Recovery of Corn Yield on Gardena Subsoil as Related to Leaf and Soil Analysis
1974
Follett, R. F. | Grunes, D. L. | Reichman, G. A. | Carlson, C. W.
Our objective was to determine the relationship of leaf N and P and soil P (NaHCO₃-soluble) in exposed subsoils to forage yield restoration resulting from fertilizer treatment. Corn (Zea mays L.) was grown on a Gardena fine sandy loam. Fertilizer treatments consisted of NH₄NO₃, concentrated superphosphate, and manure. Half of the plots had 30 cm of topsoil removed (cut area), the rest had no topsoil removed (undisturbed area). Cut area treatments were evaluated against corresponding undisturbed area treatments as follows A coefficient of multiple determination (R²) of 0.82 resulted when the data was fitted to the following equation if leaf N was 2.9%, 90% yield recovery was obtained when leaf P was 0.27%. A leaf N level near 2.9% or more could be obtained by the addition of inorganic fertilizer N. However, high N and P rates or N and P plus manure were required to obtain 0.27% leaf P. Leaf P values from cut areas never equalled those obtained from the corresponding undisturbed area treatment. Leaf P on the cut area was closely related to soil P only if leaf N was also considered. These results indicate that a combination of plant and soil analysis is needed to identify fertilizer requirements. The potential for restoring subsoil yields was excellent and full recovery was accomplished the first year with a combination of N, P, and manure.
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