Atributos físicos do solo em função do manejo e sucessão de culturas em ambiente amazônico

Abstract

This study aimed to evaluate the physical attributes in different systems of soil management, cultivated with soybean and corn in the summer in succession to corn or beans in the region zone the mata of Rondonia. The study was conducted considering two consecutive experiments for two seasons, 2011/2012 and 2012/2013, the Universidade Federal de Rondonia, in Rolim de Moura, RO. The soil was classified as Oxisol Haplustox. Every season, the experiments were conducted in a randomized block design, with a split plot scheme, with three replications. In the plots of soil management systems were allocated, being the season 2011/12: PC (conventional tillage); PC+S (conventional tillage with subsoiling operation); PD (no tillage); and PD+S (no tillage with subsoiling operation in the fourth year, coinciding with the year of the experiment); and season 2012/13: PC (conventional tillage), PC+S (conventional tillage with subsoiling operation), PD (no tillage) and PD+SA (no tillage with subsoiling conducted in 2011). The subplots were composed of the same succession of crop in two seasons: SF (soybean/beans); SM (corn/soybean); MF (corn/beans); and MM (corn/com). Soil samples were performed at the depths from 0.0 to 0.05 and 0.05 to 0.10 m, being determined the physical attributes: soil bulk density, soil macro and microporosity, total soil porosity and aggregate of stability. No need for soil mobilization, even occasionally, with the subsoiler no tillage system. This no tillage had higher aggregate stability, independently of the succession of crop used. The soil tillage systems have favorable physical conditions after soil mobilization, however, quickly return the restrictive conditions for plant growth. Conventional soil management systems are more dependent on of the plant species in crop successions for improving the soil physical attributes. The succession of crops favored soil management systems.