GROWTH AND DEVELOPMENT OF COWPEA (Vigna unguiculata L.) LIMING WITH CALCITIC LIMESTONE IN THE MUNICIPALITY OF CAPANEMA, PARÁ

Abstract

Cowpea is one of the most important legumes in the diet of the population with lower purchasing power in the northern region, and limestone is one of the most used inputs for agricultural production. The objective of this study was to evaluate the performance of cowpea plants submitted to base saturation levels in the soil, using calcitic and dolomitic limestone as soil acidity correctives, and Ca and Mg suppliers in the soil.  The work was carried out in a greenhouse, at the Federal Rural University of the Amazon, Capanema Campus. The experimental design adopted was a completely randomized design, in a 5 x 2 factorial scheme, with five levels of base saturation (0%, 20%, 40%, 60% and 80%) and two types of limestone (calcitic and dolomitic), with 50 experimental units. The cultivar used in the work was BR3-Tracuateua. The following biometric and dry mass parameters were evaluated: plant height (ALT), stem diameter (DC), number of leaves (NF), leaf area (FA), root length (CR), number of pods (NV), leaf dry mass (MSF), pod dry mass (MSV), stem dry mass (MSC), shoot dry mass (MSPA), root dry mass (MSR) and total dry mass (MST). There was interaction between limestone sources and base saturation for MSV and MSR. It was found that cowpea responds positively to liming with calcitic and dolomitic limestone. It is recommended to adopt base saturation ranging between 60% and 80% to obtain better crop performances.