Comparing Measurements of the Effect of Residual Fertilizer Phosphorus in Some Iowa Soils1
- Charles M. Smith and
- John T. Pesek2
The accuracy of the chemical soil test (0.03N NH4F in 0.025N HCl) for predicting biological response to residual fertilizer P was determined for several Iowa soils. Significant correlations were obtained with various measurements in the field and greenhouse, including grain, total dry matter, yield of P and radioactively determined A values.
Soil test P was the most highly correlated with greenhouse A values and the relationship was essentially linear over the range of levels of residual P. One regression line described this relationship for all neutral and acid soils tested but was different from that for a calcareous (pH 8.0) soil. The soil test predicted the A values equally well regardless of whether the fertilizer P had been applied 1, 2, or 3 years previously.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © .