Crop Response to Soil Acidity Factors in Ultisols and Oxisols in Puerto Rico X1. Cassava

Abstract

Cassava (Manihot esculenta Crantz), one of the major sources of carbohydrates throughout the tropics, was found to be very tolerant to high soil acidity in two Ultisols and one Oxisol. About 85% of maximum yields were obtained when Al saturation of the effective cation exchange capacity of the soil was around 60%, but highest yields were attained at about pH 5.3 with no exchangeable Al. Soil acidity factors did not affect the chemical composition of the cassava leaves, except for Mn, which increased with decreasing pH of the Oxisol. Tolerance of cassava to soil acidity was also confirmed by the fact that yields of 12 commercial varieties were not affected by Al saturation levels varying from 0 to 60% in an Ultisol.