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Lei H.,North University of China | Lei H.,Henan Key Laboratory of Water Saving Agriculture | Zang M.,North University of China | Zang M.,Henan Key Laboratory of Water Saving Agriculture | And 7 more authors.
Paiguan Jixie Gongcheng Xuebao/Journal of Drainage and Irrigation Machinery Engineering | Year: 2015

Aerated subsurface drip irrigation refers to a kind of crop irrigation method in which aerated water is ejected into the root zone of a plant by using subsurface drip irrigation (SDI) system. It can enrich air content in the water significantly and eases temporal hypoxia in the root zone of plants in clayey soil under SDI system, subsequently increases crop productivity. The effects of aerated subsurface drip irrigation on growth, yield, and quality of greenhouse tomato are investigated by using yellow clayey soil in Zhongmou County, Henan Province. Compared with the control treatment, the crop water use efficiency (WUE) in the aerated treatment is increased by 20.72%, the fruit yield is improved by 29.15% at the first five harvests, and the harvest date is moved up under the same irrigation quota. Also, the stomatal conductance of tomato is raised by 30.51% and the plant vigour is enhanced. The vitamin V content, soluble solid and sugar-to-acid ratio are increased by 13.25%, 8.62% and 22.05%, but the total acid content and fruit rigidity are decreased by 15.50% and 11.19%, respectively, suggesting the quality of tomato has been improved greatly. Furthermore, the longest root length is increased by 16.75% and the root-to-canopy dry weight ratio rises by 25.81%. The results suggest the aerated subsurface drip irrigation can promote tomato plants to grow in the yellow clayey soil in green houses, to speed the mature process of fruit, to increase the yield of crop and to improve the quality of tomato. ©, 2015, Editorial Department of Journal of Drainage and Irrigation Machinery Engineering. All right reserved. Source


Lei H.,North China University of Water Conservancy and Electric Power | Lei H.,Henan Key Laboratory of Water Saving Agriculture | Zang M.,North China University of Water Conservancy and Electric Power | Zang M.,Henan Key Laboratory of Water Saving Agriculture | And 7 more authors.
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2014

Aerated subsurface drip irrigation (ASDI) refers to the irrigation with aerated water based on Venturi principle by the use of subsurface drip irrigation (SDI) system. ASDI provides a source of oxygen to root environment that may suffer from temporary hypoxia, and therefore unlocks yield potentials of crops. But the efficiency of ASDI is dependent on a number of factors. Among which, proper operating pressure and surfactant concentration are of great significance for aeration efficiency and the uniformity of air and water flow in the aerated irrigation water stream. Proper control of air-water transmission will offer the industry an opportunity to further optimize the use of ASDI system and improve water use efficiency and minimize the environmental impacts of irrigation. The primary objective of this study was, therefore, to explore optimum working pressure and a surfactant sodium dodecyl sulfate - SDS addition on the flow uniformity of water-air irrigation in the drip pipeline. Nine combination were tested (3 working pressure at 0.05, 0.10, 0.15 MPa and 3 concentration level of SDS of 0, 5, and 16 mg/L, respectively). Each combination has aeration treatment and non-aeration treatment. Results showed that the aerated concentration was increased with increasing operating pressure even without surfactant addition. However, aerated concentration decreased with increasing operating pressure under surfactant addition. Under the same operating pressure, the aerated concentration increased with increasing surfactant concentration. The addition of surfactant significantly increased the equilibrium concentration in aeration treatment. The average value of water flow uniformity under aerated drip irrigation was greater than 95%, suggesting that there was no negative impact of surfactant addition on the water flow during oxygation. And the air flow uniformity of each combination remained above 70%. The oxygen transmission efficiency was improved with the addition of SDS. The surfactant concentration had a positive effect on the oxygen mass transfer coefficient, while the operating pressure had a negative effect on the oxygen mass transfer coefficient. The surfactant addition has greatly shortened the aeration time. The deviation between the observed and calculated aerated concentration were less than 5%, indicating that the calculation method was reliable for the aerated irrigation water stream. The operating pressure at 0.1 MPa and surfactant concentration of 5 mg/L was optimal combination. This research demonstrates great importance of the improvement of aeration efficiency and the air-water transfer for oxygation that can significantly reduce the cost of operation. ©, 2014, Chinese Society of Agricultural Engineering. All right reserved. Source

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