“IN SITU” WATER HARVESTING FOR CROP PRODUCTION...

XI IRCSA CONFERENCE – PROCEEDINGS

“IN SITU” WATER HARVESTING FOR CROP PRODUCTION IN SEMIARID REGIONS

CAPTACIÓN “IN SITU” DEL AGUA DE LLUVIA

PARA LA PRODUCCIÓN DE CULTIVOS EN REGIONES SEMIÁRIDAS

Eusebio Ventura, Jr. School of Engineering - University of Queretaro. C.U. Cerro de las Campanas s/n. Queretaro, México.

76010. [email protected].

L. Darrell Norton. USDA-ARS-NSERL-Purdue University, 1196 Soils Bldg., West Lafayette, IN, 47906. [email protected]

Keith Ward. Sustainable Agricultural Technologies, LLC. P.O. Box 591, Corydon, IN. 47112. Manuel López-Bautista and Alfredo Tapia-Naranjo. INIFAP-Queretaro. Av. Pasteur Sur # 414, Queretaro, 76040, México.

ABSTRACT

Many arid or semiarid countries experience significant problems with water for rainfed crop production. Semiarid regions may receive sufficient rainwater to support crops, but it is distributed so unevenly in time and/or space that rainfed agriculture is not always successful. Developing technologies to increase agricultural water use efficiency through water harvesting and conservation is a need. The objective of this study was to develop and evaluate a new integrated Reservoir Tillage System (RTS) for crop production in semiarid areas. The system included the design of a horizontal-cut subsoiler, a modified row planter and a roller formed with plastic wheels to improve soil tilth and create minireservoirs on the soil surface for “In situ” rainwater harvesting. The roller was tested in laboratory conditions for soil and water conservation using simulated rainfall. The new RTS was implemented in field during the 2002 rainy season at three locations in semiarid Central Mexico. Five different varieties of common beans were planted. A control plot was planted according to the farmer´s conventional procedures. The roller was able to reduce soil erosion and runoff and increase infiltration significantly as compared to the control in the laboratory experiments. In the field, a more uniform seedling emergence and greater standing population was observed in the three sites where the system was implemented. Soil water content was greater in the new RTS than the conventional system, which resulted in greater crop growth and increments of yields in the average of 100% for the different beans varieties.

Keywords. Reservoir Tillage System, Water harvesting, Soil and Water Conservation.

mailto:[email protected]

mailto:[email protected]


Introduction

Eight hundred million people are food-insecure, and 166 million pre-school children are

malnourished in the developing world. Producing enough food, and generating adequate

income in the developing world to better feed the poor and reduce the number of those

suffering will be a great challenge. This challenge is likely to intensify, with a global

population that is projected to increase to 7.8 billion people in 2025, putting even greater

pressure on world food security, especially in developing countries where more than 80

percent of the population increase is expected to occur. Irrigated agriculture has been an

important contributor to the expansion of national and world food supplies since the 1960s,

and is expected to play a major role in feeding the growing world population (Rosegrant et al.,

2002). However, irrigation accounts for 72% global and 90% of developing countries water

withdrawal, and water availability is becoming a major limiting factor. In fact, in several parts

of the world, water demands are fast approaching the limits of resources. When scarcities

increase, cities and farmers begin to compete for available water.

Rainfed agriculture is also very important and it accounts for 58% of world food production

(Rosegrant et al., 2002). In fact, 69% of cereal production is rainfed. However, many

developing countries located in arid or semiarid regions experience significant problems with

water for rainfed crop production. Water scarcity problems in arid regions result simply from

the lack of sufficient rainfall. Semiarid regions, on the other hand, may receive sufficient

rainwater to support crops but it is distributed so unevenly in time and/or space that rainfed

agriculture is not viable.

An associated problem with rainfed agriculture is soil erosion and degradation. Soil erosion is

a serious environmental threat, which combined with other problems, is risking the long-term

future of agriculture worldwide. In the last 50 years it is estimated that the world has last over

one third of the land available for cultivation. That loss is accelerating rapidly and it is known

that some 10 million hectares of land are lost to agricultural production each year worldwide

(Kaufmann and Franz, 2000).

Therefore, there is a need to design integrated technologies to increase agricultural water

use efficiency through rainwater harvesting while conserving the soil in rainfed areas. Under

these considerations, the purpose of this paper is to present the development and evaluation


of a new integrated Reservoir Tillage System (RTS) as an alternative for crop production in

semiarid regions.

Literature Review

Water harvesting is a general term used to describe the collection and concentration of

runoff for many uses, including agricultural and domestic use. In the original concept, most

water harvesting techniques consist of a catchment area and a receiving area for the capture

of runoff. The areas are generally small in size and harvesting occurs near where the rain

falls. Pacey and Cullis (1986) classify rainwater-harvesting techniques in three broad

categories: macrocatchment water harvesting, microcatchments, and rooftop runoff

collection. Macrocatchment rainwater harvesting includes the collection of water from large

areas substantially far from the cropped areas. Microcatchment rainwater harvesting is a

system where the collection and the cropped area are distinct but adjacent to each other.

Rooftop runoff collection involves the collection of runoff from slanted building roofs and is

used almost exclusively for domestic consumption.

In situ water harvesting, also known as water conservation, may be close to the definition of

microcatchments techniques, but in any case, it becomes an alternative in arid and semi-arid

regions, where precipitation is low or infrequent during the dry season and there is a need to

store the maximum amount of rainwater during the wet season for use at a later time,

especially for agricultural and domestic water supply (OAS, 1997). The in situ technology

consists of making storage available in areas where the water is going to be utilized. Some

water conservation methods such as mulching, deep tillage, contour farming and ridging are

often referred to as in situ rainwater harvesting techniques (Habitu and Mahoo, 1999). The

purpose of these methods is to ensure that rainwater is held long enough on the cropped

area to allow more water infiltration into the soil. Deep tillage is a water conservation

technique that improves soil moisture capacity by increasing soil porosity. In addition, runoff

is reduced through increased roughness at the soil surface, which in turns increases the time

available for water to infiltrate into the soil.

Another concept related to rainwater harvesting that involves different techniques “Reservoir Tillage (RT)”. This approach was developed under the consideration that tillage can provide

increased levels of surface storage, which may turn in one of the most effective means of


controlling both runoff and soil erosion. Reservoir tillage creates basins or pits to hold water

in place, allowing it to infiltrate the soil, thus preventing runoff.

Hansen and Trimmer (1997) report that reservoirs or basins are created with specialized

commercially available tillage machines, which catch and hold water in place until it can

infiltrate into the soil. Two basic methods are commonly used to construct reservoirs. One

method is pitting--punching holes or depressions 6 to 10 inches in diameter, 6 to 8 inches

deep, and spaced about 2 feet on center into the soil. The other method builds up small

earthen dams or dikes with a tillage tool that scrapes and carries loose soil down the furrow.

The tool trips at preset intervals, creating small dams in the furrows to retain rainwater. Small

basins created by these dikes hold the precipitation until it can infiltrate the soil.

The Texas Water Resources Institute (1985) reported that during one 24-hour period at

Bushland, diked furrows held six inches of rain without runoff. Furrow diking is also

economical--the equipment needed to form dikes can pay for itself in just one season with

increased yields from only 75 acres of cotton. In comparing fields with and without furrow

diking, researchers at Vernon have found that diking can increase cotton yields by 25% and

sorghum yields by as much as 30%. Research at Vernon has shown that just one inch of

moisture stored in a field increases cotton lint yield by 30 pounds, while scientists near

Amarillo have learned that one inch of water stored in the soil may increase grain sorghum

yields by 350 pounds per acre and wheat yields by 2.5 bushels per acre. It's estimated that

more than 3 million acres are now furrow diked at some time during the year.

Kranz and Eisenhauer (1990) used a continuous-application rainfall simulator to apply water

at rates similar to the peak rates of center pivot irrigation systems equipped with low pressure

spray sprinkler packages. Three interrow tillage treatments—implanted reservoir, basin till,

and subsoiler were compared to conventional tillage for two field slope conditions (1% and

10%). At 10% field slope, reservoir tillage in the interrow area reduced runoff by 68% and soil

erosion by 92% compared to the conventional treatment. At the same slopes, the

conventional treatment resulted in greater erosion than the implanted reservoir and basin till

treatments. However, at 1% field slopes, no difference in runoff volume was measured.

Tillage that provided increased levels of surface storage provided the most effective means of

controlling both runoff and soil erosion.


Arstad and Miller (1973) found that placing small basins or plant residues between crop rows

reduced runoff from 40 percent to 1 percent and increased sugar beet and potato yields

under center-pivot sprinklers and machines and cultural practices. Since then there has been

a development of machines for the construction of small basins (reservoir tillage) but still, a

general acceptance of reservoir tillage systems in semiarid areas has not taken place due to

the limitations of each of the systems. What is required is an integrated system that would

combine the surface water capability of the plough with the fine tilth required for profitable

plant growth, at an acceptable cost. One of the recent alternatives to this problem is the

Aqueel wheel.

The Aqueel , originally conceived by a UK potato farmer, is the trade name for a unique

means of creating indentations in a loose soil surface that act as reservoirs for the storage of

water. When grouped together the Aqueel wheels make a continuous roller, which can

match the implement to which it is attached. In order for different growing practices to be

accommodated, such as ridge, furrow, bed, flat or different row widths, spaces can be

introduced between each Aqueel allowing any desired topological arrangement. Its operation

is primarily designed as an “add-on” at the rear of an operation or sequence of operations

carried out by any soil tilling or planting machine. The self-cleaning properties of the Aqueel

make for simple and low cost applications avoiding the need for complicated and expensive

cleaning systems such as scrapers or brushes, etc. The Aqueel has combined two

historically opposed principles.A seed bed/soil with a low tilth index, which optimizes seedling

emergence, subsequent crop growth and ultimate yield; and soil surface roughness that can

increase the soil surface water storage with consequential soil surface water runoff and

erosion reduction.

Soil surface indentations created by the Aqueel can retain water. The simple wheel concept

applies pressure on the loose soil to firm and form mini reservoirs in between crop rows or on

the surface. These reservoirs internal surfaces are consolidated in such a way that the water

is held, to percolate into the soil, thus allowing time to offering the plant rooting zone moisture

over a extended period of time. Each indentation has a potential water storage capability of

approximately 1 liter, depending of the type of soil. The Aqueel can produce up to 192,500

indentations per hectare, which means a potential for retaining all rainwater from a 20 mm.h-1

storm even if no infiltration occurs. The creation of indentations in loose soil enables optimum

seedbed conditions for crop emergence and growth to be combined with a stable soil


structure capable of absorbing water efficiently at the high rates of rainfall in semiarid areas.

Historically, these two factors have generally been incompatible.

The Aqueel is manufactured of a material with unique elastomeric properties that “self

cleans”, which eliminates the need for any scraper system. The wheel is also long lasting and

with excellent abrasion resistance. The best work is done when the soil moisture content is

around the friable limit and can be used at any time the indentations are needed in the field

for water harvesting.

Under the integrated systems approach, a new RST system was developed and evaluated to

achieve maximum water harvesting and crop production. The integration of the system

considered the use of a deep tillage tool for seed bed/soil preparation with horizontal cutting,

known as the multiarado®, the use of a modified row planter for greater plant population and

the use of the Aqueel roller for water harvesting.

In this paper, all the designs and consideration for the integration of the new RST are

presented. Evaluation was performed in laboratory and field conditions to study the effect of

the system on soil erosion, runoff, soil moisture content and yield.

Methodology

Components of the New Reservoir Tillage System

Soil Preparation

The new Reservoir Tillage System was integrated using state of the art knowledge and

technology for soil preparation. The idea was to prepare the soil bed with no inversion of the

soil by means of a horizontal cutting instead of the vertical cutting that most of the subsoilers

or chisel plows do. A subsoiler was designed for this purpose. The new subsoiler,

commercially named as Multiarado® (translated as multiplow, Figure 1) operates at depth of

40-45 cm and leaves the soil bed ready for planting, which means no further disking or

leveling operations are needed.


Figure 1. Horizontal cutting tool for soil preparation. Not a scale design.

Planting Equipment

A conventional row planter was modified and converted from two to three rows for planting on

a high-rise bed arrangement. Traditionally, farmers use ridges and furrows separated around

76 cm. The modified planter allows planting of three rows 40 cm apart in a 152-cm bed

(Figure 2). This new topological arrangement increases the amount of seed planted by 50%,

which potentially will increase plant population and yields by the same percentage. The

number of seeds per line meter is adjusted to the local recommendations and in this

particular case a distance between plants of 15 cm was targeted.


152 cm

76 cm

40 cm

A

B

152 cm

76 cm

40 cm

A

B

Figure 2. Topological arrangement achieved with a traditional (A) and a modified planter (B).

The Aqueel Roller

A key component of the new Reservoir Tillage System is the plastic-made wheel,

commercially known as Aqueel . The Aqueel wheel makes a continuous row of

indentations that can be multiplied along an axle to make a roller. The Aqueel roller creates

indentations in the loose soil surface, which act as reservoirs for the storage of rainwater. The

Aqueel´s ability to create small indentations over the soil surface can result in as many as

192,500 indentations per hectare, each with a water capacity of up to 1 liter. The final volume

of these reservoirs is dependant upon the soil conditions at the surface being worked and the

expected rainfall intensity and duration. Speed of tractor is also a determinant factor.

The Aqueel has an outside diameter of 480 mm, inside diameter of 219 mm, a width of 115

mm and an average weight of 68 kg per meter (Figure 3).

An Aqueel roller was designed to fit the modified planter and to make indentations for “In

situ” rainwater harvesting after planting. The final design (Figure 4) consisted of 15 Aqueel

wheels with a working width of 150 cm


Figure 3. Aqueel wheel technical information.


Figure 4. Aqueel roller for “In situ” rainwater harvesting.

Because the Aqueel has been designed primarily as the last in a series of operations,

subsequent passes do not destroy the run off protection provided by the roller. However,

even in case where a further operation is performed after the roller has been used, some

benefit can still be seen. The creation of indentations in loose soil does not cause

compaction, which has a negative effect on water infiltration. It only consolidates the soil.


Additionally, because the indentation operation is normally the last of a sequence, the weight

of the unit becomes less important and it can therefore be considerably lighter than many

conventional rollers.

Evaluation of the System

Simulated rainfall laboratory experiments

The evaluation of the Aqueel was performed at the University of Queretaro Hydraulics

Laboratory at Queretaro, Mexico. Simulated rainfall was applied with a Norton-type

programmable Rainfall Simulator (Ventura, 1998). The soil used for evaluation was a heavy

clay vertisol representative of semiarid Central Mexico with very unique physical, mechanical

and hydraulic properties mostly due to the high clay content (about 60%) and the type of

dominant clay (swelling and shrinking smectite). The soil was sampled at field conditions and

let air-dry before passing it through an 8-mm sieve. The sieved soil was then packed in a

wooden box 3 m long 90 cm wide and 30 cm deep, set to a 5% slope, to a bulk density

similar to the one in the field. After packing of the soil, the Aqueel was used to create

indentations in the treated soil. A control with no indentations was also evaluated in a dry-

wet- very wet sequence of rain following the procedures recommended by Laflen et al.

(1987). A rainfall target intensity of 50 mm.h-1 was applied during 30 minutes for each

condition in the sequence. Runoff and sediment samples were taken every 5 minutes since

the beginning of the runoff and calculations of erosion and runoff using gravimetric methods

were obtained.

Simulated Rainfall Experiments using USLE plots.

The Simulated Rainfall experiment using USLE plot technology (Wischmeier and Smith,

1978) consisted of two side-by-side USLE plots. One plot corresponded to the control and the

second one was the Aqueel plot. The standard USLE plots to be evaluated were 6-m long

and 2-m wide and were located on a 7% slope near the University of Queretaro School of

Engineering. Simulated rainwater was applied with a sprinkler irrigation system at a target

rate of 50 mm.h-1 on a dry-wet-very wet rainfall simulation sequence according to the

procedures of Laflen et al. (1987). Actual rain intensity applied was 40 mm.h-1. Runoff and

sediment samples were collected every five minutes after initiation of runoff and later

processed to obtain soil erosion and runoff.


Field Evaluation

All the parts of the system were integrated and used with 3 cooperating farmers in the

semiarid area of the State of Queretaro, Mexico. The crop planted was common beans

(Phaseolus vulgaris L.). Five beans varieties were used and the cooperating farmers

recorded grain yield, at harvest time. Evaluation of soil moisture using TDR technology was

also measured at the end of the growing season.

Results and Discussion

Simulated rainfall laboratory and USLE plots experiments

According to the results obtained in the laboratory experiments, runoff started 15 minutes

after initiation of rainfall simulation in the control plot while, the runoff in the Aqueel

treatment started 35 minutes after the beginning of rainfall simulation (Figure 5). This 20

minutes delay in runoff initiation represents the Aqueel benefits in enhancing infiltration

during the first stages of rain. Runoff rate increased notable faster in the control as compared

to the Aqueel . At 40 minutes of simulation, the runoff rate in the control was about 40 mm.h-

1, while the corresponding value for the Aqueel was about 15 mm.h-1. The trend was to

similar values for both treatments during the last simulation for the very wet run. However,

total runoff for the 90 minutes simulation was reduced from 50 mm in the control to 35 mm in

the Aqueel treatment, totaling a 30% reduction. This also indicated a greater infiltration rate

for the treated plot.

Soil erosion was consistently lower in the Aqueel treatment as compared to the control.

Initial erosion rate at 35 minutes after initiation of simulation was in the order of 8 g of soil.m-

2.min-1, while the corresponding rate for the control at the same time was 24 g of soil.m-2.min-

1, which indicates that only one third of the soil erosion was occurring with this component of

the new RTS. Runoff and soil erosion were delayed and reduced significantly with the

Aqueel using simulated rainfall experiments in the laboratory. This is explained by the fact

that rainfall was collected in the minireservoirs allowing more time for infiltration, which

reduced runoff and its great potential to detach and transport soil particles when the Aqueel

was used. Detachment and transport by the concentrated flow is one of the main processes

involved in soil erosion (Foster and Meyer, 1975).


Run

off (

mm

/h)

10

20

30

40

50

ControlAqueel

Regression line

Time (minutes)0 20 40 60 80

Ero

sion

(g/m

2 /min

ute)

0

5

10

15

20

25

30

ControlAqueel

Regression line

Figure 5. Runoff and erosion as affected by the use of Aqueel impressions on a heavy clay soil from semiarid Central Mexico. Similar results were obtained when a simulated rain was applied on USLE plots using the

sprinkler irrigation system. With an applied rainfall intensity of about 40 mm.h-1, runoff

initiated 10 minutes from the beginning of simulation in the control plot, while it was delayed

in the Aqueel treated plot and occurred 30 minutes later (40 minutes from initiation of

simulation). Final runoff rate for the control plot was about 35 mm.h-1, while the

corresponding value for the Aqueel treatment was only about 5 mm.h-1. If we consider that

evaporation was not significant during the 60 minutes of continuous simulation, then the

estimated final infiltration rate for the control plot was about 5 mm.h-1, while the estimated

value for the treated plot was 35 mm.h-1, which represents an increase of about 30 mm.h-1.


As a direct response to the runoff produced in the plots, soil erosion was also significantly

higher in the control as compared to the treated plot. At steady state conditions of runoff,

which happened at the very wet condition, soil erosion rate averaged about 8 g of soil.m-

2.minute-1 in the control, while the corresponding value for the treated plot was about 4 soil.m-

2.minute-1. This 50% reduction in the amount of soil loss is a result of having a geometrically

ordered soil surface roughness created with the Aqueel , which reduces runoff rate and

velocity. Soil surface roughness is an important factor in preventing soil erosion (Eltz and

Norton, 1997).

The same USLE plots were use to evaluate soil erosion and runoff in natural rainfall

conditions. Under a heavy intense rainfall on August 1, 2002, runoff was very similar in both

plots, which indicates that for heavy storms and steep slopes the Aqueel impressions may

not work adequately to reduce the amount of water lost. This situation is only true when the

soil is shallow and becomes saturated, which was the case of our plot site. However, the

Aqueel managed to reduced soil erosion significantly (Figure 6). This indicates the positive

effect of the soil roughness created by the Aqueel and the reduction in runoff velocity, which

reduced detachment and transport capacity of the runoff.

Field Evaluation of the New System

Soil Preparation

Soil preparation was performed in the in the field using the designed Multiarado®. As a

comparison, different soil preparation tools were used and the distribution of soil aggregates

was evaluated as an indicator of a good soil preparation. Moldboard plowing created the

bigger aggregate clods on the soil surface layer (20 cm) while the Multiarado® and disk

harrow produced smaller size of clods. The combination of Multiarado® and Aqueel

improve soil tilth by decreasing the amount of clods greater than 10 cm from 22% to about

12%. Mean weight diameter (MWD) for the moldboard plow was 4.86 mm, while the

corresponding value for the Multiarado® and disk harrow was 3.81 and 4.34 mm,

respectively. The combination of Aqueel and Multiarado® reduced the MWD to 3.35 mm

and improved soil tilth by increasing the amount of small soil aggregates in the range of 1 to

about 5 mm (Figure 7).


Water infiltration evaluations were made using the double cylinder method in a conventional

tilled soil and a Multiarado® tilled soil. The Multiarado® increased the steady state infiltration

rate from 5.5 mm.h-1 in the conventional tillage to about 17 mm.h-1 in the Multiarado®

treatment (Figure 8).

P

reci

pita

tion

or R

unof

f (m

m.h

-1)

0

20

40

60

80

100

120

140

160PrecipitationRunoff ControlRunoff Aqueel

TIME (Fraction Hours)

7.5 8.0 8.5

Ero

sion

(g.m

-2.m

inut

e-1)

0

20

40

60

80

100

120Erosion ControlErosion Aqueel

Figure 6. Soil erosion and runoff generated from USLE-type plots during a heavy storm on

August 1, 2002. Time infraction hours means 7.5 is 7:30, in this case the time is Past

Meridian (PM).


Aggregate Size Diameter (mm)

0.1110

Per

cent

reta

ined

(%)

0

5

10

15

20

25

30

35

Moldboard Plow (MW D= 4.86 mm)

Disk Harrow (MW D= 3.81)

Multiarado + Aqueel (MW D= 3.35 mm)

Multiarado (MW D=4.34 mm)

Figure 7. Aggregate size distribution for different soil bed preparation tools in semiarid Central Mexico. Mean Weight Diameter (MWD) is in cm and vertical bars are 1 standard deviation for three replicates.

Time (minutes)0 10 20 30 40

Infil

tratio

n ra

te (m

m.h

-1)

0

20

40

60

80

100

120Multiarado Conventional

Figure 8. Infiltration rate in a soil bed prepared with the Multiarado® subsoiler and conventional moldboard plowing followed by disk harrowing.


Planting equipment

Final assembly of the roller to the row planter and the work it performed in one of the farms

evaluated can be observed in Figure 9a and 9b.

Aqueeled area

Improved soil tilth

(a)

(b)


Figure 9. Planter and roller assambled (a). Aqueel roller indentations (b) after planting. The minireservoirs created by the Aqueel roller harvested almost 100% of the rainfall in the

area and there was no significant evidence of runoff on the field plots. The picture in Figure

10 shows the minireservoirs actually working during a rain on July 14, 2002.

Figure 10. Water harvesting using the new RST in a farm planted with beans in semiarid Central Mexico. Actual rain occurred on July 14, 2002 with an average intensity of 25 mm.h-1. No runoff or soil erosion occurred during this is rain on the farms were the new system was

used. Evidences of large amounts of runoff and erosion were observed in conventional

planted farms that served as control, but no evaluations were made. The area exposed to the

impact of raindrops is significantly reduced once the imprints start to fill with water. This

reduces the impact of raindrops and consequently the soil surface sealing is reduced

significantly. About 50% of the soil surface area is protected by the water harvested, which

dissipates the energy of impact caused by falling raindrops, as can be observed in Figure 10.


After July 14, 2002, there no rain was recorded rain in the area until September 6, 2002.

Several farms planted with beans, including the reference plots, suffered form the long

drought. However, the use of the Multiarado® subsoiler for soil preparation and the Aqueel

for water harvesting at planting time allowed enough infiltration from previous rains, which

helped the plants to survive, with no significant evidences of drought effect (Figure 11).

Figure 11. Beans growing in a field with the managed with the new RTS. No rain was recorded since July 14, 2002 in the study area. The picture was taken on August 23, 2002. Next rain fall in the area on September 6, 2002. The higher soil moisture content in the farms with the new reservoir tillage system allowed

the crop to grow during the drought period and increased the potential for a greater yield.

Harvesting was done in October. The final grain yields for five different varieties of beans can

be observed in Figure 12. The new RTS increased grain yield from an average of 450 kg.ha-1

in the reference conventionally tilled plots to about 900 kg.ha-1 in the plots with the new

system, which means an increase of about 100%. It is important to mention that some

farmers in the area did not harvest any beans due to the severity of the drought.


Soil moisture was measured after harvesting to evaluate water storage in the treated and

conventional plots. From the soil surface down to 40 cm, volumetric soil moisture content was

greater with the new system as compared to the conventional system (Figure 13). Average

soil moisture content in the conventional system from 0-40 cm was 22% while the

corresponding value for the new system was 42%.

In semiarid areas, soil preparation is made during the driest periods of the year, which means

the use of greater amount of fuel, power, time and more rapid deterioration of the equipment.

We recommend to take advantage of the moisture condition of the soil at harvest time and

use the Multiarado® and the Aqueel roller together for soil preparation at this time. This will

prepare the seed bed for next growing season and will also break the continuity of

evaporation, which in turn will help conserve soil for a longer period of time. Soil preparation

will be accomplished earlier and only in one pass. This eliminates the use of moldboard

plowing and disk harrowing, while preserving soil moisture. Indentations created with the

Aqueel® will form a soil roughness that may probably help also in reducing wind erosion

during the dry season. A first prototype of a unit with the Multiarado® and the Aqueel can

be observed in Figure 14.

Gra

in Y

ield

(Kg/

ha)

0

200

400

600

800

1000

1200

New System Conventional

Figure 12. Grain yield in common beans with the new system and the conventional system

used in semiarid central Mexico.


Volumetric Moisture Content (%)0 10 20 30 40 50 60 70 80

SO

IL D

EP

TH (c

m)

30-40

20-30

10-20

0-10ConventionalNew System

Figure 13. Soil moisture content at different depths with the conventional and the new RTS.

Figure 13. Combination of a Multiarado® subsoiler and an Aqueel roller for soil preparation.

Conclusions

A new integrated Reservoir Tillage System (RST) was developed and evaluated for crop

production in semiarid areas. The system consisted in the use of a horizontal-cut subsoiler for


seedbed preparation, a modified row planter to achieve higher plant populations and a

unique technology for water harvesting that consisted of a roller made of plastic wheels.

In field evaluations, the new system eliminated the need of disk plowing and harrowing for

soil preparation when used in moist soil. Runoff and erosion were significantly reduced and

infiltration of water into the soil was increased with the new system, according to the

evaluations made in the laboratory runoff-erosion plots with simulated and natural rain. In he

field, areas where the new RTS was used had a grater soil moisture content allowing the crop

to stand long periods of drought. The final grain yields of beans were increased in about

100%. Two parts of the system, the Multiarado® and the Aqueel can be combined together

for soil preparation immediately after harvesting time. A soil prepared during this time will

conserve more moisture and the roughness created by the implements will reduce the

negative effects of wind erosion during the long subsequent dry season.

Acknowledgements

The authors want to acknowledge Fundación Produce Quretaro A.C. for the financial and

logistic support in favor of this study.

Disclaimer

The use of trade or registered names is for the readers and does not mean an endorsement

of the USDA or the University of Queretaro.

References Aarstad, J.S. and D.E. Miller, 1973. Soil management to reduce runoff under center-pivot

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