摘要:有机物还田是提升土壤肥力的主要措施，但也存在造成土壤金属污染的潜在风险。为查明不同有机物还田对土壤质量及作物产量的影响，本文通过长期定位试验，研究了无肥对照、常规施化肥（氮磷配施）以及70%常规化肥与牛粪、沼渣、污泥、鸡粪、菌渣和猪粪配施对土壤理化性状、有机碳和氮的固存率、氮磷钾活化系数、作物产量及重金属含量的影响。结果表明：牛粪、沼渣、污泥、菌渣、鸡粪和猪粪与70%化肥配施虽作物产量与常规施化肥相似，但6种有机物处理土壤有机质、全氮和碱解氮含量都较常规施化肥处理显著增加，污泥、鸡粪和猪粪处理土壤全磷与速效磷含量较常规施化肥处理显著增加，而且牛粪、沼渣、鸡粪和猪粪处理的速效钾、土壤磷活化系数和土壤钾活化系数较常规施化肥处理也显著提升。牛粪、沼渣、污泥、菌渣、鸡粪和猪粪处理土壤有机碳固存率为36.42%~71.61%，较常规施化肥处理都显著提高；而其氮固存率为6.47%~49.44%，仅有菌渣处理与常规施化肥处理差异不显著，而其他处理较常规施化肥处理显著增加。长期施鸡粪和菌渣处理的土壤铜含量较常规施化肥处理显著增加，增加量分别为4.17 mg·kg-1和14.2 mg·kg-1；而污泥、鸡粪和菌渣处理的土壤锌含量较常规施化肥处理显著增加，增加量分别为13.53 mg·kg-1、22.60 mg·kg-1和49.73 mg·kg-1。综上，等有机质（4 500 kg·hm-2）的牛粪、沼渣、污泥、菌渣、鸡粪和猪粪可替代30%氮磷肥，作物产量不受影响；不同有机物培肥土壤效果为污泥、鸡粪和猪粪优于牛粪和沼渣，而沼渣的培肥效果略差。为保证土壤环境质量稳定不恶化，种植小麦时有机物铜和锌的年携入量应分别低于53.01 g·hm-2和221.30 g·hm-2，而种植玉米时应分别低于153.40 g·hm-2和347.04 g·hm-2。
关键词:有机物/
作物产量/
土壤理化性状/
活化系数/
固存率/
重金属
Abstract:The Hexi Corridor is a famous irrigated agricultural area in Northwest China. However, ecological weakness and heavy long-term chemical fertilizer application has caused problems such as low organic matter content, soil structure degeneration, and low crop yield. Returning organic materials into the field is the main solution to improve soil fertility; however, it also risks causing heavy metal pollution in the soil. This study aimed to explore the effect of soil quality and crop yield response to different types of applied organic materials in the field. The long-term positioning experiment consisted of 8 treatments:no fertilizer (CK) as control, conventional fertilizer (NP), 70% conventional fertilizer respectively, with cow dung (0.7NP+NF), with biogas residue (0.7NP+ZZ), with sewage sludge (0.7NP+WN), with chicken manure (0.7NP+JF), with mushroom substrate residue (0.7NP+JZ), and with pig manure (0.7NP+ZF). We studied how partially replacing chemical fertilizers with different organic materials affected the physical and chemical soil properties, soil organic carbon sequestration efficiency, total nitrogen; the activation coefficients of nitrogen, potassium, and phosphorus, as well as crop yield, and heavy metal content. The results showed that the effect of annual applications of organic materials with 70% chemical fertilizer on yield was equivalent to that of NP of wheat and corn. Compared with NP the soil organic matter, total nitrogen, and available nitrogen content significantly increased under six organic materials treatments; the total phosphorus and available phosphorus content of sludge, chicken manure, and pig manure treatments significantly improved; and the available potassium content, soil phosphorus activity, and soil potassium activity of cow manure, biogas residue, and chicken and pig manure treatments also significantly improved. The organic carbon soil sequestration rate of cow dung, biogas residue, sewage sludge, mushroom substrate residue, and chicken and pig manure treatments were 36.42%-71.61% significantly higher than that of NP. While, the nitrogen soil sequestration rate was 6.47%-49.44% significantly higher than NP, except the mushroom residue treatment. Long-term applications of chicken manure and mushroom substrate residue significantly increased the total copper content by 4.17 mg·kg-1 and 14.2 mg·kg-1, respectively; sludge, chicken manure, and mushroom substrate significantly increased total content of zinc by 13.53 mg·kg-1, 22.60 mg·kg-1, and 49.73 mg·kg-1, respectively. In conclusion, applications of 4 500 kg·hm-2organic materials could replace 30% nitrogen and phosphorus fertilizer without reducing the crop yield. The degree that different organic materials affected soil fertilization was varied; sewage sludge, chicken manure, and pig manure were better than cow manure and biogas residue, while mushroom substrate residue was slight worse. When planting wheat, the annual carrying capacity for copper and zinc from organic materials should be less than 53.01 g·hm-2 and 221.30 g·hm-2, respectively. When planting corn, the annual carrying capacity of copper and zinc from organic matter should be lower than 153.40 g·hm-2 and 347.04 g·hm-2, respectively, to allow soil environmental quality to be stable without deteriorating.
Key words:Organic material/
Crop yield/
Soil physical and chemical properties/
Activation coefficient/
Sequestration rate/
Heavy metal
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