edaphology to keep the text rele-vant to the commonplace problems as-sociated with supplying nutrients andwater to plants. Also, soil erosion and theeffect the tropical climate has on it is con-sidered several places in the book.

Van Wambeke has organized his bookinto two parts. The first (Part I) describesthe "Tropical Soil Environment." Thisincludes chapters on soil climate, parentmaterials, vegetation, organic matter, andcrops. It also considers termites andmesofauna as they affect soil formation.A chapter on the formation of "Diagnos-tic Horizons" is included in this section.

"Soil climate is the only common at-tribute that all soils in the tropics share,and that separates them from soils of thetemperate regions." Radiation and airtemperature as they affect soil are dis-cussed, as are means to modify this ef-fect. The vertical zonation of vegetationcommon in all mountainous regions andthe effect of this on soil is profound intropical regions. Optimum temperaturesand altitudes for optimum crops com-monly grown are given in tables. One ofthese tables, incidentelly, is printed up-side down in the copy of the book I have.It is readable, but it looks a little strange.Soil moisture, rainfall patterns that varyin the extreme of intensity, and the rela-tionship of these to vegetation patternsand to soil erosion are discussed in somedetail.

Weathering, rock composition, andclay synthesis appear in the chapter thatdeals with parent materials. Weatheringgoes deep in the tropics and the presenceof "stone lines" attest to (i) ancient ex-posures of erosion surfaces later coveredor (ii) activities of termites in selectively

removing finer soil particles to the sur-face. A clear relationship exists betweensoil properties and continental platformsand orogenic belts. Ancient soils, dis-turbed by only the slow depletion of theages mantle the platforms, while sharplyyounger soils lie in the rift valleys of theorogenic belts. Litho and topo sequencesexist across all regions, as do color andweathering sequences. All are governedin one way or another by the geologichistory--the normal weathering of themantle rock at the earth’s surface.

Soil, as we understand it, is biologicallyweathered. Biological weathering is ofnecessity associated with life processesthat mix organic substances with the soil.The nature of these organic substances iscontrolled by the environment, and inpart controls the soil environment. Thedynamic aspects of this association andits chemistry is specific for tropical soils.Rates of decomposition of the biomassproduced and the total biomass produceddiffer within tropical regions from therain forest through the desert areas. VanWambeke shows the annual biomass ofthe rain forest to be 10 Mg/ha per yeardry matter. Life span of leaves is 12 mo.They fall when the soil is dry--hence donot produce the weak organic solutionsto infiltrate and affect soil weathering.The leaves contain 23.5% of the nutrientsstored in the main forest. Since they fallon dry soil and are often lost to the soil,a net loss occurs. Conservation of thismatter is critical to fertility of tropicalsoils. But then the rain forest is "no morethan an enormous mass of weeds thatmust be removed before any resourcefulland use system can be implemented" (anovel way to refer to something many feelhas ultimate control over the ability of thehuman to survive on planet earth).

Savannahs and woodlands also exist intropical regions. Soils therein are not fardifferent from soils on savannahs andwoodlands elsewhere. Here, Van Wam-beke discusses the mode and rate of or-ganic matter accumulation in the soil. Healso concludes that "forest fallows" thatprotect the soil against high femperaturesand erosion and "grassland/woodlandfallows" rebuild organic matter levels andfertility in the soil, and are the most ef-fective low input means to do so.

The book includes a chapte.r that ismostly about termites. Termites in thetropics are significant in modifying soilproperties. Their biology, activities, andeffect on soil formation are discussed ina very interesting manner.

The chapter "Soil Horizon Forma-tion" really means diagnostic horizon for-mation. There is no reference to horizonsas we refer to them in soil morphology.There is a good discussion of the Som-

bric horizon--a horizon of whose originwe know little, except that it is associat-ed with tropical soils.

Part 2 of the book deals with the SoilOrders. It begins with a chapter to out-line the aims of the process of soil clas-sification. Soil moisture and temperatureregimes are discussed and keys tomoisture regimes and to Soil Orders (ex-cept Histosols) are presented. These keysapply to all soils, not just to those of thetropics.

The remainder of the book is devotedto a consideration of soils within each ofeight Soil Orders in tropical regions. Ox-isols (Ch. 7), Alfisols and Ultisols (Ch.8), Vertisols (Ch. 9), Andisols (Ch. Inceptisols (Ch. 11), Spodosols (Ch. 12),and Entisols (Ch. 13) are included. Soilsthat are within tropical regions (Table 6.1)but not discussed in detail are Aridisolsand Mollisols. Few soils that meet the or-ganic matter amounts necessary for themollic epipedon exist in the tropics (1%of the area). Aridisols are apparently notmuch different in the tropics than in otherregions. Sandy lands (Arenosols-FAO-Unesco-Psamments) occupy about 10%of the land in tropical regions. These arediscussed with the Entisols in Chapter 13.

The book contains two appendices.The first is a 22-page glossary of "soilscience" terms. These terms are not res-tricted to those used in communicatingabout tropical soils. The glossary also in-cludes a table of classification for clay-sized minerals and one that shows theconversion of S1 units to those that onecan understand. The second appendixconsists of 17 pedon descriptions withdata. Soils in the following subgroups areincluded:

Plinthic KandiudoxHumic Rhodic EutrustroxAnionic AcrustoxAcrustoxic Kandiustult (two of these)Plinthic KandiustultTypic Kandiustalf (two of these)Kandic PaleustalfRhodic PaleudalfEntic ChromustertTypic ChromustertTypic MelanudandHydric Pachic FluvudandAcrudoxic HydrudandFluventic UstropeptTropohumodIt has been 20 yr since the National

Academy of Sciences published "Soils ofthe Humid Tropics" 0972). Boundariesof soil groups have changed since then,and our knowledge base on tropical soilshas been greatly expanded. Van Wam-beke’s book has more pedology than does"Soils of the Humid Tropics," but it con-tains enough edaphology to retain con-tact with the major reason we study

J. Nat. Resour. Life Sci. Educ., Vol. 22, no. 1, 1993 ̄ 55

soils--that of producing crops. In 1980the International Rice Research Institute(IRRI) published Priorities for Alleviat-ing Soil-Related Constraints to FoodProduction in the Tropics. This has alsobeen a very useful book about tropicalsoils and their use. Van Wambeke’s bookprovides the firm pedologic base that the1RR1 and NSF books lacked. PhillipeDuchafour’s Ecological Atlas of Soils ofthe Worm (1978) included many tropicalsoils. It was, however, an attempt to con-sider soils in all major ecosystems, andwas not nearly so detailed as Soils of theTropics. In 1989 a series of papers werebound in a volume entitled Dynamics ofSoil Organic Matter in TropicalEcosystems. Van Wambeke refers tosome of the information in those papersin his book. Management of organic mat-ter is extremely critical in the moreweathered of tropical soils. This is ex-plained by Van Wambeke, but not in thedetail of the Dynamics papers.

Soils of the Tropics summarizes a lotof information about tropical soils. Ifound it to be interesting, and l will putit to use in a class on world soils I willsoon be teaching. It is not a text for theuninitiated, but for those well along in thematurity of thought process andknowledge of soil science--DAVID T.LEWIS, Department of Agronomy,University of Nebraska, Lincoln, NE68583-0914. ̄

~ BOOKAmerica’s Academic Future: A Report of

the Presidential Young InvestigatorColloquium on U.S. Engineering,Mathematics and Science Educationfor the Year 2010 and Beyond--National Science Foundation, Direc-torate for Education and HumanResources, 1800 G St., Rm. 1210,Washington, DC 20550. 1992. Publ.91-150. 41 p. Free. Paper.

This excellent report contains therecommendations of 53 young scientists,who met in November 1990, all recipientsof prestigious National Science Founda-tion Presidential Young InvestigatorAwards. Their recommendations are notreally much different from those in doz-ens of recent reports on the sad state ofU.S. science and technology education.The big difference is that this call forgreater emphasis on university teachingand service comes from young research-ers, who have all won a top award forresearch excellence.

An Executive Summary gives fivemajor points:

1. Encourage and reward teachingexcellence, instructional scholar-ship, and public service as well asresearch.

2. Increase substantially resources forinstructional innovation and curric-ulum renewal, especially for under-graduate education.

3. Assume primary responsibility forpublic understanding of science andtechnology, principally throughhigh quality precollege teacherpreparation and lower division un-dergraduate instruction.

4. Assure adequate career participa-tion in engineering, mathematics,and the sciences by all segments ofsociety, particularly careers as pre-college or college faculty.

5. Encourage the development ofdiscovery-oriented learning environ-ments and technology-based in-struction at all educational levels.

These five main recommendations are dis-tilled from the many more specific recom-mendations in each of the six panelreports.

The major thrust of the report was that"The tenure, promotion, and reward sys-tem is our greatest barrier to a better fu-ture. Tenure guidelines uniformly denotethat teaching, research, and service arethe criteria for tenure. It is our experience,however, that the road to tenure ismarked research, research, research."

The colloquium address by Charles M.Vest, President of the Massachusetts In-stitute of Technology, must have beenvery disappointing for the audience ofYoung Investigators. However, it neatlysummarizes the unrealistic and unbend-ing attitudes of most research universitiesthat the reforms mentioned in this reportare not needed. Vest praised Americanresearch universities as the best in theworld, noting that "I believe that researchis fundamental to our activities" eventhough "some may regard my view onthis matter to be hopelessly old fashionedor unrealistic." Vest also repeated thenow discredited NSF propaganda abouta massive "shortfall" of scientists and en-gineers by 2010. The 10 Apr. 1992 Sciencereported that the NSF message of a scien-tist shortfall in the near future "was one-sided and possibly a deliberate exaggera-tion" while the I May 1992 Sciencereported of a current glut of Ph.D. scien-tists and engineers, noting that a singleassistant professor position in computerscience attracted 1000 job applicants.

An epilogue to the report notes that thecolloquium’s greatest value may not bethat universities will heed its advice.

Rather, it provided a valuable way of"reinforcing commitments to teaching"for "a somewhat lonely group in the sensethat most return to environments wheremany of their colleagues subordinate theirteaching to research interests." How sadand ironic that the poor teaching environ-ments they return to are America’s topuniversities.--DAVlD R. HERSHEY,Department of Horticulture, Universityof Maryland, College Park, MD20742-5611. ̄

~ BOOKScale-up and Automation in Plant

Propagation--Edited by Indra K.Vasil. Academic Press, Sea HarborDr., Orlando, FL 32821. 1991. Illus.267 p. Hardcover. $105.00.

The premises upon which Scale-up andAutomation in Plant Propagation arebased are two: that regeneration of plantsfrom meristems, tissues, and cells is nowfeasible, but remains too expensive foruse with most transplant vegetables andfruit, spice, plantation, and forest species;and that it is probable that scale-up andautomation could reduce cost to 25g0 ofcurrent costs or less, thus bringing pro-duction of these commodities into therealm of practicality. Editor Vasil hasskillfully selected world leaders in the fieldof micropropagation to present chaptersthat describe the current state of micro-propagation, synthetic seed technology,automation of embryogenic and organo-genic systems, contamination and envi-ronmental control, and the use of newtechnologies such as bioreactors, machinevision, and robotics. Vasil eloquently elu-cidates the rationale and the essentialnature of scale-up and automation to fa-cilitate adoption of micropropagation ona much wider scale than current practice.He further points out that micropropa-gation is the first practical application ofbiotechnology and traces the history ofresearch to its successful application.

Current methods of commercialmicropropagation are thoroughly ad-dressed by authors Kurtz, Hartman, andChu, all of whom have many years ofpractical experience in commercializationof plant tissue culture, especiallymicropropagation on a large scale. Theynicely lay the foundation for subsequentchapters through use of excellent illustra-tions and by their description of the"stages" of the micropropagationprocess. Although the terms "Stage 0,""Stage 1," "Stage 11," and "Stage 11I"are described very well, it is unfortunate


that many of the other chapters could nothave followed this terminology in theirdiscussion. However, it is recognized thatthis book is a compilation of individualindependent contributions rather than thework of a single author and so this minorproblem is of minimal concern.

The chapter on synthetic seed technol-ogy is handled by individuals who are trueleaders in the field of this endeavor andnicely describes the state-of-the-art at thetime of writing this book. This chapterprovides a good review of the technolo-gy that has been developed along with anicely illustrated protocol for the specif-ic steps involved in somatic embryo for-mation and conversion to plants. As withseveral chapters in this book, the syntheticseed technology chapter clearly posesboth the pros and cons of this technolo-gy, including a good discussion of thephysiology involved in the variousproblems with synthetic seeds. This chap-ter deals in some detail with bioreactordevelopment as a component of mechani-zation of the process of synthetic seedsproduction and perhaps would have beena good lead-in chapter for the chapter onbioreactors as well as the chapters on con-trolled environments and use of roboticsin automated micropropagation. Theselatter chapters occur at a midpoint andnear the end of the book, creatingperhaps a less than desirable flow throughthe book.

The chapters on specific crop types(embryogenic forest trees, microtubers ofpotato, microbulbs of lilies, and automat-ed propagation of fruit trees) are all welldone and nicely illustrated. The chapterson microtuber and microbulb productionare especially interesting since they offerexcellent opportunities for "cottage in-dustry" development in rural areas ofboth developed and developing countries.The relatively low cost of set-up for thesesystems makes it especially attractive fordeveloping countries and represents agood possibility for rapid improvementof these crops and others that would lendthemselves to similar protocols in de-veloping countries.

This reviewer was particularly im-pressed by the chapters by Kozai ("Con-trolled Environments in Conventionaland Automated Micropropagation") andFujita and Kinase ("The Use of Robot-ics in Automated Plant Propagation")since these chapters address the heart ofthe concern for the future of scale-up andautomation in plant propagation. Kozai’sthesis is based on the concept of reduc-ing costs by removal of sugar and agarfrom the medium, increasing the pho-toautrophic ability of the developing ex-plant which includes increasing light andcarbon dioxide through a composition of

a flow-through system and the use of aliquid culture system that facilitatesmanipulations of the constituents of themedium. Of further futuristic interest, thechapter by Fujita and Kinase explores therationale for use of robots and explainsthe development of a prototype robot sys-tem along with a description of roboticsensors and cutters and some aspects ofa "second generation robot" that can cut,grip and sense plant material in such away as to facilitate the micropropagationprocess. As is the case for most of thechapters, the illustrations in this chapterare excellent and enable the reader to gaina sense of the processes, equipment, andapproaches described.

This reviewer considers the price of thisbook ($105.00) a bit on the high side; butthe quality of the book is outstanding andwill likely be a good reference book formodern tissue culturists in the commer-cial world as well as a very useful tool forthose involved in the teaching of classesin propagation, tissue culture, and plantbiotechnology.--PAUL E. READ,Department of Horticulture, Universityof Nebraska, Lincoln, NE 68583-0724. ̄

~ VIDEO

Farmer-to-Farmer: Strategies for Sus-tainable Agrieulture--IPM for Vegeta-bles and Small Fruits--Robert Rooy,producer, in cooperation with the Ro-dale Institute. Rooy Media, 7407Hilltop Drive, Frederick, MD 21702.1992. 29 min. $29.95.

The video presentation on IntegratedPest Management is a general overviewof the topic and acceptable for 4-H, highschool, and grower audiences. Whilesome of the material is similar to materi-al presented in the other videos in this ser-ies (especially use of grower testimony),there is more information presented anddiscussed by academic and professionalentomologists practicing in the field. Thesubject of the video is defined when firstintroduced to the audience and covers allthe aspects of IPM. Unfortunately, thevideo breaks IPM into a basic and ad-vanced concept; when in fact, for IPMto work successfully, all components ofthe 1PM concept have to be both integrat-ed and practiced by growers. The weak-ness of this video is that there was nosummation of the components of IPM atthe end of the video to reinforce IPM con-cepts to the audience.--MICHAEL D.ORZOLEK, Department of Horticulture,The Pennsylvania State University,University Park, PA 16802. ̄

~]~ Book

Conservation of Natural Resources--AResource Management Approach-David A. Castillon. William C. BrownPublishers, 2460 Kerper Blvd., Du-buque, IA 52001. 432 p. $39.00.Paperback.

The book is organized into three mainparts: Physical and Biological Variablesof the Natural Environment, NaturalResource Management, and People-LandEthics-Global Sustainability.

The tone of the book is not protec-tionist. In fact, the book opens with apoignant photograph of the author’s sonin duck-hunting gear with his Labradorretriever. The work is dedicated to thisson, who died at 18. Throughout thebook, I sensed the theme of stewardshipand wise use of resources. As an agrono-mist, I felt the author was too harsh inhis views on modern agronomic practicesand overly enthusiastic about low-inputsustainable agriculture. Many developingcountries with large populations aredegrading their soil, water, and forestresources with over-cutting, over-grazing,farming on steep lands, etc., with whatare clearly low-input traditional culturalpractices.

The section on physical and biologicalresources begins with an overview ofnatural resources, our nation’s (USA)changing view on their use, and a briefhistory of legislation creating nationalparks and forests and regulating the en-vironment. A brief introduction to basicecology concepts is included--producers,consumers, energy flow, etc. The in-troduction is followed by three chaptersthat address basic geologic concepts andthe atmosphere’s and hydrosphere’s rolein managing natural resources. A discus-sion of acid rain is included with a heavyfocus on the USA. It is, of course, aglobal problem.

Chapter 5 covered soil and caused methe most concern as I read it. On page 92,the text says, "the rust red soils of thetropics, from which most of the solubleiron and aluminum have been leached."In fact, the typical tropical soils in humidregions are leached and depleted of bases(calcium, magnesium, potassium, andothers), leaving a B horizon enriched withiron and aluminum. Loamy soils in theMidwest are formed from glacial depositsbut such materials are young, not "an-cient." On the surface area of soil, thepresentation is vague--"acres of surfacearea on the particles of sand and clay"omitting silt and not stating the mass orvolume element of soil. Also on page 92,the statement is made that "only the mi-crobes can take the salt out of soil miner-als and make them available to plants."


Certainly mycorrhizae and rhizospherebacteria assist such processes greatly, butmineral weathering of rocks is a basicchemical change. Healthy soil is certain-ly vibrant with life in the upper horizonsas the author affirms.

Chapter 6 on the biosphere hasthorough sections on nutrient cycles, bio-geography and ecoregions of NorthAmerica. The author discusses the nitro-gen cycle and focuses on nitrogen as acause of eutrophication of lakes. In fact,phosphorus in eroded sediments is moreimportant in eutrophication. The big is-sue with nitrate-nitrogen is contaminationof surface and groundwater drinkingwater supplies. One figure in this chap-ter has an embarrassing gaff in that thearrows are labeled in reverse so that miceeat a fox and owl and a grasshopper eatsa bird in the schematic. However, a verygood combination of graphics and pho-tographs are used to illustrate theecoregions of North America.

Chapter 7 opens the section on natur-al resource management with a presenta-tion on remote sensing, geographicinformation systems, and a brief discus-sion of resource management principles.Subsequent chapters cover forest manage-ment (8), agricultural management (9),rangeland management (10), wildlifemanagement (11), aquatic resources man-agement (12), energy management (l mineral resources (14), and wastemanagement (15), with a primary focuson municipal and industrial wastes. Sever-al glitches occurred in the chapter (9) agricultural management. The nitrogenmanagement text does not mentionanimal manure as a source of N orproblem when huge animal facilities areforced to over-apply manure on adjacentavailable lands. On page 213, the text af-firms that Canada has the reserves ofphosphate rock used for North Americanfertilizers. This is a contradiction of thefigures on pages 330-331 depicting phos-phate ore and evaporite salt reserves inNorth America. Canada has the biggestevaporite salts reserve, which is the potashor potassium fertilizer source. The biggestactive phosphate ore deposits are in Flori-da and North Carolina in the USA. Theauthor should read the case study of"Dick and Sharon Thompson’s ’ProblemChild’: A Decision Case in SustainableAgriculture" (R.K. Crookston and M.J.Stanford, J. Nat. Resourc. Life Sci.Educ., 21:15-19) before affirming sostrongly that no P and K fertilizers areneeded. In my opinion, animal enterprisesand manure as a resource are keys to sus-tainable agriculture systems. U.S. agricul-ture has moved in the direction of intensecash grain farming with no animal enter-prises and huge dairy, swine, beef, and

poultry operations on very limited landareas to effectively use the manureresource resulting in the problem ofanimal "wastes".

Chapter 16 has a brave attempt to layout the human resource issues like popu-lation growth and to establish a world-wide commitment to sustainable resourceuse and to environmental protection.

In summary, this text is very compre-hensive. Each chapter closes with a briefsummary, a key words list, discussionquestions, and references for furtherreading or study. There are many photo-graphs, graphic presentations of con-cepts, plus occasional cartoons with anenvironmental theme or message.

Castillon is to be commended for hisefforts to create a synthesis of geology,ecology, agriculture, and other naturalresources. The bottom line is that I wouldrecommend this text for an overview ofresource conservation and use. There iseasily enough material for a three or foursemester-hour course in this text.-DAVID A. MUNN, The Ohio StateUniversity Agricultural Technical Insti-tute, 1328 Dover Road, Wooster, OH44691. ¯

~ VIDEO

Farmer-to-Farmer: Strategies for Sus-tainable Agriculture--Vegetables--Robert Rooy, producer, in cooperationwith the Rodale Institute. Rooy Media,7407 Hilltop Drive, Frederick, MD21702. 1992. 29 min. $29.95.

The video seems appropriate for 4-H,high school, and part-time grower au-diences, but should be viewed in conjunc-tion with a larger program on cropproduction. The title of the video is mis-leading, since it does not discuss vege-table production specifically, but coversthe elements of crop production in generalincluding manure, crop rotation, covercrops, and integrated pest management.While the concepts presented in this videoare accurate, the method of presentation,grower testimony, does not clearly expressthe concept, and in some cases lacks defi-nition of terms as IPM. The weakness ofthis video is that it does not present anynegatives of the production practices dis-cussed: potential soil compaction, in-creased need for specialty equipment,increased hand labor, and the critical needfor record-keeping. In summary, thisvideo is at best a primer for a nonagricul-tural audience; it does not cover vege-table production, and appears to be bi-ased toward organic crop production.-MICHAEL D. ORZOLEK, Departmentof Horticulture, The Pennsylvania StateUniversity, University Park, PA 16802. ̄

~ BOOK

Microcomputers on the Farm: GettingStarted, 2nd Edition --D.E. Erickson,R.A. Hinton, and R.D. Szoke. IowaState University Press, 2121 S. StateAve., Ames, IA 50010. 1990. 99 p.Softcover. $9.95.

According to it’s Preface, this book isintended to "... present the essentials ofacquiring and using a small computer(microcomputer) in agricultural, opera-tions." The audience of the book is clear-ly farm operators, and no particularknowledge of computers is assumed. Thebrief preface includes some good obser-vations on why farm operators canbenefit from the use of microcomputers.

The book is organized into seven shortchapters. Chapter 1 specifically focuseson the steps that a farm operator shouldtake before buying and using a microcom-puter. Chapter 2 covers farm accountingand record keeping on a microcomputer,which is probably the most common typeof use for farm computers. Chapter 3reports on a limited survey of 12 farmfamilies who had purchased farm com-puters, relating their experiences in buy-ing and using a computer. Chapter 4provides an introduction to types of dataand information that might be appropri-ate for a farm operator to obtain for useon a farm computer. Chapters 5 and 6provide general explanations of computersoftware and hardware, respectively.Chapter 7 is primarily a collection ofchecklists that can be used in buying com-puter hardware and software, and closeswith some summary information andsome observations by an agricultural soft-ware vendor. A useful glossary of sever-al dozen computer terms is included.

The content of the book is appropri-ate to the topic, and well organized.Although readable, the book has a drier,more academic style than is typical offarm periodicals (in some places the tonewas that of a farm management text-book). The challenge in preparing a bookof this type is dealing with the fact thatcomputer technology changes so rapidly.The authors seem to stick to more gener-al concepts that go out of date less quick-ly; for example, software is discussedprimarily in terms of types of softwareavailable, with specific applications list-ed only for examples. However, even useof this more general approach has creat-ed a book that is rapidly becoming out-dated. This problem is illustrated in theauthors’ discussion of storage media,which is limited to floppy disks and fixedhard disks. A present day computer buy-er will find that the number of reason-ably priced storage options has increased,and includes magneto-optical disks (flop-


ticals), and improvements in removablehard drives. Syquest disks, and Bernoul-li removables, and even improvements ina variety of tape formats for archival datastorage. Specific references in the bookto computer capabilities, such as diskstorage capacity, microprocessor type andspeed, and RAM capacity and upgradesare understandable, but are already out-dated (e.g., the book refers to 64 kb RAMupgrades, instead of the 1 and 4 mb RAMupgrades now common).

The part of the book that seems mostoutdated is the chapter on survey infor-mation on farm computer users. Thesmall sample (12 families) was apparent-ly drawn from individuals who had at-tended Cooperative Extension ServiceMeetings put on by University of Illinois.Only three of the 12 computer systemsdescribed had been purchased since 1985(the original edition was published in thatyear), and the survey discussion includescomputers that have been off the marketfor up to 10 years.

The best information in the bookcenters more around the guidelines toconsider in buying a computer. Theauthors appropriately indicate that a farmoperator should first identify needed soft-ware, and only then consider which com-puter to buy, depending on what can runthe software. They clearly describe the im-portance of evaluating not only the capa-bilities of the software, but also thedocumentation that comes with the soft-ware. Support by the computer vendor isstressed as being important, but a signifi-cant omission is reference to the emer-gence of reliable mail order firms, manywith technical support staff, that offersignificant price reductions for both hard-ware and software.

Two of the more insightful parts of thebook were discussion of the social con-sequences of using a computer, and datasources that a computer user can access.The section on social consequencesdescribed the disruption in family life andwork habits that can come about after thefirst purchase of a computer system, par-ticularly as one or more family membersgo through an often intense learningprocess. The section on data sources isvaluable, because the microcomputer canindeed provide an effective way for afarm operator to make better use of com-modity and weather data, research andextension updates, and other types of in-formation.

Overall, this low-priced book is ade-quate as one source of information a farmoperator could use in making computerpurchase decisions. However, much ofthe same information, often in moredepth, and certainly more up-to-date, isavailable in a wide variety of computer

periodicals. While computer periodicalsdo not refer specifically to farm use, theyare normally written in a general style ap-plicable to a wide range of end users.Perhaps a more effective way to commu-nicate the type of information providedin Microcomputers on the Farm would beproviding the same type of computer in-formation in one or more popular farmmagazines. This approach would not onlyreach a much broader audience than thebook, but would allow more up-to-datecomputer information to be used, andwould probably be edited in a way thatwould present the information in the .mostinteresting fashion to a farm audience.bROBERT L. MYERS, Department ofAgronomy, University of Missouri,Columbia, MO 65211. ¯

i~ Book

Manual on Meat Cold Store Operationand Management--G. Cano-Munoz.Unipub, 4611-F Assembly Drive, Lan-ham, MD 20706-4391. 1991. 121 p.$12.00 Paperback.

Meat is a perishable product that re-quires refrigerated and/or frozen storageto preserve shelf-life either in its freshstate or after value-added processing. TheManual on Meat Cold Store Operationand Management is a FAO animalproduction and health publication. It iswritten to be a reference manual for thosewho are either building new or adding onto existing animal food product establish-ments. It is somewhat generic, and pro-vides a general understanding ofrefrigeration, equipment, and its subse-quent operation in meat-food processingand storing establishments.

The manual contains five chapters, thefirst of which is titled "Cold Preservationof Meat Products." The chapter brieflydescribes the general aspects of the needof refrigeration in meat handling begin-ning with chilling after slaughter, subse-quent cold storage of the product,potential problems with storing otherfood products with meat products, a briefdescription on refrigeration used in meatprocessing facilities, general conditionsand need for freezing, comments on prac-tical storage stability, and finally thaw-ing of frozen meat. Often sections in thischapter are sketchy and lacking in ap-propriate detail. However, essentialpoints are covered in almost an outlinedform.

The next chapter is titled "Planning ofCold Storage" and involves general ar-

rangements, management, air circulation,loading and unloading of cold rooms,hygiene and disinfection, handlingmethods and equipment, design, loadingdocks, transport, and layout of a slaugh-terhouse and cutting room. This chaptercovers general items of planning.However, specifics relative to meat oper-ations could be explained in more detail.Design of meat slaughter and processareas is also discussed, but is lacking incompleteness and reflects only the authorsopinion regarding the operation ofspecialized meat facilities. There isdetailed information available to coverthis subject matter, particularly withregard to product flow, sanitation, andoperations performed in specific plantareas.

The third chapter, "RefrigerationEquipment," discusses influences on tem-perature, relative humidity, air circula-tion, evaporator defrosting, condenser,evaporators, and compressors. This chap-ter outlines specific needs for cold storagefacilities and the functions of specificequipment therein. The discussion onrelative humidity appears to relate morefor fruit and vegetables. It is implied thatweight loss of these food products andfactors affecting weight loss may be simi-lar to those of meat-food products. It islikely that a similar series of referencematerials for meat and meat productsdoes not exist. Overall this chapter is well-written and gives many points that needto be considered relative to refrigerationequipment.

The fourth chapter titled "Refrigera-tion Circuit Controls" describes highpressure and low pressure safety pres-sostats, oil pressure control delivery, ther-mostats, water-regulating value,expansion and solenoid valves/thermo-stats, testing safety devices, automation,and the refrigerant circuit. The author de-tails these areas briefly, accurately, andalso provides positive and negative ap-proaches to each type of control that maybe available.

The final chapter is "Costs and Invest-ments" and addresses subjects such asstorage and handling, administration,commercial aspects, insurance, safetyprecautions, and health of personnel.This is done in a very general way and ad-dresses a commercial cold storage facili-ty, not a facility incorporated in a meatprocess plant. Both situations weredetailed up until this chapter. Again, sec-tions are brief and in almost an outlineform. However, most important pointsare generally covered.

Overall, this manual provides a goodgeneral reference for inexperienced in-dividuals who are considering either ren-ovating or building a cold storage facility.

J. Nat. Resour. Life Sci. Educ., VoL 22, no. 1, 1993

It is recommended that readers look toother sources for specifics applied to eachof the generalizations discussed. Titlesand publication dates are mentioned in atleast two or three sections where specificrecommendations are made. However,publisher, page numbers, and/or journalarticles are not included in any of the ci-tations; and there is no reference sectionprovided in the manual.--A.M. BOOR-EN, Department of Food Science & Hu-man Nutrition, Michigan State Univer-sity, East Lansing, MI 48824-1224. ̄

~ VIDEO

Field Crops--Robert Rooy, Producer anddirector. Rooy Media, 7407 HilltopDrive, Frederick, MD 21702. 1992.29min. $29.95.

Rotational Grazing--Robert Rooy,Producer and Director, Rooy Media,7407 Hilltop Drive, Frederick, MD21702. 1992.29 min. $29.95 (Set of for $149.95).

The videos are not intended to providetechnical suggestions and recommenda-tions. They are a forum where farmerswith experience can share their insights,ideas, and observations. Farmers spon-taneously tell of methods they have usedto develop lower, and sometimeseliminate, the use of pesticides, herbi-cides, and synthetic fertilizers. Statementsmade by the farmers may not be support-ed by scientific data. Some implicationsthat doomsday will soon appear maycause a reverse reaction. The major themestresses organic farming and sustainableagriculture.

Some concepts as presented may bemisleading when not explained in a fullcontext. Statement: "Cultivation may beless expensive than chemicals." Fact: Thecost of fuel for cultivation may be off-setting. Statement: "Organic nitrogentends to be a less polluting nitrogensource." Fact: Mineralization must occurbefore use of N by plants and thus pollu-tion potential may be the same.

Some ideas as suggested are soundmanagement practices and are not exclu-sive to sustainable agriculture. The videowould serve high school students andthose with non-farm background whoneed an appreciation of the efforts re-quired to produce food and fiber in anenvironmentally conscious way.--DALED. WOLF and GREG K. EVANYLO,Crop and Soil Environmental SciencesDepartment, Virginia Tech, Blacksburg,VA 24061. ¯

~ BOOK

Economic Models of Agricultural LandConservation and EnvironmentalImprovement--Edited by Earl O.Heady and Gary F. Vocke. Iowa StateUniversity Press, 2121 S. State Avenue,Ames, Iowa 50010. 1992.275 p. Hard-cover. $44.95.

The Center for Agricultural and RuralDevelopment (CARD), founded in 1958by the late Professor Earl O. Heady, wasone of the earliest major forces in agricul-tural policy analysis. Heady and Vockehave assembled a series of 11 studies thatdocument CARD’s involvement in en-vironmental issues. These papers providea historical review of the work performedby Heady and his associates at CARD.As such, this book is a tribute to CARD’srole, in general, and Heady’s role, in par-ticular, in influencing agricultural policy.As noted by Stanley R. Johnson in theForeword, this role is understated by theeditors and authors.

"What might be the potentials, possi-bilities, restraints, and conditions if we tryprograms in the future which have notbeen tried in the past" (p. xii) is the gener-al question addressed. A series of inter-regional competition models aredeveloped to answer this question. Twooverriding factors in these models are theuse of linear programming (LP) as thebasis to solve the models and their struc-tural similarity. Of the 11 studies, eightuse LP. Quadratic programming, sepa-rable programming, and combining LPand econometric modeling are employedin the remaining three studies. Eachstudy’s model has the same basic struc-ture (beyond being LP) and many aremodifications of earlier CARD models.

One shortcoming of the book is thefailure to use the same notation in eachstudy. Because of the similarities in struc-ture, using the same notations would haveincreased the overall appeal of the book.This is not to imply the same model wasused in each study, but rather the modelshave a common base. A strength of thebook is the excellent model developmentdiscussion provided by each study.

Five sections comprise the makeup ofthe book. Each section is concerned witha general environmental issue. Two orthree studies are included in each section,except the fourth, which contains only asingle study. The first section focuses onthe consequences of reducing soil erosionfrom cultivated lands. Determining theadequacy of land and water resources tomeet future agr’~cultural demand givengovernmental policies to achieve an en-vironmental goal is the focus of thesecond section. Potential policy optionsaffecting the impact of agriculture on

water quality are the subject of the thirdsection. Long-run productivity of agricul-tural land is addressed in the fourth sec-tion. Finally, incorporating demandrelationships is the focus of the fifth sec-tion. Topics addressed in the fifth sectionare diverse, covering limiting the rates ofnitrogen fertilizer, banning insecticides,and soil conservation.

Interregional competition and adjust-ment to policy changes are the overrid-ing themes in each study. This theme isaddressed by dividing the USA into sever-al regions and modeling each region.Several of the studies take this to a fur-ther extreme and model Iowa as severalseparate regions. The strength and use-fulness of this book lies in its presenta-tion of the models. This book is a goodreference book on modeling interregion-al competition in a LP framework. Thisis in spite of the previous noted weaknessof varying notation between studies.

Heady and Vocke’s book will have lim-ited audience because of the nature of thestudies and the dated results. As a refer-ence book, it will appeal to readers inter-ested in: (i) modeling interregionalcompetition in an LP framework,, and (ii)a historical perspective of agriculturalpolicy research. Results presented aredated, with the most recent study beingpublished in 1982. The major weaknessof the book is the limited presentation onmodel validation and/or verification.Keep in mind that the book serves as atribute to Heady and his associates atCARD. In this respect, Heady and Vockeachieve their objective.--JAMES W.MJELDE, Department of AgriculturalEconomics, Texas A&M University, Col-lege Station, TX 77843. ̄


STUDENT ESSAYSThe following articles are the winning essays from the 1992 American Society of Agronomy Student Essay Con-

test. The essays are published here with the understanding that the students’ advisors or other departmental facultywould be asked to make editorial corrections. In fact all our professional journals have the proofreading and editorialassistance of secretaries, colleagues, peer reviewers, and staff editors at ASA headquarters.

First Place

Developing Crop Resistance to the Russian Wheat AphidBrian Vaughn

ABSTRACT

SINCE 1986, western and central agricultural regionshave been swept by a new insect species not native

to the continental United States. Spread of the Russianwheat aphid (Diuraphis noxia) started a fear that grewat a frenzied rate. Within a year after the first aphid wasdetected near Muleshoe, Texas, the aphid had beenreported in seven states in the Southern and Central GreatPlains. Within another year, the aphid had been foundin a total of fourteen states. By 1988, the Russian wheataphid was discovered in areas as far north as Saskatche-wan and two other provinces of Canada (Massey andCoppeck, 1989). The current distribution includes 17western states (Burton, 1992) (Fig.

Ever since the first reports of Russian wheat aphids inthe United States were released, scientists have been try-ing to determine ways to stop advancement of the pest.Among the leaders in this effort are scientists at theUSDA-ARS Plant Science Research Laboratory in Still-water, OK, headquarters for Russian wheat aphidresearch in the United States. The first steps were to de-termine the history, physiology, life cycle, feeding habits,and potential sources of resistance. Over 35,000 smallgrain lines have already been evaluated for possibleresistance to the Russian wheat aphid. Today, major ef-forts are underway to develop resistant plant varieties(Burton, 1992).

Understanding the history of the Russian wheat aphidis an important key to finding its possible weaknesses.Developing resistant crops could depend on finding resis-tant strains of crops near its places of origin. The aphidis indigenous to southern Russia and its existence wasknown as early as 1900. Within the period of 1900 to1978, the pest was considered of minor importance. In1978, however, the aphid caused severe damage to thewheat crop in South Africa’s Orange Free State. Withinthree years all of South Africa and even parts of Mexicohad identified the aphid (Massey and Coppock, 1989).Even though the name Russian wheat aphid describes the

Department of Agronomy, Oklahoma State Univ., Stillwater, OK 74078.

Published in J. Nat. Resour. Life Sci. Educ. 22:61-62 (1993).

host plant as wheat, barley and other small grains are alsotargets of the aphid. In addition, the Russian wheat aphidfeeds on other grasses, especially cool season species suchas jointed goatgrass, bromegrasses, wheatgrasses, andwildrye (Morrison, 1989).

The Russian wheat aphid is not similar to any otherspecies of aphid. Although it is about the same size asthe greenbug, the Russian wheat aphid is distinguishedby a characteristic projection above the cauda (tail) andthe absence of prominent cornicles (dorsal tubes) typicalof other aphids (Fig. 2). The Russian wheat aphid is lightgreen in color without a stripe in the middle of the bodytypical of many other aphids. It has an elongated, spindle-shaped body less than two millimeters in length (Masseyand Coppock, 1989; Morrison, 1989).

Understanding the life cycle of the Russian wheat aphidis another important aspect of research and development.A better knowledge of aphid life cycles could help pro-vide ways of controlling the growth of the population.Russian wheat aphids, like many other aphids, do nothave males in the population. Rather, each aphidproduces asexually by parthenogenesis. This type ofreproduction allows the young to be born in the nymphstage without an egg stage. At maturity, which can oc-cur within a week after birth, an aphid can produce asmany as four offspring in one day under favorable con-ditions. If high populations occur, specialized aphidsproduce wings and use the winds to produce a new colonyof aphids. The complete life span of a Russian wheataphid is estimated at 40 days.

Evaluating feeding habits of the aphid is one impor-tant approach to understanding how plants may resistaphid feeding. After the aphid attaches itself to thedesired host, either by flight or by crawling, it probes andin a way "feels" the plant. The investigation is notdifficult for the aphid who possesses mechanoreceptorson its antennae, legs, and mouthparts. Probing beginswith the stylet, where small droplets of saliva areproduced and placed on the desired point of entry. Thesaliva contains enzymes that help dissolve the fibrousmaterial of the plant. After an opening is produced, theproboscis of the insect is injected into the opening while


RUSSIAN WHEAT APHID, 1986-1991

Fig. 2. Scanning electron microscope photo of the Russian wheat aphid showing the “double tail” appearance and absence of distinct cornicles (from USDA-ARS, Stillwater, OK).

the saliva continues to be produced and dissolve the en- trance. Soon the proboscis enters the phloem vessel. Be- cause of the pressure within the phloem the aphid is literally force-fed (Tarn and Adams, 1982).

The task of finding more information about feeding habits is an important part of the Stillwater USDA Plant Science Research Laboratory effort. Dr. James Webster, research entomologist, uses electrical feeding monitors to determine resistance or tolerance of plants and the reac- tions of the aphids. Webster has screened many varieties of wheat, barley, and other small grains with hopes of finding some sign of resistance. To more completely evaluate the amount and type of resistance, an aphid is placed on the plant. A harness is attached to the aphid using a small droplet of liquid silver glue. The droplet is placed at the end of the spider-web thin gold thread. At the opposite end, the thread is soldered to a copper wire. A probe, also made of copper, is placed in the soil which contains the plant. The wire and glue contain a very low electrical voltage which passes through the insect. When the insect reaches the phloem, the circuit is completed (Causley, 1985). Meanwhile, a graph printer records data from the different levels of voltages received by the measurement system.

Webster and his associates examine the data and com- pare the aphid feeding patterns on different strains of plants to determine the levels of resistance or tolerance. Tolerance is indicated when the aphid enters the phloem and feeds readily, but the plant survives heavy aphid in- festations. Resistance can be quantified by observing the time needed for the insect to reach the phloem and the time spent feeding. Russian wheat aphids feeding on resistant barley lines spend less time in phloem feeding activity than on susceptible lines, and also do not grow as rapidly (Burton, 1992).

In conclusion, all of the information collected is used to reach the main goal of developing a resistant strain of each crop affected by the Russian wheat aphid. Once resistance is found, the development of agronomically adapted resistant strains may take from seven to ten years.

Surveyed, found

No hostcrop

0 No data

Fig. 1. Distribution of the Russian wheat aphid in the United States (from Burton, 1992).

The use of germplasm from around the world will help save time and money for the agriculture community. To date, damage by Russian wheat aphid to small grains in the United States has exceeded $650 million (Burton, 1992). Great progress is being made in the research with Russian wheat aphid, and within a few years, geneticists hope to have developed resistant strains of all crops harmed by the Russian wheat aphid.

REFERENCES

Burton, R. 1992. The Russian Wheat Aphid Fourth Annual Report. Agric. Res. Service Progress Rep. PSWCL Prog. Rep. 92-001. USDA- ARS, Stillwater, OK.

Causley, F. 1985. Ryan “Leashes” Greenbugs. Stillwater Newspress. Sunday, Sept. 29, p. 2E.

Massey B. and S. Coppock. 1989. The Russian wheat aphid in Okla- homa. OSU Ext. Fact Sheet 7183. Coop. Ext. Service, Oklahoma State Univ., Stillwater, OK.

Morrison, P. 1989. Russian wheat aphid. p. 18-19. In Wheat pest management. Coop. Ext. Service/Wheat Industry Resource Com- mittee. Loren Technical Production, Bozeman, MT.

Tarn, T.R., and J.B. Adams. 1982. Aphid probing and feeding, elec- tronic monitoring, and plant breeding. p. 221-246. In Pathogens, vectors, and plant diseases. Academic Press, New York..

62 J. Net. Resour. Life Sci. Educ., Yo/. 22, no. 1, 1993

Second Place

The Relationship of Varied Seeding Rates, Leaf Area,and Yield in Barley in the Midwestern United States

Todd Frank

ABSTRACT

The objective of this experiment was to determine the rela-tionship of leaf area to plant densities lower, higher, and equalto the standard seeding rates for barley in the Midwestern UnitedStates. The objective will be determined using the six-rowedMidwestern malting barley Excel. Data was collected in a 1991summer field experiment at St. Paul, MN. Seeding rates of 48,72, 95, 191, and 477 kg ha-I were considered in the experi-ment. The data collected included cu|m number and the leafarea from a .14 m2 plot. Percent emergence decreased as theseeding rate increased. Two to three tillers were observed in theseeding rates of 48, 72, and 95 kg ha -1 and one or less in theseeding rates of 191 and 477 kg ha-!. The results showed sig-nificant differences in yields between the seeding rate of 95 kgha -t and the rates of 48 and 72 kg ha -~. Seeding rates of 191and 477 kg ha-t showed no significant differences in yieldcompared to the rate of 95 kg ha - i. The seeding rate of 95 kgha-I provided a leaf area that was significantly greater thanthe lower seeding rates, but not the higher seeding rates. Theaverage leaf area per culm proved statistically significant at seed-ing rates higher than 95 kg ha- ~, but no significance betweenthe lower rates.

SMALL GRAINS such as wheat and barley have been im-portant to humans as a food source since the be-

ginning of agriculture. Small grains provide about fiftypercent of the world’s total food supply. Many factorsaffect the yield potential of small grains. The factor be-ing considered is plant density in relation to leaf area andgrain yield. According to the Varietal Trials of SelectedFarm Crops (7), one must remember that the standardseeding rate used will vary depending on desired stand,expected mortality, emerging ability, seed weight, seedgermination, seedbed condition, depth of planting, andplanting equipment. Therefore, seeding rates must be ad-justed accordingly to compensate for the factors listedabove.

Experiments were conducted at the Waite Agricultur-al Research Institute in Queensland, Australia to view theeffects of planting density and grain yield of contrastingcultivars of barley over a three year period. The main ob-jective was to determine how well the cultivars withstoodhigh moisture in early season followed by drought atmaturity. Growth and yield of two uniculm barley lines,

Department of Agronomy and Plant Genetics, Univ. of Minnesota, St.Paul, MN 55108.

Published in J. Nat. Resour. Life Sci. Educ. 22:63-65 0993).

WID-103 and WID-105, and the commercial varieties,Galleon an~ Schooner, were compared over a range ofplanting rates varying from 50 to 400 kg ha-~. These ex-periments were conducted in 1986, 1987, and 1988 byMcDonald (5). McDonald (5) observed that plant popu-lations measured early in the season ranged from 39 to109 m-2, which later resulted in grain yields rangingfrom 97 to 711 grams m-2. The tillered varieties had sixpercent more yield in comparisons of yield betweenuniculm versus tillering varieties. One of McDonald’s (5)conclusions was that to improve yield of uniculm lines,greater leaf area per culm is necessary.

Fukai et al. (1) working with barley cultivars with limit-ed tillering capabilities, reported that grain yield tendedto increase with increases in plant density up to 150 plantsm-2. Results of their experiment showed that cultivarswhich developed a crop canopy most quickly shaded theground and were the highest yielding. The cultivar whichhad the highest light interception per unit leaf area alsohad the highest dry-matter production.

Greater light interception, therefore a larger leaf area,is essential to grain fill for optimum yields. Photosyn-thetically active radiation (PAR) is a major factor in yielddetermination of small grains. Kostrej (4) reported theabsorption of radiation depends not only on leaf area butalso on its distribution within the stand profile. Decreasedlight interception leads to decreased overall photosyn-thesis and therefore, yields decreased.

Richards (6) claimed that a tiller inhibitor gene in wheatresulted in lower tiller number with increased specific leafweight, stem density, and kernels per culm; however thegene did not significantly affect grain yield. Similar grainyield results were found in the genotypes used in a studyby Huel and Becker (3) that were quite diverse; Neepawa(high tillering), Siete Cerros (low tillering), and M1417(oligoculm).

The objective of this experiment is to determine therelationship of leaf area to plant densities at rates lower,higher, and equal to the standard seeding rates for barleyin the Midwestern United States. Conclusions will bereached to determine the optimum seeding rate for barleyusing a leaf area index and grain yield as the determin-ing factors.

MATERIALS AND METHODS

This study was conducted during the 1991 summergrowing season in field plots at St. Paul, MN. A Mid-western malting six-rowed barley cultivar, Excel, was used


throughout the study to demonstrate the relationship ofyield and leaf area to plant density. The experiment wasplanted April 19, with seeding rates of 48, 72, 95, 191,and 477 kg ha-l; 95 kg ha-] is considered the recom-mended seeding rate for barley in the Midwestern UnitedStates.

The experimental design was a randomized completeblock design with three replications. Plots consisted ofthree 3.7 meter rows spread 15 cm apart. The plots werespaced 46 cm apart.

All data was taken from a 0.9 m random section ofthe center row of each plot. The total number of culmswere counted at plant emergence and at three, one weekintervals after emergence (April 30, May 7, May 14, andMay 21). These counts were used to calculate plant den-sity and culms per area.

On May 24, at the Zadok’s 2.3 growth stage (8), theleaf area per plant and total leaf area for the 0.9 m rowsection was determined on freshly harvested plants. Leafarea of each plot was measured using a LI-3000 leaf areamachine (LI-COR Inc., Lincoln, NE).

The data were analyzed using regression analysis withnumber of culms as the dependent variable in all regres-sion analyses and total leaf area or leaf area plant -1 asindependent variables.

RESULTS AND DISCUSSION

Culm number per area increased dramatically over timein the 477 kg ha- ] seeding rate, compared to the otherseeding rates of 48, 72, 95, and 191 kg ha-~. The per-cent emergence for the experiment was 70, 56, 60, 55,and 30 for the seeding rates of 48, 72, 95, 191, and 477kg ha-l, respectively. The "crowding effects" in thehigh densities (191 and 477 kg ha-l) resulted in oneshoot per plant, as well as plant mortality (Fig. 1). Twoto three shoots were observed in the lower seeding ratesof 48, 72, and 95 kg ha-l. Tillering occurred earlier inthe growing season at the lower seeding rates to compen-sate for the lower density. As the seeding rate increased,the plants had more of a tendency to be uniculm andrefrain from tillering.

The plant density interactions with the leaf area canbe viewed in Fig. 2. At the lower seeding rates (48 and

160

140

120

100

20

Dc~ys After Planting

I’-~-477 kgha-1 --+--191 kghe-I -~-’-95 kg ha-1

~ 72 kg ha-1 --x---- 48 kg ha-1

Fig. 1. The average number of culms per 0.91 m at several days afterplanting for the five planting rates.

1000 olal Ave Leaf Area48 72 95 191 477

Seeding Rate in kg ha-1Fig. 2. The total average leaf area in sq cm per 0.91 m for the five seed-

ing rates.

72 kg ha-]) there was no significant difference in leafarea. As the planting rate increased, so did the total aver-age leaf area. The average leaf area per culm was signifi-cantly greater for the planting rates of 48, 72, and 95 kgha-] (Fig. 3). There was no difference between the threelower rates, but there was a statistically significant differ-ence between the 95 and the 191 kg ha-] seeding rates.The data further indicate that 95 kg ha- ] was the opti-mum seeding rate for the experiment.

The leaf area started to decrease significantly at higherrates, which was not justified by increasing seed costs toplant at the higher densities (Fig. 3). Although seedingrates lower than 95 kg ha - ] had a similar leaf area, theydid not yield as well as the 95 kg ha- 1 seeding rate. Eventhough the lower rates had the capacity to tiller they werenot able to carry on the amount of photosynthesis (e.g.,intercept as much radiation) as the 95 kg ha-] seedingrate.

According to a study by Green (2), yield varies acrossdifferent seeding rates and morphotypes. There was a sig-nificant quadratic and linear response between the meanmorphotype seeding rates of 65 and 95 kg ha- 1, but nosignificant difference between the 95, 125, and 155 kgha- ~ seeding rates. Therefore, seeding rates above 95 kgha - ] would not be economically justified because of theincrease in seed costs at the higher seeding rates.

20 Area per Culm48 72 95 191 477

Seeding Rote in kg ha-1

Fig. 3. The average leaf area per culm at the five seeding rates.


CONCLUSION

In conclusion, the conventional seeding rate of 95 kgha ~' was the optimum planting density for barley in thisstudy. The data are based on the fact that the highest leafarea per culm was obtained at the 95 kg ha ~' plantingrate. Fukai et al. (1) showed that those cultivars thatproduced the quickest ground canopy were the highestyielding. Although the lower plant densities had as highof a leaf area per culm, the yields were significantly low-er for planting densities less than 95 kg ha ~'. Plantingat rates higher than 95 kg ha"1 does not appear justi-fied because of the higher cost of seed to produce thesame yields. The rate of 95 kg ha"1 allowed tillering tooccur if environmental conditions favor tillering. Tiller-ing allowed for a higher harvest index, which increasedthe yield more than any other factor. To acquire a highharvest index it is necessary to plant the optimum seed-ing rate.

Finally, it is apparent that the yield of small grains willnot increase significantly at rates higher than 95 kgha"1. At rates higher than 95 kg ha"1, "crowding ef-fects" occur and tillering is restricted to one shoot or less.

Two to three shoots per plant were observed in seedingrates lower than 191 kg ha"1. This study has also shownthat tillering and photosynthesis from increased leaf areaper culm at seeding rates lower than 95 kg ha "' are notsufficient to suggest significant differences in yield.

List of Reviewers for theJournal of Natural Resources and Life Sciences Education

1 January-31 December 1992

Maintaining the editorial standards of a scientific jour-nal is an important responsibility, because the publica-tions of a society are one of its major services to itsmembers. Maintaining such standards is the ultimateresponsibility of the journal editors, and this task can onlybe accomplished with the advice of associate and con-sulting editors and a large number of colleagues who areinvited to review manuscripts. Their critical commentsand helpful suggestions have played a major part in mak-ing the Journal of Natural Resources and Life SciencesEducation a success. The members of the JNRLSEEditorial Board want to express their appreciation to thefollowing individuals who helped review manuscripts forthe 1992 issues. This list may not be complete due toproblems in collating such information from manysources. We extend our apologies to those reviewerswhose names have not been included.

Anderson, M.R., Wilmington College, OhioAnderson, W.A., Ohio State University, Agric. Technical Institute,

WoosterApplegate, J., Cook College, New Brunswick, New Jersey

Barber, J., Oklahoma State UniversityBennett, W.F., Texas Tech UniversityBlevins, D.G., University of MissouriBlue, W.G., University of Florida

Boerboom, C.M., Washington State UniversityBoggess, W.G., University of FloridaBowman, D.C., University of NevadaBoyd, A.M., Mississippi State UniversityBuhr, K.L., University of FloridaBurnham, B.R., Utah State UniversityBurrill, L., Oregon State UniversityBusacca, A.J., Washington State University

Carroll, M.J., University of MarylandClapham, W.M., University of MaineCoffman, C.G., Texas A&M UniversityConklin, A.R., Wilmington College, OhioCox, W.J., Cornell University

Daie, J., Cook College, New Brunswick, New JerseyDanneberger, T.K., The Ohio State UniversityDavis, M., University of ArkansasDenton, P., University of TennesseeDunn, S.J., North Carolina A&T University, GreensboroDunphy, E.J., North Carolina State University

Elkins, D.M., Southern Illinois UniversityEngle, C.F., Washington State UniversityEssington, M.E., University of TennesseeEvans, G., Oregon State University

Fenwick, J.R., Colorado State UniversityPick, G.W., Cornell UniversityFike, W.T., North Carolina State UniversityFjell, D.L., Kansas State University

J. Nat. Resour. Life Sci. Educ., Vol. 22, no. 1, 1993 • 65

Ford, D.M., Northeastern Missouri State UniversityFribourg, H.A., University of TennesseeFrye, W.W., University of Kentucky

Glover, C.K., New Mexico State UniversityGorchov, D., Miami University, Oxford, OHGrabau, L.J., University of KentuckyGreub, L.J., University of Wisconsin, River FallsGroffman, P., University of Rhode IslandGroose, R.W., University of WyomingGuthrie, M.L., University of MinnesotaGuy, S.O., University of Idaho

Hartel, P.G., University of GeorgiaHartzler, R.G., iowa State UniversityHawes, D.T., Piano, TexasHenning, J.C., University of KentuckyHicks, D.R., University of Minnesota

Jensen, G.L., Montana State UniversityJohnson III, W.C., USDA-Coastal Plain Station, Tifton, GeorgiaJohnson, B.N., Oklahoma State UniversityJohnson, C., USDA-ARS, Tifton, GeorgiaJohnson, J.W., The Ohio State UniversityJohnson, K.D., Purdue UniversityJohnson, R.E., Western Kentucky University, Bowling GreenJordan, D., University of Missouri

Kaiser, J., University of IllinoisKells, J.J., Michigan State UniversityKhan, A., Western Missouri State CollegeKidder, G., University of FloridaKillorn, R.J., Iowa State UniversityKnapp, S.J., Oregon State UniversityKnutson, K., Colorado State UniversityKremer, E., Oklahoma State University

Lang, C., Cook College, New Brunswick, New JerseyLessman, G.M., University of TennesseeLoynachan, T.E., Iowa State University

Makaroff, C.A., Miami University, Oxford, OhioMason, S.C., University of NebraskaMays, M.D., Soil Conservation Service, Lincoln, NebraskaMcCloskey, W., University of ArizonaMcConkey, B.G., Washington State UniversityMeade, J.A., Cook College, New Brunswick, New JerseyMedley, K., Miami University, Oxford, OhioMiles, R.J., University of Missouri

Mueller, J.P., North Carolina State UniversityMurdock, L.W., University of Kentucky, Princeton

Oplinger, E.S., University of Wisconsin, Madison

Park, W., University of TennesseePerry, W., Morgantown, WVPinkerton, B.W., Clemson University

Quick, J.S., Colorado State University

Rayburn, A.L., University of IllinoisReese, P.F., Tidewater Research Center, Suffolk, VirginiaReganold, J.P., Washington State UniversityReid, J.L., USDAoARS, Washington State UniversityRomanko, R.R., University of IdahoRouget, H., Saymaw, MichiganRudolf, W.R., Lathrop, Missouri

Salvador, R.J., Iowa State UniversitySammons, D.J., University of MarylandSchwartz, H., Colorado State UniversityScott, H.D., University of ArkansasShanahan, J.F., Colorado State UniversitySimmons, S.R., University of MinnesotaSmith-Huerta, N.L., Miami University, Oxford, OhioSmith, D.H., Colorado State UniversitySmith, T.L., California Polytechnic University, San Luis ObispoStiegler, J.H., Oklahoma State UniversitySwisher, M.E., University of Florida

Thien, S.J., Kansas State UniversityThomason, R.C., Western Texas State UniversityThomison, P.R., The Ohio State UniversityThornton, M., University of IdahoTimm, K., Colorado State UniversityTurco, R.F., Purdue UniversityTwidwell, E.K., South Dakota State University

Vorst, J.J., Purdue University

Wicks, G.A., University of NebraskaWilson, K.G., Miami University, Oxford, OhioWilson, R.G., Scottsbluff, NebraskaWofford, D.S., University of FloridaWolf, D.C., University of Arkansas

Zelinski, M., University Extension, Fredericktown, Missouri

BE AVOLUNTEER

Conmc~ Your County Extension Office

66 ¯ J. Nat. Resour. Life Sci. Educ., Vol. 22, no. 1, 1993

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