再生水水质和灌溉模式对红壤阳离子交换性能的影响

选取再生水原液及其稀释2,4,6倍作为灌溉水源,设置再生水单一灌溉(4种处理RW,RW-2,RW-4,RW-6)、再生水-蒸馏水交替灌溉(4种处理ARW,ARW-2,ARW-4,ARW-6)2种灌溉模式,以蒸馏水灌溉(CK)为对照,对红壤阳离子交换性能的影响进行研究.结果表明:与CK处理比较,单一灌溉模式下各处理交换性K⁺,Na⁺,Mg²⁺的累积含量分别平均提高了121.08%,520.65%和16.22%,且随着再生水稀释倍数增大呈减小趋势,这种趋势以交换性K⁺表现最显著;再生水-蒸馏水交替灌溉模式下各处理交换性Na⁺,Mg²⁺的累积含量分别平均提高了997.45%和18.89%,而交换性K⁺没有累积现象.两种灌溉模式下各处理的土壤阳离子交换量(CEC)均未显著高于CK(p>0.05).除了处理RW-4,RW-6的碱化度(ESP)差异不具有统计学意义外,其余处理显著高于CK(p<0.05),且同一灌溉模式下ESP随稀释倍数增大而减小,同种水质交替灌溉下ESP均高于单一灌溉,表现出弱碱性或非碱性(ESP<10%).南方红壤地区采用再生水-蒸馏水交替灌溉将提高土壤次生盐碱化的潜在风险,而再生水单一灌溉可适度降低风险.

Effect of reclaimed water quality and irrigation modes on cation exchange performances of red soil

The original reclaimed water solution and its diluted 2,4,and 6 times were selected as the irrigation water source,and irrigation with distilled water(CK)as control.Two irrigation modes named single irrigation with reclaimed water(4 treatments RW,RW-2,RW-4,RW-6)and alternate irrigation with reclaimed water and distilled water(4 treatments ARW,ARW-2,ARW-4,ARW-6)were used to study the effect on cation exchange performances of red soil.The results show that compared with CK treatment,the exchangeable K⁺,Na⁺ and Mg²⁺ accumulated contents of each treatment under single irrigation mode increase by 121.08%,520.65%and 16.22%on average,respectively,and decrease with the increase of dilution ratio of reclaimed water,the exchangeable K⁺ show the most significant trend.Under alternate irrigation mode of reclaimed water and distilled water,the accumulated contents of exchangeable Na⁺ and Mg²⁺ increase by 997.45%and 18.89%on average,respectively,while exchangeable K⁺ does not accumulate.Under the two irrigation modes,the soil ca-tion exchange capacity(CEC)of each treatment is not significantly higher than that of CK(p>0.05).Except for RW-4 and RW-6,the alkalinity(ESP)of the other treatments is significantly higher than that of CK(p<0.05),and ESP decreases with the increase of dilution ratio under the same irrigation mode.Under the same water quality alternative irrigation,the ESP is higher than that under single irrigation,showing weak alkaline or non-alkaline(ESP<10%).In the red soil region of Southern China,the potential risk of soil secondary salinization will be increased by using the alternative irrigation of reclaimed water and distilled water,while the single irrigation of reclaimed water can moderately reduce the risk.