ABSTRACT The method of applying fertiliser to the soil affects grain productivity. The aim of this study was to determine the dynamics of phosphorus, potassium and sulphur in the arable layer of the soil during the third year of agricultural production, as a function of the method of application. The study took place in the district of Diamantino, Mato Grosso, in an area of soybean-maize succession under minimum tillage. Five treatments were tested in a randomised block design: no phosphorus or potassium (P0-K0); broadcast phosphorus and in-furrow potassium (Pb-Kf); in-furrow phosphorus and potassium (Pf-Kf); in-furrow phosphorus and broadcast potassium (Pf-Kb); broadcast phosphorus and potassium (Pb-Kb). When the soybeans reached physiological maturity, soil samples were collected from the 0-0.05, 0.05-0.10, 0.10-0.15 and 0.15-0.20 m layers for analysis of the pH, and P, K, S and organic matter content. The soil attributes were submitted to analysis of variance and Tukey’s test at 5%, and the nutrient dynamics in the soil profile were analysed by regression. The in-furrow application of phosphorus (Pf-Kb and Pf-Kf) improved P availability in the 0-0.05 m layer by 69.12% and 46.54% compared to the Pb-Kb treatment, by 73.93% and 50.71% compared to the Pb-Kf treatment, and by 136.77% and 105.16% compared to the P0-K0 treatment. The in-furrow application of phosphate fertiliser proved to be more effective in terms of phosphorus availability in the soil. The residual effect of broadcasting phosphate fertiliser on phosphorus availability in the soil can be seen from the third year of production onwards.

Resumo: O objetivo deste trabalho foi comparar a qualidade estrutural e a curva de retenção de água de um Latossolo Vermelho-Amarelo sob arranjos de linhas simples, duplas e triplas de paricá (Ochroma pyramidale), em um sistema integrado de produção com 50 meses de implantação. O solo foi coletado em cinco pontos de amostragem em relação à distância do renque das árvores. Foram coletadas amostras indeformadas nas camadas de 0,00-0,10 e 0,10-0,20 m para avaliar porosidade, densidade, resistência do solo à penetração, curva de retenção de água no solo e índice “S”. O arranjo florestal com três linhas de paricá promoveu melhores condições físicas ao solo em comparação ao renque de linha simples. As principais alterações ocorreram na camada de 0,10-0,20 m, com aumento da microporosidade e diminuição da criptoporosidade e da resistência à penetração. Os arranjos com paricá em linhas simples e dupla resultam em maiores volumes de água indisponíveis e compactação ao solo.

Abstract: The objective of this work was to compare the structural quality and water retention curve of a Haplustox under single, double, and triple “paricá” (Ochroma pyramidale) lines in an integrated production system at 50 months of implantation. Soil was collected from five sampling points considering the distances from the tree lines. Undisturbed samples were collected from the 0.00-0.10 and 0.10-0.20-m layers in order to assess porosity, density, soil penetration resistance, soil water retention curve, and the “S” index. The forest arrangement based on three paricá lines promoted better soil physical conditions than the system using single lines. The main changes were recorded in the 0.10-0.20-m layer, with increased microporosity and decreased cryptoporosity and resistance to penetration. The arrangements using single and double paricá lines result in higher volume of available water and greater soil compaction.