Tomato Yield and Quality and Emitter Clogging as Affected by Chlorination Schemes of Drip Irrigation Systems Applying Sewage Effluent

• Published in: Journal of Integrative Agriculture Vol. 11; no. 10; pp. 1744 - 1754
• Main Authors: LI, Jiu-sheng, LI, Yan-feng, ZHANG, Hang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.10.2012; Science Press; State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin, China Institute of Water Resources and Hydropower Research, Beijing 100038, P.R.China; Elsevier
• Subjects: chlorination; chlorination drip irrigation emitter clogging fruit quality tomato sewage effluent yield; drip irrigation; emitter clogging; fruit quality; sewage effluent; tomato; yield; 二级污水; 产量; 果实品质; 氯化处理; 滴灌灌水器; 滴灌系统; 生物堵塞; 番茄; yield; emitter clogging; drip irrigation; tomato; chlorination; fruit quality; sewage effluent
• ISSN: 2095-3119; 2352-3425
• DOI: 10.1016/S2095-3119(12)60179-8

Chlorination has been recognized as an efficient and economically favorable method for treating clogging in drip emitters caused by biological growth during sewage application. Further important criteria for determining an optimal chlorination scheme are the different responses of crops to the chloride added into the soil through chlorination. During two seasons in 2008 and 2009, field experiments were conducted in a solar-heated greenhouse with drip irrigation systems applying secondary sewage effluent to tomato plants to investigate the influences of chlorine injection intervals and levels on plant growth, yield, fruit quality, and emitter clogging. Injection intervals ranging from 2 to 8 wk and injection concentrations ranging 2-50 mg L-1 of free chlorine residual at the end of the laterals were used. For the 2008 experiments, the yield from the treatments of sewage application with chlorination was 7.5% lower than the yield from the treatment of sewage application without chlorination, while the yields for the treatments with and without chlorination were similar for the 2009 experiments. The statistical tests indicated that neither the chlorine injection intervals and concentrations nor the interactions between the two significantly influenced plant height, leaf area, or tomato yield for both years. The qualities of the fruit in response to chlorination were parameter-dependent. Chlorination did not significantly influence the quality of ascorbic acid, soluble sugar, or soluble acids, but the interaction between the chlorine injection interval and the chlorine concentration significantly influenced the levels of soluble solids. It was also confirmed that chlorination was an effective method for reducing biological clogging. These results suggested that chlorination is safe for a crop that has a moderate sensitivity to chlorine, like tomato, and can maintain a high level of performance in drip irrigation systems applying sewage effluent.