Efeito de sistemas de produção de milho silageme adubação nitrogenada na qualidade de latossolo do cerrado

Abstract

Corn silage is characterized by high demand and significant nitrogen removal, requiring substantial organic matter reserves and supplementation with fertilizers. At the same time, soil quality is becoming an increasingly important concern each year. With intensive agricultural exploitation worldwide and fertilizer use, especially in tropical countries, systems designed to preserve the chemical, physical, and biological attributes of soil have become an indispensable alternative for maintaining soil quality and environmental sustainability. This study evaluated the hypothesis that intercropping corn with brachiaria, combined with efficient nitrogen fertilizer use, can increase productivity and enhance the soil's physical and biological quality, promoting greater carbon incorporation in a Red-Yellow Latosol in the Cerrado region of Minas Gerais. The experiment compared monoculture corn silage with an intercropping system involving brachiaria under different nitrogen fertilization treatments. A randomized block design with split plots was used, covering treatments with three nitrogen sources: ammonium nitrate (CAN), urea + NBPT, and regular urea, in addition to a control and a no-nitrogen (NoNitro) treatment. Soil quality indicators, such as density, porosity, organic carbon content, and microbial activity, were evaluated, along with specific carbon fractions, including light organic matter fraction (LOM) carbon and total organic carbon (TOC). The results indicated that the corn-brachiaria intercropping system significantly improved soil structure by increasing porosity and basal respiration of soil microbiota compared to monoculture. Additionally, brachiaria was shown to increase soil organic matter and carbon sequestration, favoring sustainable management. However, for some variables, significant differences may require a longer study period to be fully observed. It was concluded that the corn-brachiaria intercropping system could mitigate soil degradation and improve its health in the long term in tropical regions. This study contributed to the development of sustainable agricultural practices, emphasizing the importance of strategic fertilization and crop management to maintain soil quality, increase carbon stocks, and enhance corn silage productivity.