Carbon, Nitrogen, and Organic Matter of Soil in an Integrated Crop-Livestock System

Abstract

This study aimed to evaluate the effect of the integrated crop-livestock system on the contents and stocks of total organic carbon, total nitrogen, and soil organic matter. The experiment was carried out between April 2016 and February 2017, in a randomized block design in a strip-block scheme, with additional control treatment (fallow) and four repetitions. The treatments consisted of two densities of oat sowing (40 and 60 kg ha-1) in strips A and different grazing frequencies (without grazing - WG, one grazing - 1G, and two grazing - 2G) in strips B, besides fallow as a control treatment. The determinations of the contents of total organic carbon (TOC), total nitrogen (TN), and organic matter (SOM) were carried out in the soil layers of 0-5, 5-10, and 10-20 cm. Samplings were carried out after oat management, in the winter, and after soybean harvest, in the summer. The sowing density of black oats and the grazing frequencies were not able to promote changes in the total organic carbon and in the TOC stock, regardless of the time of evaluation. The use of 40 kg ha-1 of oat seeds would be recommended, as it does not promote changes in the increase in MOS, thus generating savings in the acquisition of seeds. The use of the lowest density of oat without grazing and one grazing promoted changes on the total nitrogen in the 5-10 cm layer after the removal of oats, when compared to the fallow, and it presented content similar to the management with two grazings.

Effects of different agricultural systems on organic matter and aggregation of a medium-textured soil in subtropical region

“…In the 0.20-0.40 m layer, the increase was 567%, corresponding to an average increase of 2.61 Mg ha -1 for each year after planting. These results, as well as those of the constituents, highlight the importance and influence of grasses, mainly through the action of their roots in deeper soil layers, which contribute to greater accumulation of organic matter and subsequent humification of this organic matter (Pires et al, 2022;Mattei et al, 2020;Oliveira et al, 2019). Subtropical climatic conditions also favor slower decomposition compared to tropical climatic conditions, which contributes to the humification process of SOM (Pellegrini et al, 2022;Leizeaga et al, 2022).…”