Nutrients
160 140 120 100 Potash Phosphate Nitrogen 80 60 40 20 0 1961 1971 1981 1991 2001 2011 Year FAOSTAT
45,000,000 40,000,000 35,000,000 30,000,000 25,000,000 20,000,000 15,000,000 10,000,000 5,000,000 0 China USA India Brazil France Indonesia Pakistan Canada N P K
Macro Nutrients Nitrogen (N) Phosphorous (P) Potassium (K) Calcium Magnesium Sulfur Micro Nutrients Boron Iron Copper Nickel Chlorine Zinc Manganese
Organic matter, measured as a % of total soil. Humic matter content: The relatively stable fraction of organic matter is called humic (humus) matter, which comprises 60-80% of the actual organic matter of the soil. Weight per volume: class or soil (gm/cm 3 ). 1.5+ = high sand; 1.0 = silt/clay loam; less than 0.4 = high organic matter. Cation Exchange Capacity: soils rich in organic matter & clay) hold more cations (Ca 2+, K +, Mg 2+ ). Soils with low CEC are susceptible to leaching. ph: is used to determine the need to apply lime.
Most useful with a representative and uniform soil samples. Depth of sample One foot increments. One foot for non-mobile nutrients, such as P & K. Deeper for nitrate nitrogen, depends on field/crop. Sample through the field to avoid sampling effects. Once collected, air-dried to avoid changes in NO 3 - nitrogen as a result of microbial activity. Sample as close to planting as is feasible.
Depth: One foot increments Keep different depths separate How Deep? Soil Depth. Rooting depth of crop to be planted. One foot for most nutrients. Immobile nutrients (positive ions and phosphate). Micronutrients. Deeper for nitrate. Two or three feet is common.
Element Low Optimum High ------------------- ppm ------------------- Nitrogen 0-30 31-60 60 + Potassium 0-60 61-120 120 + Phosphorus 0-11 12-15 15 + Magnesium 0-60 60-120 120 + Calcium 0-800 800-1,200 1,200 +
Nitrogen is the key nutrient in plant growth. Nitrogen stimulates leaf and stem growth. Component of proteins, nucleotides, enzymes and alkaloids. 40-50% of protoplasm. Mobile in plants so deficiency symptoms show first on old leaves.
Soil nitrogen is derived from mineral, atmospheric and organic sources. As rocks decompose through weathering nitrogen is released. Decomposition of organic remains by soil microbes releases the organic nitrogen into inorganic forms. This is called mineralization.
Plants can absorb nitrogen as either nitrate anion (NO 3- ) or ammonium cation NH 4+. Ammonium is subject to microbial transformation into nitrate. Ammonium (NH 4+ ) attaches to negatively charged anion sites available on soil clay and humus particles. Nitrates are readily leached in the soil while ammonium is not.
Nitrogen Movement N 2 O and N 2 Addition s Manures, sludge's, plant remains, other organic wastes Fertilizers, rain, snow, ammonia Denitrofication Soil organic matter NH 4 + and NO 3 - NO 3 - Nitrification NH 4 + Leaching
Nitrogen deficiency causes reduced growth, pale yellowish green leaves and reduced yield. The older leaves turn yellowish first since nitrogen is readily moved from the old leaves to the new growth. If the soil is cold and wet, nitrogen in the soil is not as available to the plants.
N-Deficiency
Interpreting Nitrogen Soil Test Results Depth (inches) Soil Test Results Factor Total NO 3 NH 4 Total 0 to 12 inches 5 1 6 x 3.5 = 21 12 to 24 inches 4-4 x 3.5 = 14 24 to 36 inches 3-3 x 3.5 = 10.5 Total 12 1 13 x 3.5 = 45.5 Ammonium (NH 4 -N) is usually low and is often not included in the soil test analyses. Conversion factor = x 3.5 = lb/acre.
Total Nitrogen Needed for Annual Precipitation (inches) Optimum Wheat Crops Total N Spring Total N Winter 21 inches or less 2.3 x Yield (bu/a) 2.5 x Yield (bu/a) 22 to 24 inches 2.4 x Yield (bu/a) 2.6 x Yield (bu/a) More than 24 inches 2.5 x Yield (bu/a) 2.7 x Yield (bu/a) Hard red wheat (14% protein) requires between 3.1 and 3.5 lb N /bu of wheat harvested.
Mineralized Nitrogen Released Soil Organic Matter Content N Contribution % lb/ac < 0.5 0.5-1.0 1.0-1.5 1.5-2.0 >2.0 10 15 20 25 30
Nitrogen for Straw Breakdown Residue Nitrogen to be added Tons 0 1 2 3 4 lb/acre One ton of residue is produced from each 20 bu of wheat harvested. 0 15 30 45 50
In spring wheat with a potential yield of 100 bushels per acre, annual precipitation of 23 inches, 2.3 % organic matter (conventional tillage), 2 tons of straw residue, and soil test values as in the soil test above (i.e. 45.5 units). Then: Total nitrogen needed = 100 x 2.6 = 260 lb/n/acre. Nitrogen needed for straw breakdown = +30 lb/n/acre. Minus mineralized nitrogen = -46 lb/n/acre. Minus soil test data = -45.5 lb/n/acre. Equals nitrogen required = 260+30-46-45.5 =198.5 lb/n/acre.
Fertilizer Formula % N/unit Anhydrous ammonia NH 3 88 Urea CO(NH 2 ) 2 45 Ammonium nitrate NH 4 NO 3 33 Urea ammonium nitrate solution - 30 Ammonium sulfate (NH 4 ) 2 SO 4 21 (+24% S) Potassium nitrate KNO 3 13 (+26%K)
Anhydrous has highest available nitrogen per unit (82%). Applied by specialist equipment to inject into soil. Seal immediately to avoid volatilization. Urea also susceptible to volatilization, hence not suitable for surface application. Ammonium nitrate is easy to apply but can cause fertilizer burn. Ammonium sulfate is recommended where S is deficient. UAN solutions are commonly used on winter wheat.
Phosphorus is important for germination and growth of seeds, the production of flowers and fruit, and the growth of roots. Component of nucleotides, phospholipids, enzymes, and ATP. Synthesis of carbohydrates and proteins. Mobile in plants so deficiency symptoms show first on old leaves.
Phosphorus deficiency causes reduced growth and small leaves that drop early, starting with the oldest leaves. Leaf color is a dull, bluish green that becomes purplish or bronzy. Leaf edges often turn scorched brown. Very mobile so symptoms show on old leaves first.
P-Deficiency
Fertilizer Formula % P/unit Triple superphosphate P 2 O 5 20 (+2%S) Single superphosphate P 2 O 5 8 (+11%S, 20%Ma) Mono-ammonium phosphate NH 4 H 2 PO 4 22 (+11%N) Di-ammonium phosphate (NH 4 ) 2 HPO 4 21 (+20%N) Phosphate rock Ca 3 (PO 4 ) 2.Ca X 8-18 (+30%Ca)
Phosphorus Requirements for PNW Wheat Soil test P Application Rates 0-12 inches P 2 O 5 P ppm -------- (lb/ac) -------- 0-3 4-7 8-11 over 12 160 120 60 0 70 53 26 0 P 2 O 5 x 0.44 = P P x 2.29 = P 2 O 5
Potassium promotes general plant vigor, enhances disease resistance and sturdy growth. Functions as an enzyme cofactor to regulate photosynthesis. Regulates carbohydrate translocation and protein synthesis. Very mobile in plants.
Potassium promotes general plant vigor, enhances disease resistance and sturdy growth. Potassium deficiency causes stunted growth with leaves close together. Starting with the older leaves, the leaf tips and edges turn scorched brown and leaf edges roll. Can result in crop lodging.
K-Deficiency
Fertilizer Formula % K/unit Potassium chloride KCl 56 Potassium sulfate K 2 SO 4 42 Potassium magnesium sulfate K 2 SO 4 MgSO 4 10 (+ 9% Mg, 18%S) Potassium nitrate KNO 3 37 (+11% N)
Potassium Requirements for PNW Wheat K soil test Potassium rates 0-12 inches K 2 O K ppm -------- lb/ac -------- 0-21 22-45 46-68 over 68 240 160 80 0 200 133 66 0 K 2 O x 0.84 = K K x 1.20 = K 2 O
Sulfur is an ingredient in proteins and is necessary for chlorophyll formation. Sulfur deficiency causes slow growth with small round leaves that roll upward and are stiff and brittle. Leaves drop off and tip buds die. Immobile in plants.
S-Deficiency
Sulfur Soils low in S (less than 10 ppm SO -2 4 in the plow layer or 8 ppm in the top 12-inch) should receive 20 to 40 lbs S/acre. Fields irrigated with Snake river water should not be deficient.
70 60 59% 50 47% 40 30 20 19% 25% 22% 28% 10 0 After Planting Before/at Planting Fall Before/at Planting Spring
Fertilizer placement
Nitrogen is the key nutrient in plant growth. Nitrogen stimulates leaf and stem growth. Component of proteins, nucleotides, enzymes and alkaloids. 40-50% of protoplasm. Mobile in plants so deficiency symptoms show first on old leaves.
Soil nitrogen is derived from mineral, atmospheric and organic sources. As rocks decompose through weathering nitrogen is released. Decomposition of organic remains by soil microbes releases the organic nitrogen into inorganic forms. This is called mineralization.
Plants can absorb nitrogen as either nitrate anion (NO 3- ) or ammonium cation NH 4+. Ammonium is subject to microbial transformation into nitrate. Ammonium (NH 4+ ) attaches to negatively charged anion sites available on soil clay and humus particles. Nitrates are readily leached in the soil while ammonium is not.
Nitrogen Movement N 2 O and N 2 Addition s Manures, sludge's, plant remains, other organic wastes Fertilizers, rain, snow, ammonia Denitrofication Soil organic matter NH 4 + and NO 3 - NO 3 - Nitrification NH 4 + Leaching
Nitrogen deficiency causes reduced growth, pale yellowish green leaves and reduced yield. The older leaves turn yellowish first since nitrogen is readily moved from the old leaves to the new growth. If the soil is cold and wet, nitrogen in the soil is not as available to the plants.
N-Deficiency
Interpreting Nitrogen Soil Test Results Depth (inches) Soil Test Results Factor Total NO 3 NH 4 Total 0 to 12 inches 5 1 6 x 3.5 = 21 12 to 24 inches 4-4 x 3.5 = 14 24 to 36 inches 3-3 x 3.5 = 10.5 Total 12 1 13 x 3.5 = 45.5 Ammonium (NH 4 -N) is usually low and is often not included in the soil test analyses. Conversion factor = x 3.5 = lb/acre.
Total Nitrogen Needed for Annual Precipitation (inches) Optimum Wheat Crops Total N Spring Total N Winter 21 inches or less 2.3 x Yield (bu/a) 2.5 x Yield (bu/a) 22 to 24 inches 2.4 x Yield (bu/a) 2.6 x Yield (bu/a) More than 24 inches 2.5 x Yield (bu/a) 2.7 x Yield (bu/a) Hard red wheat (14% protein) requires between 3.1 and 3.5 lb N /bu of wheat harvested.
Mineralized Nitrogen Released Soil Organic Matter Content N Contribution % lb/ac < 0.5 0.5-1.0 1.0-1.5 1.5-2.0 >2.0 10 15 20 25 30
Nitrogen for Straw Breakdown Residue Nitrogen to be added Tons 0 1 2 3 4 lb/acre One ton of residue is produced from each 20 bu of wheat harvested. 0 15 30 45 50
In spring wheat with a potential yield of 100 bushels per acre, annual precipitation of 23 inches, 2.3 % organic matter (conventional tillage), 2 tons of straw residue, and soil test values as in the soil test above (i.e. 45.5 units). Then: Total nitrogen needed = 100 x 2.6 = 260 lb/n/acre. Nitrogen needed for straw breakdown = +30 lb/n/acre. Minus mineralized nitrogen = -46 lb/n/acre. Minus soil test data = -45.5 lb/n/acre. Equals nitrogen required = 260+30-46-45.5 =198.5 lb/n/acre.
Fertilizer Formula % N/unit Anhydrous ammonia NH 3 88 Urea CO(NH 2 ) 2 45 Ammonium nitrate NH 4 NO 3 33 Urea ammonium nitrate solution - 30 Ammonium sulfate (NH 4 ) 2 SO 4 21 (+24% S) Potassium nitrate KNO 3 13 (+26%K)
Anhydrous has highest available nitrogen per unit (82%). Applied by specialist equipment to inject into soil. Seal immediately to avoid volatilization. Urea also susceptible to volatilization, hence not suitable for surface application. Ammonium nitrate is easy to apply but can cause fertilizer burn. Ammonium sulfate is recommended where S is deficient. UAN solutions are commonly used on winter wheat.
Phosphorus is important for germination and growth of seeds, the production of flowers and fruit, and the growth of roots. Component of nucleotides, phospholipids, enzymes, and ATP. Synthesis of carbohydrates and proteins. Mobile in plants so deficiency symptoms show first on old leaves.
Phosphorus deficiency causes reduced growth and small leaves that drop early, starting with the oldest leaves. Leaf color is a dull, bluish green that becomes purplish or bronzy. Leaf edges often turn scorched brown. Very mobile so symptoms show on old leaves first.
P-Deficiency
Fertilizer Formula % P/unit Triple superphosphate P 2 O 5 20 (+2%S) Single superphosphate P 2 O 5 8 (+11%S, 20%Ma) Mono-ammonium phosphate NH 4 H 2 PO 4 22 (+11%N) Di-ammonium phosphate (NH 4 ) 2 HPO 4 21 (+20%N) Phosphate rock Ca 3 (PO 4 ) 2.Ca X 8-18 (+30%Ca)
Phosphorus Requirements for PNW Wheat Soil test P Application Rates 0-12 inches P 2 O 5 P ppm -------- (lb/ac) -------- 0-3 4-7 8-11 over 12 160 120 60 0 70 53 26 0 P 2 O 5 x 0.44 = P P x 2.29 = P 2 O 5
Potassium promotes general plant vigor, enhances disease resistance and sturdy growth. Functions as an enzyme cofactor to regulate photosynthesis. Regulates carbohydrate translocation and protein synthesis. Very mobile in plants.
Potassium promotes general plant vigor, enhances disease resistance and sturdy growth. Potassium deficiency causes stunted growth with leaves close together. Starting with the older leaves, the leaf tips and edges turn scorched brown and leaf edges roll. Can result in crop lodging.
K-Deficiency
Fertilizer Formula % K/unit Potassium chloride KCl 56 Potassium sulfate K 2 SO 4 42 Potassium magnesium sulfate K 2 SO 4 MgSO 4 10 (+ 9% Mg, 18%S) Potassium nitrate KNO 3 37 (+11% N)
Potassium Requirements for PNW Wheat K soil test Potassium rates 0-12 inches K 2 O K ppm -------- lb/ac -------- 0-21 22-45 46-68 over 68 240 160 80 0 200 133 66 0 K 2 O x 0.84 = K K x 1.20 = K 2 O
Sulfur is an ingredient in proteins and is necessary for chlorophyll formation. Sulfur deficiency causes slow growth with small round leaves that roll upward and are stiff and brittle. Leaves drop off and tip buds die. Immobile in plants.
S-Deficiency
Sulfur Soils low in S (less than 10 ppm SO -2 4 in the plow layer or 8 ppm in the top 12-inch) should receive 20 to 40 lbs S/acre. Fields irrigated with Snake river water should not be deficient.
Calcium is a major ingredient in cell walls and is important for root growth, especially root tips. Calcium deficiency causes poorly developed roots with weak tips. Leaves are distorted with hooked tips and curled margins that often turn brown. Immobile in plants so symptoms of deficiencies show first in new growth.
Magnesium is vital to chlorophyll production and is important in most enzyme reactions. Magnesium deficiency causes different symptoms in different plants, but commonly includes leaf yellowing with brilliant tints. Leaves may suddenly drop off without withering. Symptoms show first on older leaves. Excess magnesium may cause calcium deficiency.
Manganese is a catalyst for many enzymes and is important for chlorophyll formation. Boron is necessary for the movement of sugars, for reproduction, and for water intake by cells. Zinc is necessary for the production of proteins and affects plant size and maturity. Copper is necessary for the production of proteins and is important for reproduction. Chlorine may affect carbohydrate metabolism and photosynthesis.
Ph Reaction in the Soil
70 60 59% 50 47% 40 30 20 19% 25% 22% 28% 10 0 After Planting Before/at Planting Fall Before/at Planting Spring
Fertilizer placement
Precision Agriculture GPS/satellite image of nutrient availability Areal photo overlaid with yield potential
Cultivation