Efeitos de arranjos populacionais na produção de forragem de feijão guandu (Cajanus cajan (L) Millsp.) em região semi-árida.

Abstract

The objective of this study was to evaluate the forage production, the nutritional value, and the macronutrient contents in pigeon pea (Cajanus cajan (L.) Millsp.), cultivar Taipeiro. The experiment was carried out at the EMBRAPA Centro Nacional de Pesquisa de Algodão (CNPA), Patos, PB, Brazil, in plots with 40 m2 arranged in a randomised block design with three treatments (spacings: 1.0m x 0.5m; 1.0m x 1.0m and 1.0m x 2.0m) and five replications, on a CROMIC LUVISOIL Ortic planosoil vertic. The variables analyzed were: plant height, stem diameter, number of stems/plant, dry matter and fresh biomass production, crude protein, ash, organic matter, N, P, K, Ca, Mg and S contents. Data analyses showed that plant height, stem diameter and number of stems/plant were not affected by spacing. The highest N, P, K and S contents were observed in the 1.0 m x 2.0 m spacing, in the first cutting. In the second cutting, N, P, K, Ca e Mg levels showed a tendency of increase in the 1.0 m x 0.5 m spacing. Independently of the cutting order, S levels were higher when the plants were grown in the 1.0 m x 2.0 m spacing. The nutrients were extracted in the decreasing order: N > K > Ca > S > P > Mg and N > K > S > Ca > P > Mg in the first and second cuttings, respectively. Cutting pigeon pea 90 days after sowing produced the highest levels of crude protein (16.31%) and dry and fresh biomass (2.56 t ha-1 and 6.18 t ha-1, respectively).