Microbiological attributes of a cultivated Plinthosol with sugarcane on different levels of straw

Abstract

The objective of this work was to evaluate the microbiological attributes of a Plinthossol cropped with sugar cane in straw. The experiment was installed in União (04 ° 51’09”S and 42 ° 53’10 ‘’ W, altitude 52 m), northern region of Piauí state, Brazil. The experimental design was randomized blocks, with four replications, and treatments corresponding to different rates of straw (Mg.ha-1) (0, 4.19, 9.54, 13.04 and 18.38). Microbiological attributes were determined at a depth of 0-10 cm. Data was submitted to analysis of variance, cluster analysis and main components. An increase of straw in the soil influenced the stocks and contents of C, Cmic, Nmic, respiration and microbial and metabolic quotients. Cluster analysis combined the treatments into three distinct groups. 9.54 Mg.ha-1 of straw treatment was isolated from other treatments, being strongly correlated to the microbial quotient. The group formed by the treatments 13.04 and 18.38 Mg.ha-1 of straw correlated with most of the evaluated attributes, being the best proportions to be used to improve soil quality.