Different Soil Management Systems Promote Improvements in Nutrient Content and Litter Input

Agroforestry systems can benefit tropical soils by promoting greater diversity of plants and reducing or avoiding common practices used in conventional management systems, such as soil cleaning, plowing, and harrowing. In this context, we aimed to evaluate the supply of nutrients and litterfall in a dystrophic cohesive yellow Latosol (Oxisol) under the following management systems: conventional, artificial pasture, two agroforestry systems of different ages (7 and 12 years old), and an area of secondary forest. In the sampling areas, we collected composed soil samples from the 0-0.10, 0.10-0.20, and 0.20-0.40 m layers for the evaluation of chemical attributes and litterfall, and in the superficial layer for quantification of nitrogen, phosphorus, and potassium contents. Differences between management systems were measured using the principal component analysis. Litterfall supply was higher in the 12-year-old agroforestry system, followed by the 7-year-old agroforestry system, secondary forest, and conventional system, as well as the accumulations of nitrogen and phosphorus in the litterfall. Thus, replacing forests by crops promotes changes in the chemical attributes regardless of the use and management system. Although the conventional cultivation has improved some attributes, the soil quality has only been improved by agroforestry systems due to the greater supply of organic matter.