Yield Responses to Different N-P-K Levels, and Correlations With Foliar Analysis, in Sand-Culture Studies With Corn, Sugarcane, and Cotton

Abstract

The layout for 28 concrete pits is described herein where sand-culture and irrigation studies under cover have been carried in Puerto Rico since 1940 with certain crops: Sugarcane, beans, corn, sweetpotatoes, and cotton. The data for 10 experiments performed with sweet corn, dent corn, sugarcane, and cotton are reported. These data included N-P-K contents of the respective leaves at different crop ages and yields obtained by varying the N or P or K levels from deficient to sufficient values, but keeping other major and minor nutrients constant. These experiments were important in showing that foliar contents of the major nutrients at specific crop ages can be used to predict or correlate with relative yield values. These correlations are not generally obtained with phosphorous and potassium in field experiments because the initial available phosphorus and potassium contents of the soil are usually high.