沼液还田对土壤-作物系统重金属累积的影响:Meta分析

为探讨沼液还田方式、还田时长和重金属带入量等对土壤-作物重金属累积的影响，明确重金属累积影响因素的重要性，对41篇文献和1972对数据进行整合分析.结果表明，单施沼液使土壤As、Cd、Cr、Cu、Zn和作物As、Cr的累积显著提高20.5%、15.2%、25.6%、18.7%、26.3%和14.6%、39.5%，对作物其它重金属累积作用不明显.沼液与化肥混施可显著提高8.05%和4.70%的土壤Cr和Zn的累积且降低作物对As的累积.相关分析表明，土壤As、Cd和Cr的累积速率与沼液还田时长和土壤有机质（SOM）含量呈极显著正相关（P<0.01），相关系数分别为0.30、0.15、0.13和0.22、0.27、0.22，而与土壤pH值呈极显著负相关（P<0.01），相关系数分别为0.16、0.13和0.11.沼液还田带入的重金属会促进土壤As、Cd、Cr和作物As、Cd、Cr、Zn的累积，而土壤Cd、Cu和Zn的累积又会促进作物Cd、Cu和Zn的累积，其间相关系数分别为0.45、0.58和0.42.因子重要性分析表明，沼液还田对土壤-作物系统中重金属累积的主要因素是还田时长、SOM和土壤pH值.

Effect of Biogas Slurry Return to Field on Heavy Metal Accumulation in Soil-crop System: A Meta-analysis

To investigate the effects of biogas slurry return-to-field methods, the duration of biogas slurry return to field and the amount of heavy metals brought in from biogas slurry on the accumulation of heavy metals in soil-crop systems, and the importance of factors influencing heavy metal accumulation, 41 papers and 1972 pairs of data were integrated and analyzed. The results showed that the application of biogas slurry alone significantly increased the accumulation of As, Cd, Cr, Cu, and Zn in soil and As and Cr in crops by 20.5%, 15.2%, 25.6%, 18.7%, and 26.3% and 14.6% and 39.5%, respectively, and it had no significant effect on the accumulation of other heavy metals in crops. The combined application of biogas slurry and chemical fertilizers significantly increased the accumulation of soil Cr and Zn by 8.05% and 4.70% and decreased the accumulation of As by crops. Correlation analysis showed that the accumulation rates of soil As, Cd, and Cr were highly significantly and positively correlated (P<0.01) with the duration of biogas slurry return to field and soil organic matter (SOM) content, with correlation coefficients of 0.30, 0.15, and 0.13 and 0.22, 0.27, and 0.22, respectively; they were highly significantly and negatively correlated (P<0.01) with soil pH, with correlation coefficients of 0.16, 0.13, and 0.11, respectively. The heavy metals brought in by biogas slurry return to field promoted the accumulation of As, Cd, and Cr in soil and As, Cd, Cr, and Zn in crops, whereas the accumulation of Cd, Cu, and Zn in soil promoted the accumulation of Cd, Cu, and Zn in crops, with correlation coefficients of 0.45, 0.58, and 0.42, respectively. The main factors of heavy metal accumulation in the soil-crop systems were the duration of biogas slurry return to field, SOM, and soil pH.