Agro-economic efficiency indicators in lettuce bi-cropping in intercropping with beet as a function of green manure and population densities in semi-arid environment

Resumo

In the search for a intercropping system that provides high productivity per unit area, greater diversification of production, high quality products and mainly agro-economic return, this work aimed to assess whether there is agro-economic viability of the lettuce bi-cropping in intercrop with beet, under several equitable amounts of M. aegyptia and C. procera biomass (20, 35, 50 and 65 t ha^-1 on dry basis) in different population densities of lettuce (150, 200, 250 and 300 thousand plants of ha^-1 lettuce), combined with 500 thousand plants per hectare of beet in two years of cultivation in semi-arid environment. The commercial productivity of beet and the productivity of lettuce leaves were evaluated, as well as the agronomic indices: land equivalent ratio (LER), area-time equivalent ratio (ATER), productive efficiency index (PEI), score of the canonical variable (Z), actual yield loss (AYL), and the economic indicators: gross income (GI), net income (NI), monetary advantage (MA) and rate of return (RR). The highest agro-economic returns of the beet-lettuce intercropping were achieved with LER and ATER of 2.59 and 1.39; PEI and Z of 0.97 and 2.32; and AYL of 10.66; and RB, RL and VM of 94,742.89; 59,121.45; 56,631.98 R$ ha^-1 and TR of R$ 2.75 for each real invested, respectively, in the combination of 65 t ha^-1 of M. aegyptia and C. procera biomass and lettuce population density 300 thousand plants per hectare. Beet was the dominant crop and lettuce the dominated one. The beet and lettuce intercropping is highly viable when properly manured with biomass mixtures of M. aegyptia and C. procera, as they express agronomic and economic viability and sustainability in semi-arid environment.