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