AGRICULTURE AGENT UPDATE

NORTHERN AG. RESEARCH CENTERHAVRE, MONTANA

 JUNE 27, 2013

Soils 101Relative to Crop Production

in Montana

Olga WalshAssistant Professor, Soil Nutrient ManagementWestern Triangle Agricultural Research Center

Montana State University

OUTLINE

Soils: Definition Soil profile Soil texture MT soils

Soil productivity: Soil sampling Nutrients ant plant growth Mobile vs Immobile MT deficiencies/toxicities Fertilizer Strategies

SOIL DEFINED

“(i) The unconsolidated mineral or organic material on the immediate surface of the Earth that serves as a natural medium for the growth of land plants

(ii) The unconsolidated mineral or organic matter on the surface of the Earth that has been subjected to and shows effects of genetic and environmental factors of: climate (including water and temperature effects), and macro- and microorganisms, conditioned by relief, acting on parent material over a period of time.

A product-soil differs from the material from which it is derived in many physical, chemical, biological, and morphological properties and characteristics.”(NRCS, 2013)

SOIL DEFINED

“Soil is a natural body comprised of solids (minerals and organic matter), liquid, and gases that occurs on the land surface, occupies space, and is characterized by one or both of the following: horizons, or layers, that are distinguishable from the initial material as a result of additions, losses, transfers, and transformations of energy and matter or the ability to support rooted plants in a natural environment.”(Soil Taxonomy)

SOIL IS A DYNAMIC BIOGEOCHEMICAL INTERFACE BETWEEN THE EARTH’S SPHERES

12 SOIL TYPES12 basic types of soils – soil orders reflect environment in which they form, their age, and the ecosystem they support

NRCS, 2013

Scobey

MT PREDOMINANT SOILS Mollisols: form in

semi-arid to semi-humid areas, typically under a grassland cover

Alfisols: form in semiarid to humid areas, typically under a hardwood forest cover

Entisols: young soils, do not show any profile development other than an A horizon. unaltered from their parent material, which can be unconsolidated sediment or rock.

Inceptisols: weakly developed, one or more subsurface horizons, contains many unweathered minerals; form quickly through alteration of parent material; older than entisols; have no accumulation of clays, iron oxide, aluminium oxide or organic matter.

NRCS, 2013

SOIL PROFILE

soils.wisc.edu, 2013

COMPARISON OF MT’S PREDOMINANT SOILS

A – maximum accumulation of humusE – zone of maximum weathering and leaching (elluvial)B – zone of maximum accumulation and alteration (illuvial)• Bw – almost no

clay• Bt – more clay

C – zone of minimal accumulation, alteration and cementation

SCOBEY – MT STATE SOIL

Scobey = Mollisol Surface layer:  very dark grayish brown

clay loam; Subsurface layer:  dark brown clay; Subsoil:  dark grayish brown clay loam

Very deep, well drained soils on till plains, hills, and moraines in the north-central MT

>700,000 acres, among most productive soils in MT Golden Triangle (Havre-Conrad-GF): dryland winter and spring wheat

Formed in glacial till and under prairie vegetation

Av. annual precipitation ~ 12 in; av. annual air temperature ~ 43 F; 115 frost free days

Named for the town of Scobey, in NE MT. NRCS, 2013

MOLLISOL

From Latin word “Mollis”, meaning soft These mineral soils developed on grasslands, a

vegetation that has extensive fibrous root systems.

The topsoil of Mollisols is characteristically dark and rich with organic matter, giving it a lot of natural fertility

Typically well saturated with basic cations (Ca2+, Mg2+, Na+, and K+) that are essential plant nutrients

Among the most fertile soils found on Earth

SOIL TEXTURE Refers to the size of the particles that make up the soil

2 – 75 mm

> 75mmRock

Very fine: 0.05 - 0.1 mmFine: 0.1 - 0.25 mm

Medium: 0.25 - 0.5 mmCoarse: 0.5 – 1 mm

Very coarse: 1 -2 mm

0.002 to 0.05

< 0.002

SOIL TEXTURE

% Clay % Silt % Sand Texture

15 70 15 Sandy Loam

http://courses.soil.ncsu.edu/resources/physics/texture/soiltexture.swf

SOIL TEST

AgVise, 2013

“Soil testing is the best tool available to determine the amount of each nutrient needed for the coming crop year”

Soil testing is the best tool available to determine the amount of each nutrient present in the soil from the previous crop year

SOIL TESTING

Soil probe allows a uniform slice of the soil profile to any depth.

Depths: 0-6" and 6-24", to 48“ for deep-rooted crops (sugarbeet)

Time: P, K, pH, %OM, salts, Ca, Mg, Zn,Fe, Mn, and Cu - any time of the year (minor changes)

Time: N, S, Cl - in the fall following harvest or early spring

Sample storage: cool, frozen or send to the lab immediately

AgVise, 2013

SOIL SAMPLING METHODS

15-20 soil cores torepresent a field The cores are mixed and a portion is sent to the lab Avoid non-representative areas Provides average soil nutrient level in each field Can result in under- orover- estimation

Field split intoproductivity zones (satellite canopy images, yield maps, salinity maps, soil type maps, topography, etc.) Representative sample (10-15 cores) from each zone Soil nutrient levels in each zone can be quite different

Field split into small equal sized areas (1 - 5 acres) 8-10 cores collected from the center of each grid or randomly within the grid Nutrient levels are determined for each grid Fertilizer recommendations – for each grid

AgVise, 2013

NUTRIENTS AND PLANT GROWTH

o Plant’s sufficiency range = range of nutrient necessary to meet plant’s nutritional needs and maximize growth

o Nutrient levels outside of a plant’s sufficiency range cause crop growth and health to decline due to either a deficiency or toxicity

Mc Cauley et al., 2009

MOBILE AND IMMOBILE NUTRIENTS

BLA BLA

BLA BLA

Roger Bray, “A Nutrient Mobility Concept or Soil-Plant Relationships. 1954. Soil Science.

MT SOILS:COMMON DEFICIENCIES /TOXICITIES

Most common: N and P Sometimes – K, S

Micronutrient deficiencies are fairly uncommon with deficiencies of B, Cl, Fe, and Zn occurring most often

Toxicities – uncommon, result of over-fertilization

ESSENTIAL PLANT NUTRIENTS

Total of 16 essential nutrients

3 Macronutrients from air and water: Carbon, Hydrogen, Oxygen (C, H, O)

13 MACROnutrients from soil:3 Primary nutrients - Nitrogen, Phosphorus

and Potassium (N, P, K)3 Secondary nutrients - Calcium, Magnesium

and Sulfur (Ca, Mg, S)7 MICROnutrients - Iron, Manganese, Zinc, Copper, Boron, Molybdenum, and Chlorine (Fe, Mn, Zn, Cu, B, Mo, Cl)

ESSENTIAL PLANT NUTRIENTS

Deficiency disrupts plant’s growth and reproduction

Deficiency can be prevented or corrected only by supplying the element

Nutrient is directly involved in the nutrition of the plant

YIELD POTENTIAL AND FERTILIZER

Q 1. Which field has a higher Yield Potential?Q 2. Which field needs more fertilizer?

Field A Field B

“BLANKET” VS PRECISION

Conventional application of N – one rate based on average needs of the field/fields

Variability in production potential(natural, acquired, spatial, temporal) Average rate is excessive in some parts and

inadequate in others Precision Agriculture = timely and precise N

application to meet plant needs as they vary across the landscape

Sensor-Based Technologies – precision agriculture tools, allow to account for variability and to make more informed decisions

PRECISION AGRICULTURE AND NUE

• Yield Potential approach: No guess-work Minimizes producer’s risks Higher NUE

• Precision N Fertilization entails: Right time and Right rate They vary across the field to meet plants’

needs

• Sensor-Based Technologies – precision agriculture tools, allow to account for all types of variability and to make more informed decisions

YIELD GOAL VS YIELD POTENTIAL

Yield Goal: Average yield for past 5 years + 30% (just in case we

have a good year) Based on past (historical data) Uses average N rates

Yield Potential:

Estimated using in-season data Based on current crop nutrient status Precise N rate (crop- and site-specific)

YIELD GOAL VS YIELD POTENTIAL

Yield Goal Sufficiency approach: to apply a fixed rate of N at

a computed sufficiency level, regardless of YP

Yield Potential: Estimates of YP and crop response to N provide aphysiological basis to estimate N removal and a biologically based N application rate

Tabitha, WSU

YIELD POTENTIAL VARIES YEAR TO YEAR

1940 1950 1960 1970 1980 1990 2000 2010 20200

20

40

60

80

100

120

140

160

180

200

“Maximum Attainable Yield” (Yield Goal)

ActualHarvested

Yield

Should we fertilize for maximum yield every year?Alternative to Yield Goal - Yield Potential

Source: Taylor, 2009

Yield Potential Prediction

The concept of sensing biomass in various crops

Biomass used as an indicator of nutrient need

Knowing how much biomass is produced => knowing how much N is removed from the soil and converted into biomass

Removal of N in harvested biomass and grain is highly correlated with yield

YIELD POTENTIAL AND RESPONSE TO N YP and RI are independent from one another:

High YP, High RI

High YP, Low RI

Low YP, High RI

Low YP, Low RI

Field A Field B

PRECISION SENSOR’S BASICS

Emits light and measures reflectance from plantsSensor reading - Similar to a plant physical

examinationSensor can detect: • Plant Biomass

• Plant Chlorophyll• Crop Yield• Water Stress• Plant diseases, and• Insect damage

CONCEPT SUMMARY

1. How much biomass is produced ?

2. What Yield is attainable without addition of N?

3. How responsive is the crop to N?

4. What Yield is attainable with addition of N?

YPN = INSEY*RI

NDVI = (NIR-red)/(NIR+red)

INSEY = NDVI/GDD>0

RI = NDVI (NRS) /NDVI (FP)

Marty Knox is obtaining winter wheat canopy reflectance data using GreenSeeker optical sensor, WARC, Corvallis, MT, May 2013

red

redNIR

NIR

30%50%

60% 8%

NDVI = (NIR-red)/(NIR+red)

NDVI (1) = (0.60 - 0.08)/(0.60 + 0.08) = 0.76NDVI (2) = (0.50 - 0.30)/(0.50 + 0.30) = 0.25

(1)

(2)

CONCEPT SUMMARY

1. How much biomass is produced ?

2. What Yield is attainable without addition of N?

3. How responsive is the crop to N?

4. What Yield is attainable with addition of N?

YPN = INSEY*RI

NDVI = (NIR-red)/(NIR+red)

INSEY = NDVI/GDD>0

RI = NDVI (NRS) /NDVI (FP)

VARIABLE RATE IN MONTANA“Sensor-based VRT saves fertilizercosts, improves crop production” By Shannon Ruckman, The Prairie Star editor;

2008Herb OehlkeFarms Wheat and Barley, since1995 Ledger, 20 min from ConradSwitched from blanket to

variable-rate applicationSaved money and timeUses GreenSeeker on all his

wheat fields

VARIABLE-RATE IN MONTANA

“I really questioned if it would work” “I wanted to know if it would work with the

NRCS requirements”“I can't under apply fertilizer, but I need to

be more efficient at it. Net return is an important number.”

Saved 5.3 gallons of fertilizer per acreAchieved 8 to 10 bus/ac increase in yield“Had average yield- 57 bus/ac. The VRT

fields yielded 67 to 70 bus /ac. At $10/bu, that adds up real fast. That’s $100 /ac!”

THANK YOU!QUESTIONS?

ADDITIONAL SLIDES ONNUTRIENT ROLE/ DEFICIENCY

MACRONUTRIENTS

NUTRIENTS FROM AIR AND WATER

Carbon, Hydrogen, Oxygen

Base of all organic molecules, building blocks for growth Absorbed as CO2

Combined with H and OTransformed into carbohydrates in leaves in the process of photosynthesis

ESSENTIAL MACRONUTRIENTS

N, P, K

Needed in greater amounts for growth

Lacking from soil firstGreater response

N DEFICIENCY Light green upper (young) leavesYellow lower (older) leaves

ESSENTIAL MACRO NUTRIENTS: P Catalyses biochemical reactions

Component of DNA (genetic memory)

Component of energy molecules Key element in photosynthesis

P DEFICIENCY Dark purple discoloration on the leaf tips, advancing down the leafStunted plants with fewer shoots

ESSENTIAL MACRO NUTRIENTS: K

Photosynthesis and movement of nutrients

Protein synthesis

Activation of plant enzymes

Regulation water use

K DEFICIENCY

Marginal chlorosis and necrosis on older leavesShorter internodes, stunting

ESSENTIAL SECONDARY NUTRIENTS

Ca, Mg, S

Needed in moderate amounts

ESSENTIAL SECONDARY NUTRIENTS: CA

Cell structure, membranes

Nutrient uptake

Reaction to negative environmental factors

Defense against disease

CA DEFICIENCY Poor root growth, stunted dark rotting rootsSymptoms – in new growth (necrotic spots in young leaves), leaves collapse before unrolling

ESSENTIAL SECONDARY NUTRIENTS: MG

Chlorophyll formation

Light-absorbing pigments

Amino acids and proteins

Resistance to drought and disease

MG DEFICIENCY

Pale green, chlorotic young leavesFolded or twisted leavesSymptoms similar to drought

ESSENTIAL SECONDARY NUTRIENTS: S

Component of amino acids and proteins

Component of enzymes and vitamins

Formation of Chlorophyll

S DEFICIENCY

Seedlings: pale yellow chlorosis on young leaves

S deficient leaf (left) normal

(right)

MICRONUTRIENTS

MICRONUTRIENTS

Fe, Mn, Zn, Cu, B, Mo, Cl

Needed in very small amounts

Involved in metabolic reactions as part of enzymes (reused, not consumed) Can be corrected with a fraction of pound per acre rate

IRON (FE)

RespirationPhotosynthesisEnzymatic ActivatorChlorophyll Synthesis

FE DEFICIENCY

Failure to produce sufficient chlorophyll Interveinal chlorosis, green/yellow stripes New leaves turn white

MANGANESE (MN)

Component of various enzyme systems for:

energy productionprotein synthesis, andgrowth regulation

MN DEFICIENCY

Interveinal chlorosis Brown necrotic spots on leavesWhite/gray spots on leaves Premature leaf drop and delayed maturity

ZINC (ZN)

RespirationPhotosynthesisEnzymatic ActivatorChlorophyll Synthesis

ZN DEFICIENCY

First appear on middle-aged and old leavesMuddy gray-green leaf colorLeaves appear drought stressed, with necrotic spots

COPPER (CU)

Catalyst in photosynthesis and respiration

Constituent of enzymes Involved in building and converting

amino acids to proteins Carbohydrate and protein

metabolism Plant cell wall constituent

CU DEFICIENCY

Leaf tip die-back followed by a twisting or wrapping of the leaves Delayed maturity Stunted, misshapen heads

BORON (B)

Cell wall strength and development

Cell divisionFruit and seed developmentSugar transport

B DEFICIENCY

Saw tooth effect on younger leavesPale, “water-soaked” new shootsHead sterility

MOLYBDENUM (MO)

Conversion of nitrates (NO3 ) into amino acids in the plant

Conversion of inorganic P into organic forms in the plant

Protein synthesisSulfur metabolism

MO DEFICIENCY Stunted plantsFlowering/Seed formation affectedHollow stemsBrittle, discolored leaves

CHLORIDE (CL)

Photosynthesis

Stomata regulation

Gas and water balance in cells

Nutrient transport (K, Ca, Mg)

Disease resistance

CL DEFICIENCY

Physiological Leaf Spot SyndromeWhite to brown spots on leavesStarts in lower leaves at tilleringSimilar to tan spot, smaller spots, no “halo”

MICRONUTRIENT DEFICIENCY

High soil pH (uptake decreases as pH increases) – all but MoMT typical pH = 7-8, varies from 4.5 to 8.5

Low organic matter MT typical OM = 1-4%

Cool, wet weather

MICRONUTRIENT PRODUCTS

Citri-Che Crop Mix 1 (N, S, Cu, Mn, Zn)Gainer High Phos (N Nitrogen, Phosphate, Potash, Sulfur, Boron, Copper, Iron, Manganese, Molybdenum and Zinc