Produção, acúmulo e decomposição de fitomassa em sistemas de produção de soja sob plantio direto

Abstract

The pursuit of soy production to improve soybean productivity. This research aimed to evaluate the flow of phytomass production and decomposition in the flowering and senescence of grain crops and cover during the off season, and its effects on soybean crop productivity in succession. The experiment was conducted during the agricultural year of 2016/17, being the third year of conduction, in the Experimental Station of the Federal University of Rondonópolis - UFR in Dystrophic Red Latosol, implanted in a randomized block design, with nine treatments and four repetitions being S1 : Pousio PD; S2: Fallowing PC; S3: C. spectabilis; S4: Corn + C. spectabilis; S5: P. glaucum; S6: U. ruziziensis; S7: Sunflower + U. ruziziensis; S8: V. unguiculata; S9: Corn + U. ruziziensis. The results related to the aerial part of the cover crops and the soybean were submitted to analysis of variance and, when significant, in the qualitative data the Scott-Knott test was used at 5% of probability using the software SISVAR (FERREIRA, 2008). The quantitative data were adjusted in equations using the SIGMA PLOT 10.0 software. The production systems had significant effects for all the variables analyzed in the second harvest of the agricultural year of 2016/17. The maize + C. spectabilis and maize + U. ruziziensis consortia present a longer half-life and, consequently, a lower rate of decomposition. The production systems that presented increase in the yield of soybean were C. spectabilis, Milho + C. spectabilis and Girassol + U. ruziziensis. The treatment V. unguiculata presented smaller accumulations of phytomass, so it does not explain the higher yield of soybean. Maize + C. spectabilis presented higher phytomass inputs in flowering and senescence, lower rate of decomposition and resulted in higher soybean yield, so it was highlighted in all evaluated variables.