Influência da adição de biochar sobre as modificações das propriedades físicas de um Latossolo Amarelo Distrófico da Amazônia Central

Abstract

Biochar has been identified as a conditioner for the physical, chemical and biological properties of the soil. In this perspective, it is reckoned that when added in the long term, this material may condition improvements in the physical properties of agricultural soils. As a result, the objective of this work was to quantify changes in the physical attributes of the soil after thirteen years of the addition of biochar in a Yellow Dystrophic Oxisol in Central Amazon. The experiment was executed at the Experimental Station of Tropical Fruit of INPA, in Manaus - AM. Increasing doses of biochar were incorporated into a Yellow Dystrophic Oxisol in 2006. The treatments B0, B40, B80 and B120, corresponded to the doses increasing 0, 40, 80 and 120 Mg ha-1 of biochar, respectively. The biochar was obtained from the metropolitan charcoal plants of Manaus, produced in artisanal ovens known as “rabo quente" which can reach temperatures of 470 ° C to 600 ° C. After 13 years of the addition of the biochar, the modifications of the physical attributes of the soil and organic carbon were evaluated, in the superficial depth (0.0 – 0.10 m) and subsurface (0.10 – 0.20 m). As a result, 128 undisturbed samples, 128 deformed samples were collected, as well as an average of 128 readings with the impact penetrometer, in the (0.0 – 0.10 m) and (0.10 – 0.20 m) layers of the soil, making a sample size (n = 16) for all variables analyzed, since it was considered 4 samples/experimental unit x 4 treatments x 4 repetitions x 2 depths. From this point, the following soil attributes were analyzed: Gravimetric humidity (Gh), Density of soil (SD), Density of soil particles (Pd), Total porosity (Tp), Resistance of soil to root penetration (RP), and Organic soil carbon (CO). All data were submitted to the Levene and Shapiro-wilk test (p < 0.05) to verify the homogeneity of the variances, and the normality of the data sets, respectively. Then an ANOVA was applied, and when there was significance, the Tukey test (p < 0.05) was applied. According to the analyzes, in the superficial layer (0.0 – 0.10 m), there was significance for the following data sets: Density of the soil particles (Pd) (p < 0.05), and Resistance of the soil to root penetration (RP) (p < 0.001). No significant differences were observed for all data sets investigated in the subsurface layer (0.10 – 0.20 m) from the ground. Thus, after 13 years the biochar affected the Density of the soil particles (Pd), and the Resistance of the soil to the penetration of roots (RP) in the superficial layer (0.0 – 0.10 m), when applied doses B40 and B80, (40 Mg ha-1 and 80 Mgha-1). However, the addition of biochar did not change the physical attributes of the subsurface layer (0.10 – 0.20 m) of the Dystrophic Yellow Oxisol.