Economic analysis of rice and common bean production in succession to green manure crops and mecahnical soil decompression in Brazilian Savannah

ABSTRACT The previous cultivation of green manures and mechanical soil decompression are options to minimize compaction of the topsoil in no-tilage system (NTS) set in different production systems in the Brazilian Savannah. In addition, it is essential to relate these agricultural practices with the economic benefits generated through the production cycles. The objective of this study was to evaluate economically the effect of sporadic mechanical decompression of the soil and previous cultivation of green manure in the production and net gain margin of upland rice and "winter" common bean, under sprinkler irrigation, in NTS in lowland Brazilian savannah. This study was developed in the 2012/13 harvest and 2013 winter in Selvíria, state of Mato Grosso do Sul, in an clay texture Oxisol in the savanah in the state of Mato Grosso do Sul, in a randomized block design arranged in a 5 x 2 factorial arrangement with four replications. The treatments were a combination of five green manures (fallow (control), Cajanus cajan, Crotalaria juncea, Pennisetum glaucum and Urochloa ruziziensis) with and without mechanical soil scarification. The yields of upland rice and common bean grains were not influenced by the previous green manure cultivation; the upland rice grown in succession to Cajanus cajan in the presence of mechanical soil scarification provided greater increase in grain yield and higher gross margin profit. Beans cultivated in succession to Crotalaria juncea and Pennisetum glaucum in the presence of mechanical soil scarification, followed by rice cultivation, provided greater increases in grain yield and gross profit margins.