Sorghum Fertility Brian Arnall Oklahoma State University Dept Plant and Soil Sciences
Outline Nitrogen Phosphorous Potassium pH Micro’s
Soil Testing OSU, Ward, ect. $10 - $15 –20 lb N $9 –20 lb P $7.2 –¼ Ton Lime $5-10 »Per Acre!!!!! Some Co-Ops and Fertilizer Dealers, –Take and Process samples for FREE!!!!!!
Nitrogen Determined by Yield Level
Strips and Sensors
Independent of Yield Phosphorous
Independent of Yield Potassium
Variability
pH Issues Mixed Reports, some state more Al tolerant and others show less.
Nutrient Iron Manganese Copper Zinc Boron Chlorine Molybdenum Soil (lb/a)* 14,000 – 1,100, – 6, – 1, *Range of total in soils. From Chemical Equilibria in Soils. W.L.Lindsay, Wiley & Sons. Crop (lb/a )** **Calculated for 2 ton crop yield (67 bushel wheat). Micronutrients Needed by all Crops
Nutrients not found deficient in Oklahoma crops. Calcium. –Liming prevents Ca deficiency. Manganese. Copper. Molybdenum.
Nutrients seldom found deficient in Oklahoma crops. Magnesium. Sulfur. Iron. Zinc. Boron. Chlorine.
Mg Yellowing between veins, old leaves Dolomitic Lime Sul-po-Mag, K-Mag
Sulfur Can look like N, Yellowing between veins Gyp, S, Ammon Sulfate
Iron Yellowing between veins, new leaves Ferrous Sulfate, ect
Micro Nutrients Zinc, Bronze between Margin and Midrib. Bleaching on either side of Midrib Zinc Sulfate, Zinc Chloride, Zinc Chelate Boron, Borax Chloride, Upper Leave Wilt, Muriate of Potash which K is usually also deficient
Soil Testing Just Do It!
Thank You! Corn and Sorghum Nutrient Need Pete’s Sheets coming soon