Role of cropping systems and soil acidity on soil quality and crop yield in long-term agriculture

Abstract

Agricultural production systems based on monoculture or crop sequences with few species can lead to soil depletion and reduced microbial biodiversity. On the other hand, more complex systems tend to improve the biological properties of the soil, with a potential impact on sustainable production. Correction of acidity is a necessary practice in Brazilian acid soils and contributes to increased agricultural productivity and affects several soil attributes. The combined effect of acidity correction and complex rotation systems on agricultural productivity and soil quality are better evaluated in long-term studies in which the effects of management practices are consolidated and less affected by short-term climate fluctuations. The advances in the studies of soil microbiome made it possible to evaluate microbial activity as indicators of soil quality, greatly affected by management practices. Long-term studies with integrated data analysis, such as those in this project, are relatively rare. Therefore, we hypothesize that the joint analysis of data on physical, chemical and biological soil properties can allow the choice of crop rotation systems that combine soil health and high crop yields, as well as in the beneficial interactions between soil, plant and microorganism in the system as a whole. To verify this hypothesis, soil data survey and microbiological analyzes will be carried out in a long-term experiment conducted since 2006 at the Experimental Farm of the Faculty of Agronomic Sciences/UNESP, in Botucatu-SP. Integrated data evaluations include a) employment of quantitative real-time PCR (qPCR) techniques of the nitrogen (N) cycle processes; b) enzymatic parameters of the carbon (C), phosphorus (P) and sulfur (S) cycle ) for nutrient cycling determinations; c) sequencing of the 16S rRNA gene and the ITS region ("Intergenic Transcribe Space") in samples collected at the beginning and after 15 years of crop rotations, for the determination of bacterial and fungal communities; d) survey of data on accumulation of plant residues and crop productivity, e) chemical and physical properties of soil in production systems for modeling data from agricultural systems. From the integration of data on chemical, physical, and biological soil properties in production systems combined with soil acidity correction, it is expected to improve the understanding of the potential of grain production in tropical soils associated with soil quality. (AU)