Forage sorghum in succession to green manures in the region of Mossoró, RN

Abstract

Forage sorghum behavior in succession to green manures was studied in the region of Mossoró, RN, Brazil. The experiment was carried out in a complete randomized block design with three replications. Treatments tested were seven legume species (Mucuna aterrima, Canavalia ensiformis, Cajanus cajan, Dolichos lab-lab, Crotalaria juncea, Crotalaria spectabilis, and Vigna unguiculata) and a mixture of the legumes plus corn, sorghum and sunflower, and spontaneous vegetation as a control. Forage sorghum cultivars BR 601 and IPA 467 were sowed after soil incorporation of green manures. Determinations included dry mass of green manure shoot and of sorghum leaves, and also contents of N, P, K, Na, Ca and Mg from green manure shoot and sorghum  leaves. In relation to the control, all green manures improved dry mass of forage sorghum, and the best performance was provided by Mucuna aterrima. Mixture of green manure species did not show advantage in relation to isolated species. In this experiment it was not possible to determine the influence of green manures on soil fertility or sorghum nutrition.