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以不同退耕年限下菜子湖湿地土壤和邻近原始湿地及仍耕作油菜地为研究对象,分析退耕还湖后土壤理化性质和微生物量碳氮变化。研究结果表明:随着退耕还湖年限增加,土壤容重逐渐降低,土壤含水量和粘粒含量逐渐增加,土壤有机质和全氮含量逐渐增加,而土壤全磷含量降低;表层土壤微生物量碳含量为333.77~700.75mg/kg,表层土壤微生物量氮含量为30.80~64.01mg/kg,且均有退耕还湖后升高趋势;土壤微生物量碳与土壤有机质、全氮、pH呈极显著相关(P<0.01),与土壤粘粒含量显著相关(P<0.05);土壤微生物量氮与土壤有机质、全氮、容重呈极显著相关(P<0.01),与pH显著相关(P<0.05)。分析表明,退耕还湖后随着人类活动干扰压力的减弱和湿地水文条件的恢复,自然植被也逐渐恢复,土壤理化性质朝原始湿地方向改善,促使土壤微生物量升高,但总体仍未达到原始湿地状况。
Under different lands of returning farmland, the soil physical and chemical properties and the changes of microbial biomass carbon and nitrogen of the farmland after returning farmland to lake were analyzed. The results showed that with the increase of returning farmland to lake, soil bulk density decreased gradually, soil moisture content and clay content increased gradually, soil organic matter and total nitrogen content increased, while soil total phosphorus content decreased; surface soil microbial biomass carbon content 333.77 ~ 700.75 mg / kg, and the surface soil microbial biomass nitrogen content was 30.80 ~ 64.01 mg / kg, both of which increased after returning farmland to the lake. Soil microbial biomass carbon and soil organic matter, total nitrogen and pH had a significant correlation (P <0.05). Soil microbial biomass nitrogen was significantly correlated with soil organic matter, total nitrogen and bulk density (P <0.01), and significantly correlated with pH (P <0.05). The analysis shows that with the decrease of disturbance pressure of human activities and the restoration of wetland hydrological conditions after returning farmland to lake, the natural vegetation gradually recovered, and the soil physical and chemical properties improved toward the original wetland, which promoted the increase of soil microbial biomass, but the overall did not reach the original Wetland conditions.