Effects of Ridge Planting on the Distribution of Soil Water-Salt-Nitrogen, Crop Growth, and Water Use Efficiency of Processing Tomatoes Under Different Irrigation Amounts

Ridge tillage practice can enhance water storage capacity and crop production, but its integrated effects with different irrigation amounts and mechanisms to regulate crop growth remain little known. In this study, a two-year field experiment was conducted to explore the integrated impacts of irrigation and tillage practices on soil environment, crop growth, and water productivity of processing tomatoes. Three irrigation levels (full irrigation, mild water deficit, and moderate water deficit) and two tillage practices (ridge planting and flat planting) were considered in the treatments. Results indicated that ridge planting increased soil water, nitrogen, and salt content in the 0-30 cm soil layer compared to flat planting. However, the substantial increase in soil water content induced a dilution effect on salinity, which enhanced crop growth and yield production under different irrigation levels. Ridge planting improved the leaf area index (LAI), total yield, and water use efficiency (WUE) by 26.55 similar to 68.25%, 49.45 similar to 122.50%, and 54.19 similar to 124.15%, respectively. The highest total yield was achieved under ridge planting combined with mild water deficit conditions, whereas the lowest was recorded under flat planting with moderate water deficit. These findings suggest that ridge cropping optimizes the redistribution of water, nitrogen, and salt in the soil, which improves crop growth and yield. Overall, ridge planting represents a viable strategy for improving soil fertility and yield production, and promoting efficient resource utilization, particularly in water-limited regions.