沼渣施用对花生小麦轮作作物产量及土壤养分和重金属含量的影响

为研究沼渣施用对花生小麦轮作作物产量及土壤养分和重金属含量的影响,试验共设置6种施肥处理,每个处理都施750 kg/hm²复合肥为底肥,1.5×10⁴ kg/hm² (A1)、3.0×10⁴ kg/hm² (A2)、4.5×10⁴ kg/hm² (A3)、6.0×10⁴ kg/hm² (A4)、7.5×10⁴ kg/hm² (A5)、对照CK不施沼渣(A6),分析了不同处理作物产量、籽粒重金属含量、土壤养分和重金属含量。试验结果表明：施沼渣的花生产量比对照增产幅度为4.74%~9.03%,处理A2、A3、A4、A5的产量比对照A6增产差异显著(P<0.05),施沼渣的小麦产量比对照增产幅度为3.08%~7.38%,处理A2、A3、A4、A5的产量比对照A6增产差异显著(P<0.05),处理A2的花生和小麦产量都比对照A6的增产差异显著,且沼肥用量最低,是适宜的沼肥用量;与不施肥相比,沼肥显著增加了土壤养分含量,土壤有机质、全氮、有效磷、速效钾含量变幅分别为56.80~107.23 g/kg、0.26%~0.45%、93.77~128.67 mg/kg、218.33~329.67 mg/kg;花生籽仁和小麦籽粒中均未检测出Hg和As,Pb、Cd和Cr含量的变幅分别为0.023~0.07、0.11~0.23、0.015~0.062 mg/kg,均低于《食品安全国家标准食品中污染物限量》(GB 2762—2017)的标准;不同处理土壤Hg、Pb、Cd、Cr和As含量分别为0.046~0.061、23.4~29.7、0.09~0.22、71.1~89.5、12.0~14.4 mg/kg,远低于国家《土壤环境质量 农用地土壤污染风险管控标准（试行）》(GB 15618—2018)标准值。

Effects of Biogas Residue Application on Nutrient and Heavy Metal Content in Soil and Yield of Crops Under Peanut-wheat Rotation

To study the effects of biogas residue application on nutrient and heavy metal content in soil and yield of crops under peanut-wheat rotation, field experiments were carried out including six fertilizer treatments, i.e., 1.5×10⁴ kg/hm² (A1), 3.0×10⁴ kg/hm² (A2), 4.5×10⁴ kg/hm² (A3), 6.0×10⁴ kg/hm² (A4), 7.5×10⁴ kg/hm² (A5) and no biogas residue treatment (CK, A6), with the application of 750 kg/hm² compound fertilizer as basal fertilizer in each treatment. The grain yield of crops, the heavy metal content in grains, and the soil nutrient and heavy metal content were determined respectively. The results showed that the yield of peanut using biogas residue increased by 4.74% to 9.03% compared with that of the control, the yield of A2, A3, A4 and A5 was significantly higher than that of control (A6) (P<0.05); the yield of wheat using biogas residue increased by 3.08%-7.38% compared with that of the control, the yield of A2, A3, A4 and A5 was significantly higher than that of control (A6) (P<0.05); treatment A2 had significantly higher yield of peanut and wheat compared with that of A6, and the lowest biogas residue using amount, so it was the appropriate application amount of biogas residue. Compared with no biogas residue application, the addition of biogas residue significantly increased soil nutrients’ content, the content variation range of soil organic matter, total nitrogen, available phosphorus, available potassium was 56.80-107.23 g/kg, 0.26%-0.45%, 93.77-128.67 and 218.33-329.67 mg/kg, respectively. Hg and As were not detected in peanut or wheat grains, and the content of Pb, Cd and Cr changed in the range of 0.023-0.07, 0.11-0.23 and 0.015-0.062 mg/kg, respectively, all lower than The National Food Safety Standard Maximum Levels of Contaminants in Foods (GB 2762—2017). The soil content of Hg, Pb, Cd, Cr and As was 0.046-0.061, 23.4-29.7, 0.09-0.22, 71.1-89.5 and 12.0-14.4 mg/kg, respectively, all were lower than The Soil Environmental Quality - Agricultural Land Soil Pollution Risk Control Standard (Trial) (GB 15618—2018).