土壤pH和SO_(4)^(2−)含量对设施菜地土壤障碍强还原处理修复的响应  

Response of Soil pH and SO_(4)^(2−)Content to Remediation by Reductive Soil Disinfestation in Degraded Greenhouse Vegetable Soil

作　　者：赵旭丽 姚宇阗 陈超 黄新琦[3] 孟天竹 ZHAO Xuli;YAO Yutian;CHEN Chao;HUANG Xinqi;MENG Tianzhu(College of Agricultural Science and Engineering,Hohai University,Nanjing 210098,P.R.China;Jiangsu Coast Development Group Co.,Ltd.,Nanjing 210000,China;School of Geography,Nanjing Normal University,Nanjing 210023,P.R.China)

机构地区：[1]河海大学农业科学与工程学院,江苏南京210098 [2]江苏省沿海开发集团有限公司,江苏南京210000 [3]南京师范大学地理科学学院,江苏南京210023

出　　处：《生态环境学报》2023年第7期1218-1225,共8页Ecology and Environmental Sciences

基　　金：国家自然科学基金项目(U21A20226);国家重点研发计划项目(2020YFD0900705)。

摘　　要：设施蔬菜地常面临硫酸根(SO_(4)^(2−))累积等次生盐渍化问题。强还原土壤消毒方法(Reductive Soil Disinfestation,RSD)能够有效改良退化土壤,但RSD处理过程中SO_(4)^(2−)转化产物及RSD对次生盐渍化的长期改良效果尚不清楚。为探究土壤初始pH和SO_(4)^(2−)含量对RSD处理过程中SO_(4)^(2−)去除效果、转化产物及种植作物过程中土壤理化性质的影响,设置5个处理:无处理对照、淹水+紫花苜蓿粉(RSD)、RSD+石灰调节土壤pH至7.30、RSD+SO_(4)^(2−)(添加量为4000 mg·kg^(−1))、RSD+石灰+SO_(4)^(2−)(同上),处理结束后盆栽种植二茬黄瓜(Cucumis sativus L.),每个处理3个重复。结果表明,RSD处理后,土壤pH显著升高,EC值降低,土壤可溶性SO_(4)^(2−)-S含量降低了330-728 mg·kg^(−1),未施和施用SO_(4)^(2−)处理可溶性SO_(4)^(2−)含量分别降低了83.6%-93.3%、35.0%-42.1%。未施SO_(4)^(2−)处理中土壤总硫和SO_(4)^(2−)沉淀含量基本不变,吸附态SO 42−含量略有降低,表明减少的SO_(4)^(2−)主要转化为有机态硫,且施用石灰提高土壤pH可促进SO_(4)^(2−)转化为有机硫。土壤在晾干和后续种植作物过程中,RSD处理转化的有机硫再次矿化为SO_(4)^(2−),导致土壤盐分回升和pH值降低。种植一茬黄瓜后,各处理SO_(4)^(2−)含量已上升至处理前水平。同时,RSD处理后由于NO3−的完全脱除土壤面临缺氮风险,种植过程中施用了大量铵态氮肥,导致土壤进一步酸化和次生盐渍化。种植两茬黄瓜后,各处理土壤pH值降低了2.02-2.36,EC值增加了0.201-0.233 mS·cm−1。综上,对于SO_(4)^(2−)初始含量高的土壤,由于有机硫迅速矿化,RSD处理后土壤将面临盐分回升及再次盐渍化风险。RSD处理后应选用合适的肥料品种结合科学施肥方式,以维持RSD处理对土壤次生盐渍化的长期改良效果。Sulfate(SO_(4)^(2−))is usually accumulated in intensively used greenhouse soil and thus causes secondary soil salinization.Although it is widely reported that reductive soil disinfestation(RSD)can effectively improve degraded soils,the transformation products of SO_(4)^(2−)during RSD and its long-term improvement effects remain unclear.To investigate the effects of liming and soil SO_(4)^(2−)content on SO_(4)^(2−)removal efficiency and its transformed products during RSD process,as well as the changes in soil chemical properties during replanting process,five control or treatment groups were set up:no-treatment control(CK),flooded soil amended with alfalfa(RSD_(0)),soil with pH adjusted to 7.30 by limed RSD_(0)(RSD_(1)),RSD_(0) added with 4000 mg kg^(−1) sulfate(RSD_(2)),and limed RSD_(2)(RSD_(3)).After RSD treatment,two seasons of cucumber were planted.The results showed that soil pH increased and electric conductivity(EC)decreased significantly after the RSD treatments,and the soil soluble SO_(4)^(2−)-S content decreased by 330‒728 mg·kg^(−1) in the RSD treatments.The removal efficiency of soluble SO_(4)^(2−)in RSD_(0),RSD_(1),RSD_(2) and RSD_(3) was 83.6%,93.3%,35.0%,and 42.1%,respectively.The contents of soil total sulfur and SO_(4)^(2−)precipitate were unchanged,while soil adsorbed SO_(4)^(2−)contents decreased in the RSD_(0) and RSD_(1) treatments.Hence,the decreased SO_(4)^(2−)was mainly transformed into organic sulfur(S),and liming promoted the transformation process.During the subsequent soil air drying and replanting processes,the organic S re-mineralized into SO_(4)^(2−),which led to the increase in soil EC and decrease in pH,The soil SO_(4)^(2−)contents increased to their initial value in the RSD treatments after planting the first season of cucumber.Since nitrate was almost totally removed after RSD,a large amount of ammonium nitrogen fertilizer was applied during the replanting process,which further led to soil acidification and salinization again.Soil pH decreased by 2.

关 键 词：土壤退化 强还原土壤修复方法 土壤酸化 土壤次生盐渍化 石灰 SO_(4)^(2−)转化 

分 类 号：S156.99[农业科学—土壤学] X171.1[农业科学—农业基础科学]