Assessment of microbial respiration in sugarcane soil with different nitrogen's dosage

Microbial respiration is related to the amounts of microorganisms in the soil and is a measure of their quality. In a long-term sugarcane experiment, with six nitrogen levels (treatments), microbial respiration, agricultural yield and the interaction with climatic variables were determined. Factor analysis of variance and AMMI model were performed to describe the effect of nitrogen doses on microbial respiration. It was found that there are differences by phenological stages of the crop (4, 8 and 12 months after harvest), treatments and their interaction. There are increases in microbial respiration as the doses of N increase up to 150 kg /h of the fertilizer. The maximum microbial respiration value is obtained with an average N dose of 100.6 kg /h. There is a moderate relationship between microbial respiration with temperature and rainfall, but negative for the former and positive for the latter. The dynamics of microbial respiration and agricultural yield as a function of nitrogen doses present a similar response. The results indicate that the evaluation of sugarcane soil microorganism interactions can be useful to identify an optimal level of fertilization, as well as new sources of fertilizers.