Short-term interactive effects of tillage system and compost rate on soya bean growth, yield, and physico-chemical characteristics of soil

Tillage systems and compost application play important roles in improving soil conditions, nutrient availability, and crop growth and productivity. Although numerous studies demonstrating that compost application and minimum tillage (MT) systems are effective in mitigating soil degradation, their interaction effects on crop performance and soil properties at various depths remain poorly explored and require further investigation. Hence, this study assessed the effect of tillage system and compost application rate on soya bean performance and selected soil physico-chemical properties under rainfed conditions in Limpopo province, South Africa. The trial was conducted using a split-plot arrangement within a randomized complete block design with three replications. Main treatments were two tillage systems [MT and conventional tillage (CT)], while the sub-treatments were three compost rates (0, 10 and 20 t ha− 1). The MT involved the use of chisel-plough to provide minimal disturbance of soil, whereas CT involved sequential use of chisel-plough, mouldboard-plough and a disc-harrow to pulverize and level the soil. Plant growth parameters, total biomass, grain yield and soil phosphorus (P) were affected by the tillage system and compost rate interaction. Grain yield from the CT plot (2061 kg ha− 1) was 62% lower than that obtained from the MT plot (3348 kg ha− 1). Higher soil organic carbon in the MT system (0.51%) than in CT system (0.43%) showed that reducing tillage intensity increases the organic matter accumulation. Tillage system, compost rate and soil depth interaction had no significant effects on selected soil properties. The results of this study indicate that while MT enhances soya bean productivity, the tillage system and compost application interaction influences grain yield and soil P, with compost application requiring careful management to prevent yield reduction.