黄河三角洲退化刺槐林地不同改造模式下土壤酶活性及养分特征

为探索黄河三角洲重度退化刺槐林不同改造模式的改良土壤效果,以改造后的棉田、纯林(白蜡林)、农林间作(白蜡+棉花)、混交林(白蜡+刺槐)为研究对象,未改造的重度退化刺槐林作为对照,分析比较不同改造模式下的土壤酶活性、养分特征及其相关关系。结果表明:4种改造模式对土壤养分含量和酶活性均有显著性差异,土壤剖面表层普遍高于20-40cm土层,农林间作与混交林在退化刺槐林土壤修复中具有较好的效果;棉田属于掠夺式的土地利用方式,虽能暂时提高表层土壤的养分,但不利于土壤的持续利用。磷酸酶、脲酶、多酚氧化酶及过氧化物酶和土壤养分等具有较强的相关性,可用来指示该区域不同改造模式下土壤质量的变化特征。4种改造模式土壤酶指数从大到小依次为混交林、农林间作、纯林、棉田。从土壤酶活性和养分特征等改良土壤效应来看,混交林和农林间作改造模式较好,其次为纯林,棉田不宜作为长期营建方式。

Soil Enzyme Activities and Nutrient Characteristics of Different Improving Patterns in the Yellow River Delta Area

In order to explore the soil improvement impact by different improving patterns including cotton field,pure forest of Fraxinus chinensis,agro-forestry of F.chinensis+cotton,mixed forest of F.chinensis+Robinia pseucdoacacia and unimproved heavy degradation experiment as a comparison on badly degraded Robinia pseucdoacacia plantation in Yellow River Delta area,soil enzyme activities,nutrient characteristics and their relationship under different improving patterns were analyzed comparatively.The results showed that significant differences existed in soil nutrient and soil enzyme activity,agro-forestry and mixed forest had better effects in the restoration of degraded soil.Planting cotton was predatory ways in land use.It was disadvantageous to the sustainable land use.On the whole,phosphatase,soil urease,polyphenol oxidase and peroxidase showed stronger positive correlations with soil nutrient,which can be an indicator of evolution characteristics of soil quality under different improving patterns in this area.The SEI changed with an order of mixed forest >agro-forestry >pure forest >cotton field.Soil enzyme activity and physicochemical properties of mixed forest and agro-forestry were better than pure forest or cotton filed.Therefore,it’s proposed that mixed forest and agro-forestry should be fostered and managed firstly in the future.