Produção de matéria seca e marcha de absorção de nutrientes em Crotalaria juncea e Crotalaria spectabilis

Abstract

There are many benefits of crotalaria cultivation, including the high biomass production and N accumulation, nutrient cycling and antagonistic action on some nematodes, which have aroused the interest of the farmers. However, information about the nutritional requirement for these species remain scarce, so the purpose of this study was to determine the dry matter production and macronutrient uptake in Crotalaria juncea and Crotalaria spectabilis shoots. The experiment was carried out at Embrapa Agropecuária Oeste, in Dourados, Mato Grosso do Sul, from March to August 2017, in a randomized block design with two species of crotalaria (C. juncea and C. spectabilis) and thirteen collecting times for C. juncea, ten collecting times for C. spectabilis and three replicates. Samples were dried, weighed and, finally, submitted to laboratory analysis to determine the nutrient contents in each structure. The accumulation of nutrients in the shoots of the plants presented the order: K>N>Ca>Mg>P>S for both species, in which the stem was the main organ of nutrient accumulation. The nutrient exportation by the grains followed the order N>K>Ca>Mg>P>S for C. juncea and N>K> P>Ca>S>Mg for C. spectabilis. C. juncea accumulated higher amounts of nutrients and dry matter, and the time required for maximum accumulation was greater when compared to C. spectabilis.