S?o Paulo State is the main sugar cane producer and these agricultural activities are carried out in predominantly sandy soils, which require large amounts of phosphate fertilizers and amendments. This work evaluated ...S?o Paulo State is the main sugar cane producer and these agricultural activities are carried out in predominantly sandy soils, which require large amounts of phosphate fertilizers and amendments. This work evaluated the fertilizer-effect on the Al, Ba, Fe, Mn and Ni released in a watershed with influence of sugar cane crops in the S?o Paulo State, Brazil, namely the Monjolo Grande Stream basin. Five surface water sampling campaigns were carried out at the mouth of Monjolo Grande Stream in February, April, June, September and November 2010, characterizing the following parameters: discharge, pH, temperature, electric conductivity, dissolved oxygen and total and dissolved concentrations of Al, Ba, Fe, Mn and Ni. Approximately 99% of Al and Fe are transported annually in association with suspended sediments carried to the Monjolo Grande Stream by sheet erosion. The results also demonstrated that the increasing Al, Ba, Fe and Mn concentrations dissolved in the waters of the Monjolo Grande Stream basin in the wet season are associated to phosphate fertilizers and amendments that are used extensively in agrichemical activities. However, with the current application rates, there has been no increase in the dissolved concentrations of these metals at levels that could pose risks to human health.展开更多
The regulation of water regime in the soil is the most important task in semi-humid climate with not even precipitation distribution conditions. Reduced or minimum tillage may change soil hydrological properties. The ...The regulation of water regime in the soil is the most important task in semi-humid climate with not even precipitation distribution conditions. Reduced or minimum tillage may change soil hydrological properties. The objectives of this study were to investigate the possibilities to manage soil water regime during the whole soil tillage system for sugar beet, which are especially sensitive for water deficit or abundance. Five field experiments were carried out at the Experimental Station of the Lithuanian University of Agriculture (Aleksandras Stulginskis University since 2011) (54°52'N, 23°49'E) during 1995-2010. The soil of the experiments was silty loam Luvisol. In this study we highlighted the reduction of primary soil tillage from deep annual soil ploughing to shallow ploughing, deep and shallow cultivation and no till, comparison of soil ploughing and subsoiling, presowing ploughed or unploughed soil tillage with different cultivators—S-tine, complex, rotary and others, soil compressing with Cambridge and spur rollers before and after sugar beet sowing investigations. According to the results of experiments, reduction of primary soil tillage conserved soil water. The highest storage of soil water in spring was observed in non-reversibly tilled or not tilled soil. Subsoiling led higher water infiltration rate, and top layer of subsoiled soil consisted less moisture content than ploughed. Sugar beet seedbed moisture mostly depended on soil tillage intensity and depth. Presowing rotary tilling was the top tillage method in the case of water preservation in ploughed or unploughed soil. Soil compressing with rollers mostly had negative or low influence on light loam Luvisol moisture content. Rolling with Cambridge roller effected on more rapid water transport from deeper to top sugar beet seedbed layers and higher evaporation rate.展开更多
文摘S?o Paulo State is the main sugar cane producer and these agricultural activities are carried out in predominantly sandy soils, which require large amounts of phosphate fertilizers and amendments. This work evaluated the fertilizer-effect on the Al, Ba, Fe, Mn and Ni released in a watershed with influence of sugar cane crops in the S?o Paulo State, Brazil, namely the Monjolo Grande Stream basin. Five surface water sampling campaigns were carried out at the mouth of Monjolo Grande Stream in February, April, June, September and November 2010, characterizing the following parameters: discharge, pH, temperature, electric conductivity, dissolved oxygen and total and dissolved concentrations of Al, Ba, Fe, Mn and Ni. Approximately 99% of Al and Fe are transported annually in association with suspended sediments carried to the Monjolo Grande Stream by sheet erosion. The results also demonstrated that the increasing Al, Ba, Fe and Mn concentrations dissolved in the waters of the Monjolo Grande Stream basin in the wet season are associated to phosphate fertilizers and amendments that are used extensively in agrichemical activities. However, with the current application rates, there has been no increase in the dissolved concentrations of these metals at levels that could pose risks to human health.
基金ob-tained through postdoctoral fellowship(No.004/38)funded by the European Union Structural Funds project“Postdoctoral Fellowship Implementation in Lithuania”.
文摘The regulation of water regime in the soil is the most important task in semi-humid climate with not even precipitation distribution conditions. Reduced or minimum tillage may change soil hydrological properties. The objectives of this study were to investigate the possibilities to manage soil water regime during the whole soil tillage system for sugar beet, which are especially sensitive for water deficit or abundance. Five field experiments were carried out at the Experimental Station of the Lithuanian University of Agriculture (Aleksandras Stulginskis University since 2011) (54°52'N, 23°49'E) during 1995-2010. The soil of the experiments was silty loam Luvisol. In this study we highlighted the reduction of primary soil tillage from deep annual soil ploughing to shallow ploughing, deep and shallow cultivation and no till, comparison of soil ploughing and subsoiling, presowing ploughed or unploughed soil tillage with different cultivators—S-tine, complex, rotary and others, soil compressing with Cambridge and spur rollers before and after sugar beet sowing investigations. According to the results of experiments, reduction of primary soil tillage conserved soil water. The highest storage of soil water in spring was observed in non-reversibly tilled or not tilled soil. Subsoiling led higher water infiltration rate, and top layer of subsoiled soil consisted less moisture content than ploughed. Sugar beet seedbed moisture mostly depended on soil tillage intensity and depth. Presowing rotary tilling was the top tillage method in the case of water preservation in ploughed or unploughed soil. Soil compressing with rollers mostly had negative or low influence on light loam Luvisol moisture content. Rolling with Cambridge roller effected on more rapid water transport from deeper to top sugar beet seedbed layers and higher evaporation rate.
