Sistema silvipastoril em Neossolo Quartzarênico: relação solo-planta-atmosfera

Abstract

The removal of the original vegetation cover and the deployment of crops, combined with inadequate management practices, normally cause the deterioration of the physical quality and soil chemistry. On the other hand, the search for integrated crop alternatives associated with no-till system in crop rotation should be implemented in the Midwest and the structural and soil fertility changes become of paramount importance. Thus, the aim of this research was to evaluate the changes in the physical and chemical properties of a Quartzipsamment from different land use and soil management systems. Four agro-ecosystems were selected: Eucalyptus forest, extensive grazing, crop-livestock and crop-livestock-forest integration; and a preserved ecosystem: native vegetation of cerrado, located on the Model Farm II in Ribas do Rio Pardo, MS. Soil samples were collected at depths of 0-5, 5-10 and 10-20 cm in a completely randomized design with six plots of 150 m2 on each system. The crop-livestock and crop-livestock-forest integration systems provided the greatest contributions to improving soil fertility. There was antagonistic relationship between physical properties and soil chemical and sustainability evaluation, the most affected chemical attributes that physical. Microclimate and thermal comfort in a without shadow system (SS) and silvopastoral systems with eucalyptus geared towards east/west and north/south in summer and winter was also evaluated. The design was completely randomized in sub-scheme of split plots with five replications. The plots were planting directions on silvopastoral system (SSP/EW, SSP/NS) and a control treatment (SS). In subplots treatments were obtained collection times during the day (8, 11, 14 and 17 hours) and sub-subplots represented by distances from a swath of the trees (1, 4, 8, 12, 16, 20 m). The guidelines east/west and north/south differed for temperature, relative humidity, the black globe temperature and RTL during the winter. The results show the influence of shading on climate variations and thermal comfort indexes, making the harmonious environment and reducing the climatic differences between the stations. Indexes THI, BGHI and H showed the same sensitivity in distinguishing between environments and evaluated times, but in the summer, differentiation occurred during the hours from 14 to 17 hours and in winter the times of 8 to 14 hours.