摘要：
Aerated irrigation can effectively alleviate the oxygen stress in the plant root zone and improve the environment of the plant root zone.This study investigated the effect of the addition of surfactant BS1000 in saline irrigation water on water and oxygen transmission under pure oxygen aerated irrigation.The oxygen transmission characteristic was investigated by using a Mazzei air injector,pressure swing adsorption oxygen generator and Seair diffuser coupled system (AirSep-SeairMazzei).Micro-bubbles produced by the AirSep-Seair-Mazzei system provide a good opportunity for its application in the long-distance aerated irrigation because of slow buoyancy characteristics and high dissolved oxygen concentration.The dissolved oxygen (DO) and temperature of water tank and drip tap were monitored by a dissolved oxygen meter.For simulating saline irrigation water,0.1 mol/L NaCl solution was prepared.Four B S 1000 concentrations were also prepared (0,1,2 and 4 mg/L).Therefore,a total of 8 combinations of NaC1 and BS 1000 were designed.During the experiment,oxygen transfer coefficient,DO saturation,flow uniformity coefficient and DO uniformity coefficient were determined.The results showed that the addition of B S 1000 had a positive effect of oxygen transfer process,and resulted in an increase of the DO saturation.The DO saturation of the irrigation water averaged 299.87％ under pure oxygen aeration.Under the addition of BS 1000 in the aerated irrigation,an increase of the BS1000 concentration caused an increase of the oxygen transfer coefficient,while a decrease of the DO saturation.The oxygen transfer coefficient of 2 and 4 mg/L BS 1000 was 22.76％ and 46.90％ higher than that of 1 mg/L BS1000,respectively,under the condition without NaCl addition.Under the addition of NaC1 in the aerated irrigation water,the high surfactant concentration (not less than 2 mg/L) would result in a large oxygen transfer coefficient.The addition of NaC1 could inhibit the DO saturation.The DO saturation in treatments of surfactant BS1000 of 0,2 and 4 mg/L with NaCl addition was decreased by 5.55％,4.92％ and 6.57％,respectively,compared to the treatment without NaC1.The average value of flow uniformity coefficient under the aerated irrigation was greater than 95％ and the DO uniformity coefficient of each combination remained above 97％.The high DO had a positive effect of the growth of crop when the oxygen concentration in soil water was lower than the upper limit demanded by crop.The oxygen transfer coefficient was greater than 18.85％ (P＜0.05) under the addition of surfactant BS1000.The DO saturation was the highest in the treatment with 1 mg/L BS1000 regardless of NaC1 addition.And all the treatments had high uniformity.Therefore,the surfactant concentration of 1 mg/L was suggested.This research demonstrates the great importance of uniform transmission of super-oxygenated water in drip tap and provides a method support for a wide range of aerated irrigation application.%曝气灌溉可有效调节植物根区环境、改善土壤通气性.微咸水中NaC1的存在及活性剂添加对提高曝气灌溉的氧传质效率,实现节能高效的灌溉有重要作用.为研究NaC1介质及生物降解活性剂对纯氧曝气灌溉水氧传输特性的影响,该文采用变压分离制氧技术-氧气扩散系统-空气注射技术耦合系统,分析NaC1介质(未添加和添加)及生物降解活性剂BS1000(醇烷氧基化物质量浓度0、1、2、4 mg/L)2个因素对氧总传质系数、溶氧饱和度、流量均匀系数和溶氧均匀系数的影响.结果表明:BS1000的添加促进氧传质过程的发生,提高了曝气水中的溶氧饱和度;随着BS1000浓度增加,氧总传质系数逐渐增加,而溶氧饱和度呈现下降的趋势;BS1000质量浓度在2 mg/L,及以上时,NaCl介质对氧总传质系数的增幅显著;NaC1介质对曝气水中的溶氧饱和度起到抑制作用.各组合条件下,曝气滴灌中流量均匀系数均在95％以上,溶氧均匀系数均在97％以上.添加活性剂BS1000可使氧总传质系数平均提高18.85％以上(P＜0.05).无论添加NaC1与否,添加1 mg/LBS1000的溶氧饱和度均最大,故1 mg/L BS1000是适宜的活性剂添加浓度.
