Influence of intensive cropping of vegetables on physical and hydraulic properties and functions of an Oxisol in the Brazilian Cerrado

Abstract

The intensification of agricultural systems (e.g., vegetable production) to supply the food demand of the world’s population has increased over the last decades. In Brazil, the largest area of vegetable cropping systems is located in the Oxisols within the Cerrado biome. These areas are characterized by intensive land use and large-scale mechanized agriculture, which may affect the soil physical quality over time. This study aims to understand the effects of vegetable cropping (VG) systems on physical-hydric properties of highly weathered Oxisols. To this end, soil physical properties were assessed in representative VG systems of different ages [15 (VG15), 20 (VG20), and 30 (VG30) years old] and in a native Cerrado vegetation (CV), which was used as a reference of an intact system. Several analyses were conducted, including soil water retention curve, soil bulk density (ρ), soil penetration resistance (PR), saturated hydraulic conductivity (Ksat), disaggregation index, and structural stability index. In addition, a soil physical quality index (SPQI) was developed to assess the effects of soil management on soil functions and ecosystem services in the VG systems evaluated. It was observed that VG systems promoted soil compaction as indicated by the increase in ρ and PR values compared to the CV. This resulted in changes in soil porosity with mesopores being the most affected. The changes in soil porosity reduced Ksat and field capacity, and increased the permanent wilting point, leading to a reduction in available water capacity. The SPQI was reduced by 34, 32, and 43% in VG15, VG20, and VG30, respectively, compared to the CV (0.89). Based on our SPQI, support of root development and resistance to erosion and degradation were the soil functions most affected, regardless of the VG system age. Our results indicate the need to improve the current management used in VG systems to mitigate soil compaction and improve soil physical quality of Oxisols under these systems in the Brazilian Cerrado. This is essential to restore soil functionality and to ensure the sustainable food production of these systems in the long term.