Alterations of physical-chemical attributes of a vertisol in a melon production area

ABSTRACT Water quality and soil quality are of great importance for crop yield in the context of small-scale irrigated agriculture in the Northeast region of Brazil. In this respect, this study aimed to determine changes in soil fertility and resistance to root penetration caused by fertigated cropping, as compared to soil under native forest. In each area, a non-regular sampling grid was established, which consisted of 87 georeferenced points in the melon cultivated area and 8 points in the native forest area. At these points, samples were obtained at depths of 0-10, 10-20, 20-30 and 30-40 cm. The determinations performed included soil physical, chemical and mechanical attributes. Multivariate analysis techniques and geostatistical procedures were used to analyze and interpret the data. The cultivation of the Vertisol altered all the variables studied, compared to the area under native forest. Soil decompaction and increase in phosphorus content were positive effects, while organic matter decomposition and reductions in potassium, calcium, magnesium and cation exchange capacity were negative effects. Sodium content and porosity parameters were prominent factors in soil alterations.