Stocks of elements in roots in areas of post-pebble mining recovery in the Pará state

Abstract

Mining in the municipality of Capitão Poço, Pará, has resulted in soil degradation as the main consequence. Therefore, this study aimed to evaluate the stocks of the elements (N, P, K+, Na+, Ca2+, Mg2+, Fe, Zn, Cu, and Mn) in roots in areas of post-pebble mining recovery in Pará, Brazil. The study was carried out in four areas, namely the area under recovery with soil bioengineering techniques (complementary construction technique and soil stabilization technique), the area under recovery with a natural regeneration process, the degraded area, and the native forest located in the municipality of Capitão Poço-PA. Roots were collected at 0-10, 10-20, 20-30, 30-40, 40-50, 50-60, 60-80, and 80-100 cm soil layers, quantified the dry biomass and contents of macro and micronutrients, and then, estimated the stocks of elements in roots. The data of the element stocks in roots were subjected to the Shapiro-Wilk normality tests and analysis of variance. Means were compared using the Tukey test at 5% significance using the SISVAR statistical software. The highest average Na+, Ca2+, and Mg2+ values in fine roots were in areas with bioengineering and native forest. The native forest presented the highest average values of macro and micronutrients in fine and thick roots. Furthermore, the lowest stocks of elements in roots were in the degraded area. However, bioengineering techniques are effective in recovering degraded soils, as vegetation cover reestablishes the balance of the soil-plant system.