Evaluation of aggregate distribution and selected soil physical properties under maizejack bean intercropping and gypsum rates

Abstract

Adequate soil management can create favourable conditions to increase aggregation and porosity of the soil, resulting in better aeration of the soil and water infiltration. Consortia of maize and other species have been used in no-till systems to increase dry matter production, and consequently, the soil cover. This study aimed to evaluate the effects of consortia of maize and jack bean (Canavalia ensiformis) on aggregate stability and soil physical properties at different depths and with different rates of gypsum. The experiment was conducted in Parana State, Brazil. The experimental design consisted of completely randomised blocks arranged in a split-plot design with four replications. The main plots consisted of maize intercropped with jack bean or not intercropped, and the subplots consisted of six rates of gypsum (0, 1, 2, 3, 4 and 5 t ha-¹). After maize cultivation, soil samples were collected for analysis of macroporosity, microporosity, total porosity, and soil bulk density at three depths. Monoliths were collected at 0-0.15 and 0.15-0.30-m depths for aggregate stability analysis. The application of gypsum promoted higher aggregate stability at the 0-0.15-m depths, but there was no effect on macroporosity, microporosity, total porosity, or soil bulk density. Maize intercropped with jack bean promoted more stable aggregates and increased macroporosity and total porosity. The use of gypsum in maize intercropped with jack bean promoted amelioration of the soil structure. The intercropping system increases the aggregate stability and macroporosity. The intercropping system also offers farmers the opportunity to improve the physical properties of the soil to benefit plant growth. In addition, intercropping maintains soil function, such as aeration, water infiltration and retention, and nutrient availability. In the long term, intercropping systems may be more stable than monocultures. Key words: Bulk density, calcium sulphate, consortium, cover plants, cropping system, macroporosity, management system, soil sustainability, Zea mays.