灌溉水质和灌水方式对红壤斥水性及其理化性质的影响

以蒸馏水为对照,选取再生水和稀释2,4,6倍再生水等4种低质水,采用连续灌溉和再生水-蒸馏水交替灌溉等2种灌溉方式对红壤进行1年的处理,以此探明灌溉水质和灌水方式对酸性土壤斥水性、pH、盐分及有机质质量比的影响.结果表明:2种灌溉方式下红壤均产生亚临界斥水性,连续灌溉下红壤接触角比交替灌溉平均增加了23.1°;2种灌溉方式均使红壤酸性增强,盐分和有机质质量比增加,其中连续灌溉下的增长率大于交替灌溉下增长率;连续灌溉下红壤斥水性、pH、盐分和有机质质量比随灌溉水质的变化均可用二次函数来描述,决定系数均在0.9以上;交替灌溉下,红壤斥水性和盐分与灌溉水质的关系可用二次函数来表示,决定系数均在0.9以上,而土壤pH和有机质质量比与灌溉水质相关性不明显;2种灌溉方式下,红壤斥水性与pH呈负相关,与盐分质量比呈正相关,与土壤有机质质量比在连续灌溉下表现为正相关,而交替灌溉下则相反.采用再生水-蒸馏水交替灌溉方式能抑制土壤斥水性的产生.

Effects of different water quality and irrigation methods on red soil water repellency and physical-chemical properties

In order to research the effect of different irrigation methods and water quality on acidic soil water repellency, pH, salt and organic matter content, four kinds of low-quality water such as reclaimed water and diluted 2, 4, 6 times of reclaimed water were selected, distilled water as contrast, using reclaimed water for continuous irrigation as well as alternate irrigation with reclaimed water and distilled water to do red soil column infiltration exreriments for more than 1 year. Results show that induction of subcritical water repellency following different irrigation with reclaimed water, the contact angle of red soil under the continuous irrigation grew by an average of 23.1° as against alternate irrigation. Both irrigation methods increase the acidity of red soil as well as salt and organic matter content, and the growth rate under continuous irrigation is larger than that of alternating irrigation. In the continuous irrigation, the soil water repellency, pH, salt and organic matter content can be described by quadratic function with the change of water quality, and the determination coefficient is above 0.9. In the alternate irrigation, the relationship between red soil water repellency, salt and water quality can be described by quadratic function, and the determination coefficients are all above 0.9, but the soil pH and organic matter content have no obvious correlation between it. In the two irrigation conditions, soil water repellency is negatively correlates with pH, it is positively correlates with salt content, and it is negatively correlates with organic matter content in the continuous irrigation, while in the alternate irrigation it is opposite. The alternate irrigation with reclaimed water and distilled water can restrain the generation of soil water repellency.