Diversidade bacteriana e emissão de N2O e CH4 em sistemas de integração lavoura-pecuária-floresta no bioma Amazônia

Abstract

The implementation of integrated farming systems have been increased among farmers. Besides, contributed to the conservation and carrying several other environmental services , such as reducing the emission of greenhouse gases. This research aimed to assess the total bacterial soil biodiversity and its relation to the emission of nitrous oxide (N2O) and methane (CH4) in integrated production systems in the Amazon.. The assessed treatments were: monoculture systems (crop (L), pasture (P) and eucalyptus forests (F), and integrated systems (pasture and crop (IPL), crop and pasture (ILP), crop with forest (ILF); pasture with forests (IPF); crop and pasture, both with forest (ILF-IPF), pasture and crop, both with forests (IPFILF) and crops, pasture and forest (IAFP)). In the rainy season most N2O emission was observed in the treatment T5 (ILP) with an average flow ug 42, 33 N m-2 h -1 , and lowest flow was observed in the T6 treatment (ILF) with an average flow of 5, 53 ug N m-2 h -1 . As for the dry period greater emission occurred in the T4 treatment (IPL) with an average flow of 4,17 ug N m-2 h -1 . In this period, in some treatments there was gas consumption, and the treatment was consumed most N2O T1 (F) with a consumption of -4, 14 ug N m-2 h -1 . As for CH4, the majority of the treatments worked with gas sink in both periods. In the rainy season the treatment T8 (IPF) was the most consumed gas, with the average flow -14,19 ug C m-2 h 1 , and dried T1 (F) treatment was more oxidized CH4, with an average flow -12,32 ug of C m-2 h1 . In the structure of bacterial communities of soil in the two assessed periods the management system adopted influenced bacterial groups. The observed bacterial communities grouped under the management adopted, formed only communities with integrated treatments and communities only with exclusive treatments. The pH and bacterial diversity (H ') were environmental variables that influenced the bacterial community structure. And yet, the CH4 gas showed greater association with environmental variables regarding N2O. With these results we can see that the seasonal and plant species variability may affect the emission of greenhouse gases (GHG), in the structuring and overall diversity of soil microorganisms, and the forestry component was shown to have potential to be used in systems for GHG mitigation