Drip Fertigation Improves Maize Yield, Resource Utilization, and Economic Benefits by Increasing Light Interception Under Dense Planting in Southwest China

Seasonal drought and traditional water-fertilizer management limit the increase in the grain yield of summer maize in Southwest China. Drip fertigation mode (HM) can effectively improve crop yields. However, research on drip fertigation has not been conducted in Southwest China. A 2-year field experiment about HM was carried out with the traditional water-fertilizer management mode (FM) as control. The plant densities were 5.25 × 10⁴ plants ha⁻¹ and 8.25 × 10⁴ plants ha⁻¹ in 2022 and 6.00 × 10⁴ plants ha⁻¹ and 9.00 × 10⁴ plants ha⁻¹ in 2023. The effects of HM on the aboveground biomass, leaf area index, yield, and resource utilization rate of summer maize were studied. Compared with the FM treatment, the HM treatment significantly increased the yield (25.18%), aboveground biomass (25.58%), leaf area index (34.87%), and leaf area duration (29.60%). HM optimized the canopy structure with an 11.05% improvement in light transmission at the top and a significant 61.32% increase in cumulative light radiation interception per unit area at the bottom of the canopy. The nitrogen partial factor productivity (NPFP), radiation utilization efficiency (RUE), heat utilization efficiency (HUE), and economic benefits of the HM treatment significantly increased by 39.58%, 49.45%, 25.92%, and 32.53%, respectively. In addition, dense planting increased the irrigation water use efficiency (IWUE) by 14.25%. In summary, drip irrigation combined with water and fertilizer can significantly improve maize grain yield, resource utilization efficiency, and economic benefits by increasing light interception in Southwest China. This study will lay a theoretical foundation for filling the relevant research gap in the region.