Crop Response to Soil Acidity Factors in Ultisols and Oxisols in Puerto Rico-Soybeans

Abstract

The effect of various soil acidity factors on yield and foliar composition of soybean (Glycine max (L) Merrill) were determined in three Ultisols and one Oxisol. Soybeans responded strongly in yield and foliar composition to variations in soil acidity of the Ultisols and to a lesser extent to variation in acidity of the Oxisol. The best correlations were obtained with the Corozal soil (Ultisol) where the yields were increased from 62 kg/ha, when the Al saturation was over 60%, to about 2,000 kg/ha, when the Al saturation was less than 10% (pH 5.6). The least response was obtained with the Coto soil (Oxisol, irrigated). The highest yield of 3,555 kg/ha was obtained when the Al saturation was less than 10%. About 71% of the maximum yield was obtained at over 30% Al saturation (pH 4.3). Variation in the acidity factors significantly affected the N and Ca content of the soybean leaves on the Ultisols, whereas the other nutrients were unaffected. In the Oxisol, only the Mn content was affected. Nodulation in the Ultisols was severely reduced as the percent Al saturation increased.