Propriedades físico-hídricas de um planossolo sob sistema de integração lavoura - pecuária - floresta no agreste da Paraiba

Abstract

Integration systems, such as Crop-Livestock-Forest, emerge as an alternative to mitigate the effects of degradation, since, with the use of plant, animal and forest strata, a synergy and balance is sought in the soil and the environment. In this sense, this work aimed to evaluate the physical attributes of a Haplic Planosol in search of highlighting quality attributes under iLPF in Agreste da Paraíba after seven years of implantation. The research was conducted in an area located at the Experimental Station of the Empresa Paraibana de Pesquisa, Rural Extension and Land Regularization - EMPAER, in the municipality of Alagoinha, PB. The experimental design used was randomized blocks with five treatments and four replications. The treatments consisted of 1) Gliricidia + Brachiaria decumbens (GLI+BRA); 2) Thrush + Brachiaria decumbens (SAB+BRA); 3) Purple Ipê+ Brachiaria decumbens (IPÊ+BRA); 4) Corn + Brachiaria decumbens (MI+BRA); 5) Brachiaria decumbens (BRA). Soil samples with undisturbed and deformed structures were collected in two layers (0.00-0.10 m and 0.10-0.20 m) to determine the following variables: texture, degree of flocculation (GF), soil density (ρ), maximum (ρmax) and relative (ρR) density, degree of compaction (GCe), estimated total porosity (αEst), macroporosity (Ma), microporosity (Mi) and saturated hydraulic conductivity (KƟ). After collecting the data, they were tabulated and submitted to the Tukey test (p<0.05) and a principal component analysis (PCA) was also performed. According to the results obtained, after seven years of implementation of the integration system, it was possible to observe differences between the systems for the degree of flocculation, soil density, maximum density, relative density and degree of soil compaction. Regarding the attributes that best explained the variability of treatments based on principal component analysis (PCA), they were total porosity, macroporosity, microporosity and saturated hydraulic conductivity. There is a strong correlation between total porosity and the other related attributes, thus, it is considered essential to evaluate the physical conditions of the soil, mainly related to root volume and water conduction. The treatments that showed the greatest difference in relation to the evaluated attributes were Ipê (IPÊ) and Sabiá (SAB), justified by a greater trampling in this area. In addition, the BRA treatment alone shows lower values for all attributes, mainly the degree of flocculation, that is, the association of forests with grasses improves the physical conditions of the soil to the detriment of isolated grasses.