Physical and chemical modifications and organic matter fractionation as affected by crop system and superficial liming and silicate application

Abstract

In no tillage system, soil mobilization is restricted to sowing furrows. Plant residues and fertilizers accumulate on soil surface, accelerating acidification. In Brazilian soils, this process is continuous and accentuated, resulting in low nutrient avaliability and high H+Al levels. Therefore, either in conventional or no tillage system, input application is necessary, mainly, materials for acidity correction. The present research has as objective to evaluate the influence of different crop systems in no tillage and superfical application of material for acidity correction on soil physical characteristics, base mobility, soil acidity correction, organic matter fractions, as well as nutrition and yield of grain crops in dry winter region. This work will be developed in the growing seasons of 2008/2009, 2009/2010 and 2010/2011 as a continuation of an experiment that began in the growing season of 2006/2007, on Lageado Experimental Farm, College of Agricultural Sciences - UNESP, Botucatu-SP-Brazil. Summer crops will be sown in October of 2008, 2009 and 2010. Fall/winter crops will be sown in February of the subsequent years. The experimental design was the completely randomized block, with subdivided plots and 8 replications. Main plots consisted of four crop systems (I. "Season/Forage"; II. "Season/Relay crop"; III. "Season/Fallow"; IV. "Season/Green manure/Cover crop"). Subplots consisted of two sources of material for acidity correction and a control (I - Dolomitic lime; II - Calcium and magnesium silicate - Agrosilício®; III - No correction). The following evaluations will be carried out: dry matter production and macronutrient level for all crops, yield components for grain crops, soil chemical attributes (36 and 48 months after acidity correction - October of 2006), soil physical attributes, organic matter fractionation and residual lime analysis after the second harvest of fall/winter crops (48 months after acidity correction) and production costs. (AU)