施用污泥堆肥对草莓生长及土壤重金属的影响

Effects of application of sewage sludge on heavy metal in soil and strawberry growth

通过施用污泥堆肥盆栽种植草莓,研究施用不同比例(0%、5%、10%和20%)的城市污泥堆肥对土壤及草莓果实重金属含量的影响以及土壤重金属生物有效态的变化,为污泥堆肥在农业利用方面提供相关理论支撑。实验结果表明:不同污泥堆肥施用比例处理草莓产量大小顺序为:5%>0%(CK)>10%>20%(死亡),污泥堆肥施用比例为5%时,草莓果实的产量(鲜重)达最大值每株5.34 g,高出CK处理32.32%。施肥土壤中的重金属Cu、Zn、Pb、Cr和Cd等含量均随污泥施用比例的增加而呈差异显著水平增加。对比2015年1月27日和3月24日2次采摘的草莓果实重金属含量,第二次采摘的果实Cu、Zn含量比第一次采摘的果实含量有不同程度的增加,而Pb、Cd和Ni含量有不同程度的降低。在污泥堆肥施用比例为5%时,施肥土壤以及草莓果实中的重金属含量均未超过国家相关标准。种植植物后施肥土壤中重金属Cu和Zn的生物有效态增加,重金属Pb、Ni的生物有效态降低。因此,适量施用污泥堆肥能有效增加草莓产量,5%的施用比为草莓种植的最佳施肥比例。

A pot-scale test involving strawberry plants was carried out to investigate the effects of sewage sludge compost on heavy metal accumulation in soil and different batches of harvested strawberries. Furthermore,the a- mount of change in heavy metal bio-availability after planting was analyzed to reveal the acceptability of land ap- plication of sewage sludge composts. Sewage sludge composts were mixed with soil in different ratios of weight of sewage sludge compost to total weight of soil （0% ,5% , 10% , and 20% ）. The different batches of strawberries were harvested at different times （January and March 2015,respectively）. The results showed that strawberry yields after applying different ratios of sewage sludge compost were in the following order：5% 〉 CK 〉 10% 〉 20% （death）. When the sludge compost mix ratio was 5% , strawberries reached weights of up to 5.34 g per plant,32.23% higher than with CK treatment. The soil contents of heavy metals Cd, Cr, Cu, Pb, and Zn in- creased gradually with increasing application of sewage sludge composts. The content of heavy metals in the first and second strawberry harvests differed,with the second strawberry batch having higher Cu and Zn contents,but lower Pb,Cd,and Ni contents. However,Cd,Cr,Cu,Ni,Pb,and Zn contents in soil and strawberries did not ex- ceed the national standards when the ratio of sewage sludge compost was 5%. The bio-availability of Cu and Zn increased in soil after planting,but that of Ni and Pb decreased. This study indicated that soil nutrient con.tents and strawberry yields could be effectively improved when the ratio of sewage sludge compost was 5%.