有机管理对不同土地利用方式下土壤质量的影响

Effect of organic management on soil quality under different land use types

许多研究发现有机管理可以改善农田土壤质量,但是否不同土地利用方式下都存在此结论尚未明确。为探究有机管理对不同土地利用方式土壤质量的影响,本研究基于一个多土地利用方式的有机管理农场及其附近常规管理农田进行土壤质量调查,对比不同管理措施及大棚菜地、果园、露天菜地、农田边界、稻田田埂5种土地利用方式下农田土壤质量的差异,并对不同管理措施下农田土壤养分含量、重金属含量、动物数量共计20个指标进行方差分析和主成分分析。研究发现虽然总体上(综合5种土地利用方式的均值)有机管理的土壤pH显著高于常规农田;但针对一种土地利用方式,只有露天菜地和农田边界的土壤pH显著提高。总体上有机管理下土壤全磷、全钾、有效磷含量显著降低,但露天菜地土壤有机质和全氮含量均显著高于常规管理农田。有机管理在总体上显著降低了土壤Cr、Cu、Ni、Zn含量;但针对一种土地利用方式,只显著降低了大棚菜地土壤Cr、Ni、Zn含量,果园和稻田田埂土壤Cu含量,露天菜地和农田边界土壤Zn含量。有机管理虽然总体上均显著增加了土壤中蜘蛛目、倍足纲、步甲、蚯蚓的数量;但针对一种土地利用方式,只显著增加了露天菜地地表蜘蛛目、倍足纲、步甲,稻田田埂地表步甲、土壤蚯蚓以及果园倍足纲数量。主成分分析结果表明,不同管理方式下土壤质量差异明显,有机管理下蜘蛛目、倍足纲、步甲和蚯蚓等土壤动物较多,土壤pH较高,土壤P含量较低,重金属Cu、Pb、Zn、Cr含量较低,但并非在所有土地利用方式下都成立。由此可见,有机管理虽然总体上可以改善土壤质量,但受具体管理措施、人为投入品数量和有机种植时间等因素影响,并非在所有土地利用方式下效果都显著,且在不同土地利用方式下显著改善的指标也各不相同,因此需要针对不同土地利用方式和不同指标采取针对性的改善措施。

The soil quality of farmlands can be improved by organic management,but this conclusion is unclear under different land-use types.A soil quality survey based on an organically managed farm with diversified land use and nearby conventionally managed farmland was conducted by analyzing differences in the soil quality under two different management measures within five land use types(greenhouse vegetable fields,orchards,open-air vegetable fields,farmland boundaries,and paddy ridge).Analysis of variance(ANOVA)and principal component analysis of 20 indicators of soil nutrients contents,heavy metals contents,and soil animal numbers were used to explore the impact of organic management on soil quality under different land use types.The results showed that the pH value of the organic management was significantly higher than that of conventional farmland overall(the average value of five land use types).Meantime,the organic management overallly significantly decreased soil contents of total P,total K,available P,total Cr,total Cu,total Ni,and total Zn;and increased amounts of soil Araneae,Diplopoda,ground beetle and earthworm,compared with the conventional management.But for the specific land use type,pH increased significantly in the open-air vegetable field and farmland boundary under organic management.The organic matter content and total nitrogen contents of the open-air vegetable fields,and the quantities of Araneae,Diplopoda,ground beetles,and earthworms in the soil under organic management were higher.The total Cr,total Ni,and total Zn contents in the greenhouse vegetable fields,total Zn contents in the open-air vegetable fields and farmland boundaries,total Cu contents in orchards and paddy ridges were lower.The numbers of ground beetles and earthworms in the paddy ridge,and Diplopoda in the orchard were higher under organic management.Principal component analysis indicated that there was a significant difference in soil quality under different management practices.The numbers of Araneae,Diplopoda,ground beetles,and earthworms in the soil were higher,and the pH values and contents of P,Cu,Pb,Zn,and Cr were lower under organic management.These results show that the soil quality was better under organic management,but this was not universal for all land use types due to factors such as the specific management practices,the number of artificial inputs,and the length of organic planting time.The extent to which land quality had been improved under different land use types differed,so it is necessary to take targeted soil improvement measures under diverse land use types.