Uso de extrato de nódulos como inoculante alternativo para fixação biológica de nitrogênio em feijão-caupi

Abstract

Cowpea has a high nutritional value and is a staple food on the table of small producers who, with the intention of maximizing production, come up against limitations, mainly financial, related to the acquisition of fertilizers and the application of new technologies such as inoculants. The study aimed to evaluate the efficiency of an alternative inoculant for biological nitrogen fixation in cowpea cultivars. The experiment was conducted in a greenhouse. A completely randomized experimental design was used in a 5 x 4 factorial arrangement, with four replications, with five cowpea genotypes: three commercial cultivars (BRS Aracê, BRS Tumucumaque and BRS Xiquexique) and two creole accessions (Pratinha and Verdinha); and four N sources: nodule extract inoculant, commercial inoculant, nitrogen fertilization 50 Kg ha-1 and control without N. Plant height, SPAD index, number of nodules and dry mass of shoot, root and nodule were evaluated . The treatment with inoculant based on extract of nodules was superior to the commercial inoculant in most of the items evaluated for the Pratinha cultivar, SPAD index and dry mass of nodules for the Aracê cultivar, shoot dry mass and number of nodules for the cultivar Blue greens and root dry mass for the Tumucumaque cultivar. BRS Xiquexique presented remarkable results when comparing the inoculant based on extract of nodules with the nitrogen fertilizer, presenting superior results when analyzing plant height, dry mass of shoots and nodules and number of nodules. It is concluded that the inoculant based on extract of nodules is capable of promoting the development of the studied cowpea genotypes