Eficiência biológica, habilidade competitiva e rentabilidade do sistema de consorciação palma-sorgo

Abstract

The intercropping and irrigation practices are essential to the forage production temporal stability in the semiarid region where water resources and limited most often have high salinity levels. Moreover, the use of these practices depends on the adopted configuration crops and their economic analysis. Thus, it aimed to analyze the biological efficiency, competitive ability and economic profitability of the cactus-sorghum intercropping system. Cactus forage cv. Orelha de Elefante Mexicana (Opuntia stricta) and sorghum forage, cv. SF-15 were distributed in blocks, with four repetitions, in factorial arrangement 5 x 3, in which the plots were composed of four irrigation blades (25%; 50% 75% and 100%; based on reference evapotranspiration, ETo) plus the rainfed condition, and the subplots for three planting systems (cactus forage single, sorghum single and cactus forage-sorghum intercropping), with the planting proportions in the consortium of 92% of sorghum plants (170,000 plants ha-1) and 8% of the cactus forage (15,625 plants ha-1). The cactus forage was conducted during a year, comprising two cycles of sorghum (plant and ratoon). The crops yield was obtained at the time of the harvest. The biological efficiency of the intercropping was determined through the land use efficiency (LUE), land area equivalent in time (LAET), productivity index system (PIS) and land equivalent coefficient (LEC). Soon, the system ability was analyzed by competition ratio (CR), aggression (A) and yield actual loss or gains (YALG). Economic viability was calculated from the system's Total Operating cost (TOC) and of economic indicators as gross income (GI), net income (NI), monetary advantage (MA), gross margin (GM), benefit/cost ratio (B/R) and profitability index (PI). With the results, it was found that the individual or joint dry matter yield in the cactus forage single, sorghum single, intercropping cactus forage-sorgo, cactus forage of the intercropping and sorghum of the intercropping were 4,626.98; 14,073.19; 12,130.00; 3,572.79 and 8,557.22 kg ha-1, respectively. There was a reduction of the individual productivity of cactus forage and sorghum on the basis of the intercropping of 72% and 61%. The cactus forage-sorghum system provided 51% productive advantage (UET = 1.51), when compared to your monoculture. The A and PGAR indexes identified as sorghum crop dominated by cactus forage. According to economic analysis, the COT between irrigation blades treatments within the same production system varied little, depending only of the expenses with electric energy. However, when compared between rainfed and irrigated systems were checked values ranging from R$ 1,335.00 ha-1 the R$ 10255.33 ha-1. The cost of irrigation system and supplies accounted for 84% of the total costs. Sorghum systems and intercropping cactus forage-sorghum attained the highest values of RB (R$ 6,201.30 ha-1 and R$ 6,007.53 ha-1). However, the values of RL, VM, MB, B/C and IL presented negative values, indicating losses of the systems in the first year of cultivation. Thus, it was concluded: (i) irrigation blade from 50% of the ETo is the most recommended in sorghum single and cactus forage-sorghum intercropping systems; (ii) on the intercropping the sorghum has breaks in productivity higher than the cactus forage; and, (iii) based on simulated economic indicators for subsequent years, the adoption of irrigation events and cactus forage-sorghum intercropping system promoted profits from the second year of implementation.