Physical and economic yield of the black oat in Distrito Federal

Abstract

This work determined the best economical combination between irrigation and nitrogen levels, the marginal rate of substitution among inputs and to evaluate inputs effects on black oat (Avena strigosa Shreb) forage quality. Irrigation was done using a line source sprinkler system. It was used a randomized complete block design for the irrigation variable, with the factor nitrogen, a split plot on irrigation and five replications. The eight irrigation levels applied were: 1.3, 107.1, 135.7, 295.9, 330.3, 469.7, 544.3 and 546.1mm. The six nitrogen doses were: 0.00, 0.02, 0.04, 0.08, 0.16, and 0.32Mg/ha. The rude protein content for the maximum economical dry matter yield was 17.6%. Considering input costs and output prices of black oat forage, it was calculated the maximum economical yield of 3.87Mg/ha of dry matter for 280mm of irrigation depth and for 0.094Mg/ha nitrogen level, which allowed a profit of R$147.32 per ha. The marginal rate of substitution was found to be 0.44mm water per 1x10-3Mg/ha of nitrogen. Maximum dry matter yield 4.22Mg/ha was verified for the 336mm irrigation depth and for 0.22Mg/ha nitrogen dose. Mean neutral detergent fiber values obtained were lower than 55%.