规模化猪场粪水对周边盐碱地重金属及营养素含量的分析研究

The Analysis and Research of Nutrients and Heavy Metal in Manure Biogas Slurry and Saline Soil Surrounding the Large-scale Pig Farms

随着畜禽养殖业向规模化、集约化的方向发展,养殖生产中的粪便大幅度增加,其中,猪粪中含有的氮、磷、钾等营养元素以及重金属含量较高,直接排放土壤中极易造成重金属含量超标。研究以某规模化猪场储粪池的猪粪水为试验材料,周边盐碱地为研究对象,按每667 m^2设计猪粪年度总施用量15 m^3(C1)、30 m^3(C2)、45 m^3(C3)、60 m^3(C4)4个梯度,试验盐碱地面积625 m(225 m×25 m),计算盐碱地面积所对应施用量分别为14.1、28.1、42.2、56.2 m3,同时设置空白对照处理组(CK),猪粪水在2015年的4、7、8和11月分4次平均施入。研究结果表明,施用猪粪水后,土壤pH和容重均产生改变,对照组土壤的pH约为10.5,施入猪粪水后pH8.5～9。施用猪粪水后土壤电导率趋于升高,与对照组比,升高1.25～1.77 ms·cm-1,并且随着猪粪水施用量以及月份增加;施入猪粪水后,4、7、8和11月的土壤中的有机质和N、P、K元素含量均随着施用猪粪量的增加而增加;施用猪粪水后的土壤中重金属含量已超标,11月猪粪水富集在土壤中的重金属明显高于4、7、8月,不同浓度猪粪水灌溉增加土壤重金属Hg、Pb、Cu、Cr、Zn、Cd、As的含量,短期内重金属存在局部超标的可能。综上所述,盐渍化土壤施用猪粪水增加土壤养分含量的同时又增加了重金属含量的富集,其有利有弊,需要进一步的对猪粪水改良盐碱土做深入研究。

With the development of livestock and poultry breeding in the direction of scale and intensification,the feces in the production of pig manure increased greatly.Among them,the nutrient elements such as nitrogen,phosphorus,potassium and heavy metals in pig manure were higher.It is easy to cause heavy metal content to exceed the standard in the direct discharge soil.In this study,the pig dung water of a large scale pig manure storage pond was used as the experimental material,the peripheral saline soil was used as the research object,and the total annual application amount of pig dung was designed as 667 m2(25 m×25 m).The saline-alkali soil area of the experiment was 15 m3(C1),30 m3(C2),45 m3(C3),60 m3(C4),respectively.Meanwhile,the blank control group was set up as control group,and the pig dung water was applied in four times in April,July,August and November of 2015.The results showed that the pH and bulk density of soil changed after application of pig manure water.pH of soil in control group was about 10.5,and that of control group was about 8.5-9 after application of pig manure water.Soil electrical conductivity tended to increase after application of pig manure water compared with the control group.The range of increase was 1.25 to1.77 ms·cm-1 and it was increased with the increase of pig manure and the month.After applying pig manure,the contents of organic matter and N,P and K in soil in April,July,August and November increased with the increase of pig manure.The heavy metal content in the soil after applying pig manure has exceeded the standard.In November,the heavy metals in the soil were obviously higher than that of April,July and August.The content of heavy metals including Hg,Pb,Cu,Cr,Zn,Cd and As in soil was increased by the different concentration of pig manure water,and there was a possibility of partial exceeding the standard in the short term.To sum up,the application of pig dung water to salinized soil not only increased the nutrient content of soil,but also increased the enrichment of heavy metal content,which had advantages and disadvantages,so it is necessary to further study the improvement of saline-alkali soil with pig dung water.