Lima beans production and economic revenue as function of organic and mineral fertilization

摘要

Lima beans (Phaseolus lunatus L.) are alternative food and income sources for the population of Northeastern Brazil. In this region, lima beans are consumed either as green or dry grains. However, low yields have been observed, a challenge that could be overcome by adequate organic and mineral fertilization. This work intended to assess lima beans yield, cultivar Raio de Sol, as affected by doses of cattle manure in the presence and absence of mineral NPK fertilization. The experiment was carried out at the Federal University of Paraíba, Brazil, from September, 2004 to May, 2005. The experimental design was of randomized blocks, with four replications, 40-plant plots, spaces of 1.00 x 0.50 between and within rows, respectively. Treatments were displayed in a 6 x 2 factorial, corresponding to manure doses (0, 10, 20, 30, 40 and 50 t ha-1) and presence and absence of NPK. Green and dry grain, and pod yields were analysed, as well as the economic revenue for pods and dry grains. To measure the economic efficiency, pods and dry grains were employed as the exchange units. Maximum pod yields (12.6 and 11.2 t ha-1) were achieved with 21.4 and 23 t ha-1 of manure, with and without NPK, respectively. Highest green grain yields (11.1 and 9.9 t ha-1) were obtained with 21.3 and 22.9 t ha-1 of manure, with and without NPK, respectively. The highest yield of dry grains (3.5 t ha-1) was obtained with 26.6 t ha-1 of manure combined with NPK. In the absence of NPK, the use of cattle manure resulted in an average dry grain yield of 2.0 t ha-1. The maximum economic efficiency for pod production was reached with 17 and 18.6 t ha-1 of manure, with predicted net incomes of 2.88 and 3.36 t ha-1 of pods, in the presence and absence of NPK, respectively. For dry grains, the maximum economic efficiency was achieved with 23 t ha-1 of manure, in the presence of NPK, which produced a net revenue of 2.12 t ha-1 of dry grains.