Ambiente semiárido estoques de carbono orgânico e nitrogênio sob sistema silvipastoril e o manejo de solo tradicional

Abstract

An adequate amount of soil organic matter is considered essential for long-term sustainable agriculture. Very low values generally decrease crop productivity. Soils in semi-arid regions are marked by low productivity potential, coupled with low levels of nutrients, low drainage and low concentration of organic matter. Carbon in the soil plays an essential role in soil quality, availability of nutrients for plants and environmental functions. Nitrogen stocks increase crop productivity and improve soil physical, chemical and biological properties, contributing to the sustainability of the agro-ecosystem, minimizing impacts on the environment, supplying mineral fertilizer and mitigating global warming, making nutrients available for the plants. The present study quantified the stocks of carbon and nitrogen in two areas located in a semi-arid region, in a Silviculture + Pasture (Silvipastoril) System and in a Pasture System, in the region of the Hydrographic Basin of the Pajeú River, Sertão of the state of Pernambuco - Brazil, with a comparison area of preserved Caatinga. Analyzes of the physical, chemical and biological qualities of the systems were carried out. Were opened 8 trenches per treatment, and deformed and undisturbed soil samples were collected from depths 0 - 10, 20 - 30 and 50 - 60 cm, for physical, chemical and microbial analysis, following the EMBRAPA protocol (2017). The soils of the Silvipastoril and Pasture Systems were classified as Neossolo Flúvico, and that of the Caatinga as Cambisolo Háplico, both with a sandy loam texture. The values obtained were submitted to varianic analysis, with the averages being tested at 5% by the Tukey test. In general, the Silvipastoril System presented better results in carbon and nitrogen stocks, in the initial layers of soil, possibly influenced by the dynamics of the litter from the trees.