Frações da matéria orgânica do solo em função de culturas, sob sucessão e rotação

Abstract

The no-tillage system has been adopted by most grain producers in the Cerrado region, because when properly managed, it can increase soil organic matter contents. The objective of this work was to evaluate the contribution of total organic carbon (TOC) and particulate organic carbon (TOC) as a function of cover crops used in no - tillage system. The experiment was carried out at the Fazenda Experimental de Ciências (FAECA) of the Universidade Federal da Grande Dourados, located in the municipality of Dourados - MS, being implanted in the 2014/2015 crop in a soil classified as a Distroferric Red Latosol. The treatments consisted of: fallow/soybean, corn/soybean, corn + Brachiaria/soybean, oats/soybean, wheat/soybean, crambe/soybean, niger/soybean And the samples collected in the layers of 0-5, 5-10, 10- 20 and 20-40 cm. The total organic carbon was quantified and particle size fractionation of the particulate organic carbon was performed. The area in which Niger was planted had the highest TOC levels in the 0-5 and 5-10 cm layers, the Niger highlight in relation to other crops was probably associated with its high phytomass contribution, whereas for the POPs The treatments with grasses obtained better results in the agricultural year of 2014/2015, the particulate fraction being the most labile of organic matter is considered as an efficient indicator of the management adopted in the soil, we can verify that the layers of 0-5 cm and 5 -10 cm in all crops had a good performance in relation to the POC, so the choice of which coverage would be ideal would depend on which is easier to obtain, cost optimal benefit among other factors that would affect decision making. These results are mainly due to non-tillage, an essential factor for the accumulation of carbon, the improvement of fertility by fertilization, liming and contribution of corn phytomass over the years in succession with soybean and rotation with crops of autumn winter in the experimental area.