有机无机改良剂对滨海盐渍化土壤酶活性和土壤微生物量的影响

目的]为解决滨海地区土壤盐分高和生态环境恶劣的问题,研究发酵园林废弃物与膨润土不同比例配合施用对滨海盐渍土的改良效果。方法]通过滨海地区田间试验,采用单独施用68 kg/m~3发酵园林废弃物(T_1)、单独施用15 kg/m~3膨润土(T_2)和二者混合施用(T_3)的方法,分析不同处理组土壤酶活性、微生物量碳、氮的变化及其与土壤理化性质的相关关系。结果]有机无机改良剂混施(T_3)在提高土壤酶活性和微生物量碳、氮方面具有更显著的效果。脲酶、蔗糖酶和脱氢酶分别为对照的10.1,9.0和4.5倍;土壤微生物量碳、氮分别比对照提高了24.8%和78.1%。此外,混施也可以显著改善土壤理化性质,使土壤盐分降低了62.7%,养分各项指标增幅为57.2%～101.4%。同有机改良剂处理相比,无机改良剂对土壤酶活和土壤微生物量的影响较小。速效钾与速效氮是影响土壤酶活性与微生物量的主要因子,而含盐量、容重则与土壤酶和微生物量呈负相关,具有抑制作用。结论]发酵园林废弃物的加入对土壤酶活性和微生物量的增加起到了决定性的作用。最佳施用处理组为原土混合掺拌68 kg/m~3发酵园林废弃物和15 kg/m~3膨润土。

Effects of Organic and Inorganic Amendment on Soil Enzyme Activities and Soil Microbial Biomass in Coastal Salinized Soils

Objective] We investigated the effects of different proportions of garden waste compost and bentonite for improving coastal saline soil. This was in order to formulate suitable amendments for solving the problems of high soil salinity and poor ecological environments in coastal areas.Methods] Through field trials in a coastal area, changes in soil enzyme activity, microbial biomass carbon, and nitrogen in different treatment groups were measured, and their correlations with soil physical and chemical properties were analyzed. This was achieved by applying 68 kg/m³ compost garden waste (T₁) alone, 15 kg/m³ bentonite (T₂) alone, and a mixed application of compost garden waste and bentonite (T₃).Results] The mixed application (T₃) had a more significant effect on increasing soil enzyme activity and microbial biomass carbon and nitrogen. Urease, sucrase, and dehydrogenase activities were 10.1, 9.0, and 4.5 times greater than the control, respectively. The soil microbial biomass carbon and nitrogen increased by 24.8% and 78.1%, respectively, compared to the control. In addition, mixed application could significantly improve the soil physical and chemical properties:soil salinity decreased by 62.7% and nutrient indicators increased by 57.2% to 101.4%. Inorganic amendments had less effect on soil enzymes and soil microbial biomass compared to organic amendments. The available potassium and available nitrogen were the main factors affecting soil enzymes and microbial biomass, whereas salt content and bulk density were negatively correlated with soil enzymes and microbial biomass.Conclusion] The addition of garden waste compost played a decisive role in increasing soil enzyme activity and microbial biomass. The best application treatment group was 68 kg/m³ of garden waste compost with 15 kg/m³ of bentonite.