Green manure for the increase of soil carbon stocks in Typic Quartzipisamment of Cerrado

Abstract

The benefits gained with green manure are related to the sustainability of agricultural soils by the increase of organic matter in the production system, reducing the effects of acidity and improving other soil properties. The objective this research was to assess the potential of species used as green manures to increase the contents and stocks of total organic carbon (TOC), particulate organic carbon (POC), organic carbon associated to minerals (OCam) and carbon management index (CMI) in the soil. The experiment was conducted under field conditions, in a randomized blocks, five treatments (green manures Canavalia ensiformis, Cajanus cajan and Crotalaria juncea, fallow area and area of Cerrado native vegetation, without anthropic interference) and four replications. After flowering, the plants were cut, dried naturally, and then soil samples were collected at 0-10, 10-20 and 20-30 cm, for the granulometric fractionation of the organic matter. In the deepest layer the fallow area showed the highest stocks of POC and the native vegetation had the highest TOC levels. The green manure Cajanus cajan was efficient to increase the levels and stocks carbon in the soil, even in a short time.