Estoques de carbono e nitrogênio no solo em sistemas agroflorestais e em sistemas de pastagem em monocultivo

Abstract

Agriculture and livestock farming, historically essential for human development, face challenges due to rapid population growth and high food demand. Additionally, increasing concerns about global temperature rise from accelerated greenhouse gas emissions further drive the need for the development of sustainable production systems. In Brazil, both activities significantly contribute to socioeconomic progress, but the challenge is how to maintain productivity without drastically harming ecosystems and their natural resources. Innovative practices in regenerative livestock farming and agroforestry systems offer solutions to prevent the degradation of conventional pastures and promote environmental sustainability. This study aims to characterize an agroforestry system focused on dairy farming on a property in the Brazilian Cerrado and evaluate soil carbon and nitrogen stocks in three different agroforestry treatments: Mombaça component, agricultural component, and arboreal component, comparing them with carbon (C) and nitrogen (N) stocks in degraded pasture and managed pasture, both of which are monoculture systems. Soil samples were collected using a Dutch auger at six depths (0-10; 10-20; 20-30; 30-40; 40-50; 50-100 cm), with three random simple samples taken at each treatment. Composited samples for each depth were analyzed at the Soil, Plant Tissue, and Fertilizer Analysis Laboratory and the Atomic Absorption Spectrometry Laboratory, both at the Federal University of Viçosa (UFV) – Department of Soils. Results revealed that carbon (C) and nitrogen (N) stocks in the soil were significantly higher in the surface layers of managed pasture as a monoculture. In the deeper layers, the difference in C and N stocks between treatments was less pronounced, suggesting that the management system has a stronger influence on the soil surface layers, especially between 0 and 20 cm depth, over a period of 2 to 3 years. Long-term studies extending beyond 20 years are necessary to assess the impact of the management system on deeper soil layers.