Phosphorus and Potassium Tissue Testing in Corn and Soybean
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Iowa farmer and crop consultant interest in the use of tissue testing for phosphorus (P) and potassium (K) diagnostics in corn and soybean has increased in recent years. Some are using interpretations that were not derived from correlations of tissue test results with crop response or that were developed for other geographic regions. Iowa research since the 1950s has continuously investigated the relationships between crop yield response and soil test P and K with various test methods. That ongoing research has resulted in soil test interpretations that have been updated over time as needed and are reliable.
Mallarino, Antonio P. and Sawyer, John E., "Phosphorus and Potassium Tissue Testing in Corn and Soybean" (2018). Extension and Outreach Publications. 420.
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