Green house gas emissions as affected by soil management and acidity amelioration

Abstract

Liming is fundamental in soil remediation and to increase yield, but it results in increased greenhouse gas emissions, mainly CO2. There are indications that the use of silicate or lime plus gypsum could be effective in improving the balance of soil carbon compared to the sole use of lime. The objective of this work is to study the emissions of greenhouse gases,, and possible changes in carbon storage in the soil profile, as affected by soil acidity amelioration using silicate, lime and gypsum, under no tillage and conventional systems. The study will be carried out, soybean grown during the summer, followed by relay crops of corn + brachiaria, from 2012 to 2015, in Botucatu, São Paulo state, Brazil. The treatments are: control, lime, silicate, gypsum +lime and gypsum+silicate. The soil of both areas will be collected in depths of 0-10, 10-20, 20-40 e 40-60 cm, before treatment application and before soybean planting, to determine the fertility, carbon and organic matter fractionation. The straw on the soil will be evaluated periodically to determine dry matter and carbon contents. Foliar diagnoses will be done in all crops, and root mass, grain production and carbon content in the grains and roots, will be analyzed. The soil CO2, N2O and CH4 fluxes , will be determined after treatment application in 2012 and repeated in 2013 e 2014, after soybean planting and in March after brachiaria and corn planting. At the end of the experiment the carbon balance in the system will be determined.