Integrated Effects of Irrigation Amounts, Fertilizer Types, and Tillage Practices on Crop Growth, Yield, and Fruit Quality of Processing Tomato

Irrigation effects on processing tomato have been comprehensively studied, whereas the integrated effects of irrigation and agronomic measures lack systematic investigations. This study employed a two-year field experiment to investigate the interactive effects of irrigation, fertilizer, and tillage practices on the crop growth, total yield, and fruit quality of processing tomato. The experimental treatments comprised three irrigation levels (full irrigation, mild water deficit, and moderate water deficit), combined with two fertilizer strategies (synthetic fertilizer only and partial substitution of synthetic fertilizer with manure), and two tillage practices (ridge planting and flat planting). It was found that the partial organic fertilizer substitution and the ridge planting significantly improved the total tomato yield by 13.11% and 75.54% on average, respectively, compared to the synthetic fertilizer application and flat planting, although they led to more salt accumulation in the top soil layer. However, the extent of the increase greatly varied over different irrigation levels and years. The mild water deficit led to a yield increase of 9.22% compared to full irrigation, while the moderate water deficit resulted in an obvious yield loss of 25.95%. Moreover, the ridge planting, the partial organic fertilizer substitution, and water deficit had strong positive effects on the fruit quality and the tillage–irrigation interaction had strong effects on the fruit quality, but it showed negligible effects on the tomato yield. In contrast, the tomato yield was very sensitive to the fertilizer–irrigation interaction, while the fruit quality showed nonsignificant sensitivity to the tillage–irrigation interaction. Finally, the combination of ridge planting, partial organic fertilizer substitution, and a mild water deficit was highlighted as a sustainable cropping production system for processing tomato to achieve an enhanced total yield and fruit quality.