Comportamento dos teores de carbono orgânico e nitrogênio total sob diferentes sistemas de manejo em latossolo amarelo

Abstract

Integrated soil management systems are becoming increasingly important as they increase the levels of carbon, nitrogen and other nutrients in the soil, favoring diversified production. Because these contents are the most sensitive indicators to soil-imposed changes, the objective was to evaluate the behavior of organic carbon (TOC) and total nitrogen (TN) in Yellow Latosol submitted to different soil management systems in the municipalities Mojuí dos Campos and Belterra, Pará. The evaluated systems were: native forest (NF), degraded pasture (DP), pasture crop-livestock integration system (PCLI), agricultural crop-livestock integration system (ACLI) and crop-livestock-forest integration system (CLFI). Soil samples were collected at depths of 0.00-0.05, 0.05-0.10 and 0.10-0.20 m during rainy, dry and rainy-dry and dry-rainy transitions. The increase in TOC and TN contents in ACLI during the rainy season shows the importance of plant residues resulting from annual crops through the mineralization of organic matter. While in the rainy-dry and dry-rainy transition periods, the systems that were rotated over the years, such as PCLI and ACLI, had a better behavior of their contents. Increasing temperature and decreasing rainfall during the dry season promoted higher accumulations of both C and N contents in the DP soil. However, despite the influence of seasonal periods, the ACLI system showed more significant behavior than the others, denoting the importance for soil conservation and improvement.