Manejo nutricional em pau de balsa, estoque de carbono no solo e intervalo hídrico ótimo

Abstract

Degraded pastures reduce profitability, contribute to the increase in silting up of rivers, in addition to reducing the infiltration and storage of water in the soil, and also favor emissions of greenhouse gases. Planted forests are a viable option for reversing the process in the soil: new fast-growing forest species, such as the balsa wood (Ochroma pyramidale), are indicated as a good economic alternative and with environmental gains, by the sequestration of atmospheric carbon and for the physical recovery of degraded soil. Fertilized increases in biomass production balsa wood, anticipating the shallow cut. However, there is little research that integrates aspects of nutritional management, carbon stock in the soil and least limiting water range (LLWR). The objective of this work was to evaluate how nutritional management, with increased fertilization, alters the carbon stock in the soil and whether the physical-hydro quality of the soil improves, based on the LLWR after seven years of planting. The experiment was implemented in 2011 at the Federal Institute of Education, Science and Technology of Mato Grosso (IFMT) Guarantã do Norte Advanced Campus. The carbon stock in the soil was evaluated at the initial fertilization levels, in a randomized block design with three replications for the 0-0.30 m layer, in a Yellow Red Latosol. Additionally, it was also contracted with soil data from before the experiment was implemented, in addition to an area of native forest and degraded pasture. In undisturbed samples, in the 0-0.10 m and 0.10-0.20 m layers, it was evaluated if the physical-hydric quality improved, having the LLWR as a base and compared with the degraded pasture, after seven years of planting. It is concluded, after seven years, the proper fertilization of the balsa wood increases the carbon stock in the soil in the 0-0.30 m layer by 18%. Still, it was observed that the nutritional management of the balsa wood, with increased fertilizer dose, promotes improvement in the physical-hydric quality of the soil, restricted to the planting line.