市政污泥直接施用对玉米生长和品质的影响

目的]研究市政污泥施用后对土壤和作物生长与品质的影响,为市政污泥的直接土地利用提供科学依据。方法]以玉米为试验材料,利用田间试验研究了污泥不同的施用方式(沟施、撒施、表土下20 cm施用)和施用量(30,90,200 t/hm~2)对玉米生长和品质以及土壤重金属含量的影响。结果]适量的污泥对玉米个体的生长有促进作用,施用量为30 t/hm~2时株高、单株生物量、叶片叶绿素含量、籽粒蛋白质含量均显著高于对照。表土下20 cm施用污泥在整体上较其他两种施用方式有更高的出苗率和籽粒产量,在施用量为30 t/hm~2时籽粒产量最高,为656.70 kg/667m~2,高出对照29.64%。3种施用方式下,土壤中的Cu,Zn,Pb含量及玉米籽粒中的Cu,Zn含量均随污泥施用量的增加而增加,而玉米籽粒中Pb含量与对照相比差异不显著,土壤和籽粒中重金属含量均未超过国家相关标准。以重金属浓度满足土壤环境质量标准为限制条件,推算出当地的市政污泥施用量为30 t/hm~2可以连续施用5 a。结论]施用30 t/hm~2的污泥具有良好的效果和环境效应;为了降低污泥在土壤中的局部累积而导致的胁迫效应,表土下20 cm施用和地表撒施是相对较好的方式。

Effects of Direct Application of Municipal Sludge on Growth and Quality of Zea Mays

Objective] The effects of municipal sludge application on crop growth and quality were analyzed in order to provide a scientific basis for the direct land use of municipal sludge.Methods] Using Zea mays as the experimental material, a field experiment was conducted with different modes of sludge applications (furrow application, spraying application, and application of sludge 20 cm below the surface soil) and dosages (30, 90, and 200 t/hm²) to investigate the effects of sludge application on maize growth and quality, and the accumulation of heavy metals in the soil.Results] An appropriate amount of sludge can promote the individual growth of maize, plant height, biomass, and chlorophyll content in leaves, with the protein content of maize grain being significantly higher than that in the control when the dosage was 30 t/hm². Overall, the seed germination rate and grain yield were higher than those of the other two methods when the application of sludge occurred at 20 cm below the soil surface. When the dosage was 30 t/hm², the highest grain yield was 656.70 kg/667 m², which was 29.64% higher than that of the control. The concentrations of Cu, Zn, and Pb in the soil and the concentrations of Cu and Zn in the corn kernel increased gradually with increasing applications of sludge composts. However, there was no significant change in Pb content and the content of Cu, Zn, and Pb in the soil and corn kernel did not exceed the relevant national standards. Taking the concentration of heavy metals satisfying the soil environmental quality standard as the restriction condition, it was estimated that the ideal local municipal sludge application dosage was 30 t/hm², which could be applied continuously for 5 years.Conclusion] The best environmental effect occurred when the sludge dosage was 30 t/hm²; thus, to reduce the stress effect caused by the local accumulation of sludge in soil, the application of the sludge 20 cm below the soil surface using the spraying application method was ideal.