Biological nitrogen and protein production of Leucaena spp. Lines growth for forage in protein banks

Abstract

Leucaena spp, can be a valuable legume component of tropical forage systems since they have the capacity to produce up to 3 to 4 of protein/ha/year. Thus, we have been testing various Leucaena lines at Campo Grande, MS for potential in providing supplemental protein in beef-cattle production systems in Central Brazil. L. cunningham, L. pulverulenta, L. divenifolia, L. campina grande and L. Ieucocephala Peru type were evaluated in 12 x 22 m plots arranged in a randomized block design; plant spacing was 3 m between rows and 1 m between plants in the row. Cuttings to a 30 cm hight were made in September, 1982 and January, 1983. Subsequently, green matter (including the edible fraction, e.i. leaflets, pods and stems less than 1 cm in diameter and the stem fraction not useful as forage),dry matter (DM) and nitrogen (N) were measured. We had difficulty in establishing L. diversifolia, hence it was eliminated from the trial. Moreover, L. pulverulenta had to be replanted and thus yielded insufficiently to be cut. L. campina grande, L. cunningham and L. leucocephala produced 6.8; 9.9; and 10.1 t DM/ha in the edible fraction accumulated from the two cuttings. Nitrogen accumulated in the aerial biomase was 267, 370 and 376 kg/ha/year respectively, for the three acessions. Considering that a Brachiaria decumbens pasture, our major grass forage, maintains a yearly nitrogen offer, in the available forage of 100 to 250 kg CP/ha, the addition of 2,000 kg of CP obtained in the Leucaena protein-bank represents a valuable tool for supplementing cattle diets in Central Brazil.