Minnesota/Kentucky fertility based on ENERGY | The real world work we have done will show that, less sulfate of Potash will have a greater impact on K then KCL this would be due to the information below and will as the measurement of millhouse units which is a chemistry measurement and SOP run at 98,780 unit and KCL runs at 19,780 units.
If we are going to take chemistry and the interaction of nutrients I believe that you will find over time that you can raise high yielding crop with less than 300 lbs. SOP considering we could lose more than 50% of KCL which would equate to 75 lbs. of actual K and with the math this would be 150 lbs. per acre SOP which is a 1-1 ratio KCL to SOP and I would run less we have one farm with 20 years of no K applied and yield are increasing we have started using 200 lbs. of 17-9-7-5s-7ca which is a blend of ammonium nitrate and AMS.
Why Potassium Sulfate?
The importance of Sulfur for vegetable yield and quality is well documented in the literature. Both are contributing factors for improved product marketability and profitability. The sulfate source of K is often preferred where crops are sensitive to Cl, where salinity problems exist, or when very high quantities of K are required (Stewart, 1985 and Zehler et al., 1981).
Under different levels of rainfall, leaching was measured when K was applied from various sources (Sartain, 1988). Less K was leached from the sod root zone when K was applied as SOP rather than MOP (Table 27).
Table 27. The influence of source on leaching loss of K.
“Rainfall” applied, inches K Source
10 20 50 75 100
% K Lost
Potassium chloride, KCI 17 75 91 91 94
Potassium sulfate, K2SO4 0 15 53 79 79
Potassium phosphate, K3PO4 0 0 0 18 33
Sartain, 1988.
Summary
Plant requirements for K and S supplied in SOP have been summarized for a number of crops around the world. Specific crop requirements and sensitivities emphasize the role of SOP in building sound soil fertility programs. Recognition of the increasing needs for supplemental S in crop production, combined with the established roles of K and S in plant physiology makes SOP a component of choice in balanced plant nutrition.
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fertilizing soybeans
