Reducing Irrigation and Increasing Plant Density Enhance Both Light Interception and Light Use Efficiency in Cotton under Film Drip Irrigation

High-density planting is an effective technique to optimize yields of mulched cotton. On the other hand, deficit irrigation emerging water-saving strategy in cotton cultivation, especially suitable for arid and water-scarce areas. However, relationships between irrigation, high-density planting, regulation mechanisms canopy light radiation use efficiency (LUE) not yet clear. To clarify mechanism interception (LI) LUE canopies, three treatments [315 (50% Fc), 405 (75% Fc, farmers’ practice), 495 mm (100% where Fc was field capacity] with plant densities [13.5, 18.0 (farmers’ 22.5 plants m2] were applied. The findings this research revealed that, under above-ground dry matter (ADM) reduced by 5.05% compared practice. Over both years across all densities, LI decreased 8.36% 4.79%, respectively, relative practices. In contrast, highest level increased 10.59% 5.23%, respectively. case interaction (plant density level), ADM combination 7.69% control × sowing practices effects). also exhibited increase 1.63% 6.34%, Notably, effect middle upper film drip reached 70%. A lower resulted a higher percentage region. leaf area index, rate, extinction coefficient escalated density. Under treatment, 0–30 cm high settings 8.6% conclusion, improved canopy. These may help farmers their agricultural management strategies water-deficient