Effects of water deficit on fruit quality and water productivity of citrus under plastic film mulching in Western Hubei, China

The light reflectance of films A, B, and C increased by 43.7%, 44.6%, and 6.3% respectively on sunny days compared to no mulching. Films A and B exhibited 2.2 times higher reflectivity than film C. Moderate water deficit - Japanese film (M-A) and moderate water deficit - Dupont film(M-B) treatments demonstrated the greatest improvement in citrus quality. Water deficit combined with film mulching resulted in an average increase in WUE of 10.90%-20.35% compared to full irrigation, and 8.96%-16.52% compared to no mulching. Mulching led to an average increase in citrus yield of 3.09%-16.48% compared to no mulching. The interaction between water deficit and film mulching significantly influenced both yield and WUE. From 2019-2021, M-A and M-B treatments yielded the highest citrus production, consistently demonstrating superior performance. Therefore, the better treatments would be a combination of M-A and M-B treatments, which correspond to soil moisture levels of 70% <i>θ_f</i> -80% <i>θ_f</i> during the young fruit period of citrus under mulching with films A and B. This combination was expected to enhance citrus quality, yield, and WUE. The outcome of this study may offer scientific basis and technical support for citrus irrigation management in Western Hubei, China.