黄土高原半干旱地区尾菜高量还田的环境风险及其成本约束机制  

Environmental risk and cost restraint mechanism for incorporating large quantities of vegetable residues into fields in semi-arid area of the Loess Plateau

作　　者：张光全[1] 巴音 杜玉明 李凤民[2] 薛伟 ZHANG Guangquan;BA Yin;DU Yuming;LI Fengmin;XUE Wei(Yuzhong Agricultural Technology Distribution Center,Yuzhong 730100,China;College of Ecology,Lanzhou University,Lanzhou 730000,China;Wuhai Substation of General Environmental Monitoring Station of Inner Mongolia Autonomous Region,Wuhai 016000,China)

机构地区：[1]榆中县农业技术推广中心,榆中730100 [2]兰州大学生态学院,兰州730000 [3]内蒙古自治区环境监测总站乌海分站,乌海016000

出　　处：《中国生态农业学报（中英文）》2022年第11期1827-1841,共15页Chinese Journal of Eco-Agriculture

基　　金：国家自然科学基金项目(32001129);甘肃省农业生态环境保护专项新技术(新设备)研发推广项目(RWS-NYSTZZ202102)资助。

摘　　要：尾菜还田能够培肥低质黄土,但其高量还田是否带来环境二次污染并由此增加处理成本等问题仍不清楚。在黄土高原半干旱区,采用覆土埋压方法设计了3个尾菜高量还田厚度(20 cm、40 cm和60 cm)和3个覆土厚度(10 cm、20 cm和30 cm)随机组合的小区试验,和两个中型试验(尾菜还田厚度350 cm,覆土厚度30 cm),调查了尾菜降解率、土壤表面NH_(3)和H_(2)S排放速率、土壤重金属和农药残留量、盐离子含量以及工程成本等数据。结果显示,所有处理尾菜累积降解率均呈对数增长曲线,其表现先快后慢,第20天和第35天小区和中型试验场尾菜降解率均达70.0%以上,之后趋缓;还田尾菜厚度60 cm、覆土厚度10~30 cm,较对照全菜(60 cm厚尾菜露天堆放)的NH_(3)和H_(2)S排放量分别减少71.0%~86.0%和84.9%~87.9%。覆土表面NH_(3)排放速率时间序列均呈单窄峰值曲线,峰值大小和排放量与还田尾菜厚度呈显著正相关(P<0.05),与覆土厚度呈显著负相关(P<0.05)。小区试验覆土表面H_(2)S排放量与对照全土(翻耕0~30 cm土壤)无显著差异,但中型试验场的H_(2)S排放量明显增加。尾菜还田量越大,污染物排放强度越小;中型试验场尾菜层及其上层和下层土壤重金属、农药残留量、Ca^(2+)含量均与对照全土无显著差异,而Na^(+)向深土层淋洗。中型试验场尾菜还田量与处理成本呈幂律负相关关系,尾菜还田量越大,其处理成本越低,最低成本均值可至25.0±7元∙t^(−1)(鲜重)。因此,在黄土高原半干旱区,采用覆土埋压法高量还田尾菜是一种低成本、简便易行和生态环保的尾菜高效处理方案。The incorporation of vegetable residues can fertilize low-quality loess,but it is still unclear whether large quantity of vegetable residues incorporation will cause secondary environmental pollution and increase processing costs.In this study,a plot test was designed in the semi-arid area of the Loess Plateau in Yuzhong,which was randomly combined with three thicknesses of incorporated vegetable residues(20,40,and 60 cm),three thicknesses of surface soil covering(10,20,and 30 cm).Meantime,two mediumscale site tests were conducted,in which the thickness of incorporated vegetable residue was up to 350 cm,and the surface soil covering thickness was 30 cm.The degradation rate of vegetable residues,emission rate of NH_(3) and H_(2)S on the soil surface,residue of heavy metals and pesticides in the soil,salt ions contents,and processing cost were investigated.The cumulative degradation rate of vegetable residues in all treatments showed a logarithmic growth curve,which was first fast and then slow.On the 20th and 35th days,the degradation rate of vegetable residues reached 70.0%in the plot and the medium-scale test sites,respectively,and subsequently slowed down.When the thickness of the incorporated vegetable residues was 60 cm and the depth of covering soil was 10–30 cm,the emission of NH_(3) was reduced by 71.0%–86.0%,and the emission of H_(2)S was reduced by 84.9%−87.9%,compared with QC(vegetable residue thickness of 60 cm and no soil cover).The time series changes of the NH_(3) emission rate on the soil surface showed a single narrow peak curve,and the peak value of emission rate and cumulative emission were significantly positively correlated with the thickness of incorporated vegetable residues,and significantly negatively correlated with the depth of the covering soil.There was no significant difference in H_(2)S emissions from the soil surface of the plot test and QT(no incorporation of vegetable residues),and the H_(2)S emissions from the medium-sized test increased significantly.The larger the amount

关 键 词：尾菜 高量还田 降解率 NH_(3)排放 H_(2)S排放 成本 黄土高原 

分 类 号：S19[农业科学—农业基础科学]