摘要
城市污泥农用是解决污泥处理处置问题的主要措施,但也存在重金属污染等潜在风险。为探索污泥合理利用,本研究以河西绿洲灌漠土为对象,采用田间定位试验,设置了常规施肥(NP)、常规施肥+城市污泥堆肥9000 kg·hm^(-2)(NPS_(9000))、常规施肥+城市污泥堆肥18000 kg·hm^(-2)(NPS_(18000))、常规施肥+城市污泥堆肥18000 kg·hm^(-2)+复种绿肥还田(NPGrS_(18000))和常规施肥+城市污泥堆肥18000 kg·hm^(-2)+复种绿肥移除(NPGtS_(18000)) 5个处理,探讨不同处理对小麦-玉米轮作作物产量、土壤理化性状、有机碳和全氮的固存率、氮磷钾活化系数、作物产量及重金属含量的影响。结果表明:4个污泥处理的玉米产量较常规施肥差异不显著,但小麦产量较常规施肥显著增产,其中2015—2019年4个污泥处理间的小麦产量随污泥施肥年限的增加由差异显著逐渐到差异不显著。污泥施用增加了土壤有机质、全氮、全磷、碱解氮和速效磷含量,活化土壤氮磷钾,提高有机碳和全氮固存率,降低土壤pH值和容重,并随施用量的增加培肥效果更佳。污泥施用、污泥+绿肥还田土壤重金属虽略有增加,但均低于国家安全标准。NPS_(18000)处理的玉米籽粒锌和铅含量及NPGtS_(18000)处理的玉米籽粒锌含量显著高于常规施肥。施肥土壤重金属携入量远大于作物地上部分携出量。综上所述,施用污泥可显著提升土壤肥力和小麦产量,高量施用污泥与绿肥移除相结合,可抑制玉米籽粒对重金属锌和铅的吸收,增加重金属携出。为保证玉米籽粒锌和铅含量在安全范围内,污泥年携入锌和铅的量应在348 g·hm^(-2)和9.5 g·hm^(-2)以内。
Agricultural use of urban sludge is a main way for processing municipal sludge. However,such applications have the risks of heavy metal pollution. This study is aimed to explore the reasonable application of sludge by a field experiment in Hexi oasis irrigated desert soil. The experiment included five treatments: conventional fertilization( NP) as control,conventional fertilization + urban sludge compost 9000 kg·hm^(-2)( NPS_(9000)),conventional fertilization + municipal sludge compost 18000 kg · hm^(-2)( NPS_(18000)),conventional fertilization + municipal sludge compost 18000 kg · hm^(-2)+ green manure returning planted after wheat harvest( NPGrS_(18000)),and conventional fertilization + municipal sludge compost 18000 kg · hm^(-2)+ replanting green manure and removal( NPGtS_(18000)). We examined the effects of sludge and green manure application on soil physical and chemical properties,organic carbon and total nitrogen sequestration rate,nitrogen,phosphorus and potassium activation coefficient,crop yield,and heavy metal contents in a wheat-corn cropping system. The results showed that the effects of four treatments of sludge application on corn yield were equivalent to that of NP,while wheat yield was significantly increased. The difference of wheat yield in the four treatments with sludge application gradually changed from significant to insignificant with increasing duration of sludge application from 2015 to 2019. Sludge application increased the contents of soil organic matter,total nitrogen,total phosphorus,alkali hydrolyzable nitrogen and available phosphorus,activated soil nitrogen,phosphorus and potassium, increased organic carbon and total nitrogen sequestration rate, and reduced soil pH and bulk density. The application effect was positively correlated with application rate. Although sludge application or sludge + green manure returning slightly increased the accumulation of heavy metals in the soil,the contents of all heavy metals were lower than the national safety standards of China. The zinc and lead contents of corn grains in NPS_(18000) treatment and the zinc content of corn grains in NPGtS_(18000) treatment were significantly higher than those of NP treatment. The input amount of heavy metals by the sludge application was much greater than the output amount by harvesting crops. In summary,the application of sludge could significantly increase soil fertility and wheat yield. High-level sludge application combined with removal of green manure could inhibit the absorption of zinc and lead by corn grains and increase the output of heavy metals from the cropping system. To ensure that the zinc and lead contents in corn grains are below safe limits,annual input amount of zinc and lead carried by the sludge application should be lower than 348 g·hm^(-2) and 9.5 g·hm^(-2).
作者
姚佳璇
俄胜哲
袁金华
车宗贤
王钰轩
赵天鑫
YAO Jia-xuan;E Sheng-zhe;YUAN Jin-hua;CHE Zong-xian;WANG Yu-xuan;ZHAO Tian-xin(Institute of Soil Fertilizer and Water Saving Agriculture,Gansu Academy of Agricultural Sciences,Lanzhou 730070,China;College of Resources and Environment,Gansu Agricultural University,Lanzhou 730070,China)
出处
《生态学杂志》
CAS
CSCD
北大核心
2021年第7期2120-2132,共13页
Chinese Journal of Ecology
基金
国家重点研发计划项目(2017YFD0801103)
兰州市人才创新项目(2016-RC-112)
临泽县凹凸棒石产业开发课题(LZKFKT-1804)资助。
