Propriedades físicas de um latossolo após calagem, gessagem em manejo do solo

Abstract

The tillage system, widely used in Rio Grande do Sul, provides improvements in plant soil environment. However, due to the traffic of machines in areas not have upturn the formation of subsurface layers with higher compaction states. To adapt the soil to crops is necessary practices of tillage. The implements used for these practices beyond breaking compacted layers end up breaking the soil aggregates, disrupting it. In lime and gypsum is added to the soil ions that can influence the approximation of soil particles and consequently the aggregation of this. The objective of this study is to evaluate the effects of liming and gypsum application practices in the area of tillage subjected to soil management operations, the physical properties. In June 2009 the establishment of the experiment was conducted, in Oxisol cultivated over ten years under no-tillage, was adopted split-split plot design, with different tillage operations of the allocated land in main plots (tillage + plowing, tillage + scarification and continuous tillage), lime rates in subplots (0, 2, 4 e 6 Mg ha-1) and rates of gypsum in subsubplots (0, 2, 4 e 6 Mg ha-1). Three years after the implementation of the trial trenches soil samples were collected and opened. Samples were collected at different layers (0 a 5, 5 a 10, 10 a 15, 15 a 20, 20 a 30 e 30 a 40 cm) in order to diagnose the effect of product in the soil profile. Soil core soil samples were collected to determine soil density, microporosity and macroporosity and total porosity of soil penetration resistance. Blocks with preserved structure were collected and manually defragmented in aggregate. With the aid of sieves were separated aggregates with diameters between 8 a 4,75 mm for analysis of aggregate stability in water and aggregates with diameters between 1 e 2 mm for laser diffraction analysis of microaggregates. Liming and gypsum altered the physical properties, without a decrease in macroporosity and total porosity, increased resistance to penetration, which decreased the area under the scarification. The aggregation of the soil was influenced by management practices and lime and gypsum. Smaller fractions of aggregates are more sensitive in diagnosing changes in soil structure, broken down by the Stability Aggregate Index for laser diffraction.