AGRO-ECONOMIC INDICATORS FOR CARROT UNDER GREEN MANURE IN A SEMI-ARID ENVIRONMENT

ABSTRACT Green manuring is an important management strategy in tuberous vegetable production systems, since it improves the physical, chemical and biological properties of the soil and, consequently, increases in crop productivity and ecosystem balance. The objective of this work was to evaluate the agro-economic efficiency of carrot cultivation as a function of Calotropis procera biomass amounts incorporated into the soil during two growing seasons in a semiarid environment. The experiments were conducted in an experimental design of randomized complete blocks, with four treatments and five replications. The treatments consisted of four C. procera biomass amounts (20, 35, 50 and 65 t ha-1) incorporated into the soil. In each experiment, one plot with carrot without fertilization (control) was planted, for the purpose of comparison. The characteristics evaluated in the carrot were productivities of total and commercial roots, classified productivity of roots and production economic indicators. The maximum productivity of carrot roots of 35.90 t ha-1 was possible with the incorporation of 47.60 t ha-1 of C. procera biomass into the soil. The maximum net income of R$ 33.744,07 ha-1 in the cultivation of this vegetable it was achieved with the addition of the C. procera biomass amount to the soil of 42.81 t ha-1. The return rates obtained for the carrot cultivation in these optimized quantities were 1.53 and 1.28, respectively, of those achieved in the control treatment (without fertilization). RESUMO A adubação verde é uma importante estratégia de manejo em sistemas de produção de hortaliças tuberosas, pois melhora as propriedades físicas, químicas e biológicas do solo e, consequentemente, aumenta as produtividades das culturas e equilíbrio dos ecossistemas. O objetivo deste trabalho foi avaliar a eficiência agroeconômica do cultivo de cenoura em função de quantidades de biomassa de Calotropis procera incorporadas ao solo ao longo de duas estações de cultivos em ambiente semiárido. Os experimentos foram conduzidos em delineamento experimental de blocos ao acaso, com quatro tratamentos e cinco repetições. Os tratamentos consistiram de quatro quantidades de biomassa de C. procera (20, 35, 50 e 65 t ha-1) incorporadas ao solo. Em cada experimento, foi plantada uma parcela de cenoura sem adubação (controle), para fins de comparação. As características avaliadas na cenoura foram produtividades de raízes total e comercial, produtividade de raízes classificadas e i