Soil quality for sustainable agricultural production

Abstract

Soil quality can be defined as the ability of a soil to produce food and other products, and to perform various environmental functions. Soil structure, and in particular soil aggregation, is determinant in the role of soils as an environmental buffer and it is the single-most important factor influenced by management in controlling soil erosion and diffuse pollution. Researchers have been demonstrated that increasing soil organic matter (SOM) it is possible to increase crop yield by enhancing soil structure, having as consequence increase available water and air capacity; enhance cation exchange capacity (CEC), improve biotic activity of micro-organisms and improve the supply of nutrients. Enhancing soil structure makes soils less prone to compaction and soil erosion. Tillage is the principal agent producing soil disturbance and subsequent soil structure modification, increasing potential SOM loss by erosion and biological decomposition. Conventional tillage with intensive soil disturbance promotes rapid decrease of SOM and subsequent CO2 emission increase. A chemical, physical and biological soil degradation process then develops, negatively affecting crop productivity. However, tillage systems that increase SOM enhance soil structure, as well as atmospheric C sequestration. However, the increases also depend on other factors such as soil texture and mineralogy and climate. In tropical and subtropical areas, where high temperatures and humidity accentuate SOM degradation, a main agricultural research goal should be the development of management systems that increase and/or maintain the SOM. Therefore, knowledge of the main factors involved in SOM increase is fundamental for establishments of better soil management systems for agricultural production. Our research group in Brazil (from UNESP) are currently actively studying aspects of soil management system for sustainable crop production. In 2008 we have an opportunity to catalyze this research effort through international collaboration. Discussions since 2008 with Dr. Denis Angers, Senior Research Scientist from the Soils and Crops Research Centre/Agriculture and Agri-Food Canada, about ongoing soil management system projects and possible new research interventions have encouraged our research group to send a Ph.D. student (Marcio dos Reis Martins) to spend a whole year in Canada, developing part of his work, under Dr. Angers co-adviser. During this period, we have verified the needs of Dr. Angers knows our tropical system in order to participate more effectively on the discussions of the results obtained by Marcio so far, as well as, to get knowledge for further studies on tropical soil management system, which have led to the present proposal. The goal of this visit will be: 1) work collaborative to analyze more comprehensively data set already obtained by the Ph.D. student (Marcio) in Canada, under Dr. Angers co-adviser; 2) to define the next part of Marcio's dissertation for the degree of Ph.D., which will be developed in Canada; 3) to contribute to new research activities; and 4) to jointly propose further studies on the efficient use and management of soil for sustainable agricultural production. During the visit, Dr. Angers will work closely with graduate students on their research projects on soil management, present seminars about his ongoing researches to people from UNESP Campus of Jaboticabal and Botucatu, as well as from ESALQ/USP, aiming to show his work in order to stimulate students and researches to jointly propose further collaborative studies (AU)