Soil management strategies for mitigating degradation and enhancing sustainability in sloped Stagnosols under maize cultivation – first results

Conservation tillage management on rainfed croplands aims to improve the soil's physical environment, reduce soil erodibility, and enhance conservation. However, transitioning from plowing to conservation tillage can present challenges, particularly regarding soil compaction and erosion-runoff dynamics. This study comprehensively evaluates soil degradation in an area characterized by maize cultivation in Croatia on Stagnosols extremely prone to compaction and erosion. During 2024, the impacts of plowing, chisel, and subsoiling were monitored, considering soil properties, erosion, and element losses. Nine experimental plots (100 m x 8 m) were established, each equipped with a runoff and sediment collection system. Soil erosion and sediment transport were monitored throughout the maize growing season. The results reveal significantly reduced sediment concentrations by 49.1% at chisel plots compared to plowing plots, while subsoiling led to a 77.7% reduction. The highest sediment loss occurred under plowing, while chisel decreased soil loss by 73.4% and subsoiling by 95.9%. Nutrient losses followed a similar pattern. The sediment collected from plowing plots was significantly enriched with nutrients and heavy metals, compared to bulk soil, highlighting the role of soil erosion rates in nutrient depletion and pollution. In contrast, subsoiling showed no significant differences between sediment and bulk soil concentrations, reinforcing its role in reducing fine particle detachment and nutrient loss. Subsoiling significantly reduced bulk density and penetration resistance at 10-30 cm depth. The highest water-holding capacity was determined under subsoiling, i.e. it was 7.6% greater than under plowing, contributing to better soil moisture retention. The highest maize biomass yields were found (p > 0.05) under subsoiling (25.06 t ha-1); they were 11 and 19% greater than in the plowing and chisel treatment, respectively. Subsoiling significantly improves soil structure, minimizes erosion, and reduces nutrient losses, making it a viable conservation strategy for sloped agricultural landscapes. The substantially reduced sediment transport under subsoiling indicates that deep loosening enhances soil stability and infiltration, providing long-term benefits for sustainable soil management and water quality protection on Stagnosols.