Improving Water Productivity Using Subsurface Drip Irrigation in the Southwest Monsoon Area in Yunnan Province of China

Due to the influence of the Asian southwest monsoon, seasonal drought is serious and water resources are scarce in the Yunnan province of Southwest China. More effective water-saving irrigation methods should be developed to solve the problem of water scarcity in the dry season. In this study, a subsurface drip irrigation method was used to improve the water productivity of tomato cultivation. Deficit irrigation was conducted. We controlled the lower limit of soil moisture at three different levels (55 similar to 65%, 65 similar to 75%, and 75 similar to 85% of the field capacity). The results indicated that the subsurface drip irrigation treatment significantly increased tomato height in the later stage of tomato growth. Due to the buried pipes, the root/shoot ratio was 8 similar to 18% higher for subsurface drip irrigation than for surface drip irrigation methods. Though the yields using subsurface drip irrigation methods were slightly lower than those obtained using surface drip irrigation methods, the tomato quality and water productivity improved significantly. The subsurface drip irrigation methods improved the water productivity by 8.5 similar to 21.8% at different soil moisture levels and improved the chlorophyll content by 9.1 similar to 17.3%. The VC, soluble sugar, soluble solids, and the ratio of sugar to acid increased by 6.5 similar to 15.2%, 7.3 similar to 21.6%, 4.1 similar to 6.6%, and 3.2 similar to 20.8%. This study also indicated that by optimizing the irrigation methods and patterns, water productivity and fruit quality could be improved by more than 50%. This research will be helpful for guiding irrigation during the drought season in the southwest monsoon area in Asia.