【摘要】 以兰州南部山区林草地不同利用方式——陡坡耕地、陡坡撂荒(1年、5年和10年)和撂荒辅以人工造林(30年)为对象,研究不同利用方式对林草地主要植被种类和盖度、土壤化学特性(有机质、全氮、碱解氮和速效钾等)和微生物量(碳、氮和磷)的影响。结果表明,不同利用方式下的植被种类、植被盖度差异较大,撂荒辅以人工造林(30年以上)物种丰富度和盖度最高,撂荒10年次之,撂荒1年最小且形成以蒿类为主的不稳定杂类草群落。土壤有机质、全氮、碱解氮和速效钾含量:撂荒辅以人工造林(30年)>撂荒10年>撂荒5年>撂荒1年>陡坡耕地;土壤速效磷、pH值和CaCO3含量:陡坡耕地>撂荒1年>撂荒5年>撂荒10年>撂荒辅以人工造林(30年)。随耕地年限的增加,土壤微生物量碳和氮变化趋势相似,即:撂荒辅以人工造林(30年)>10年>撂荒5年>荒撂1年>陡坡耕地;土壤微生物量磷含量的变化趋势:撂荒辅以人工造林(30年)>陡坡耕地>撂荒10年>撂荒1年>撂荒5年。土壤微生物量碳、氮与有机质、全氮及碱性氮呈极显著正相关(P<0.01),与碳酸钙、速效磷呈显著负相关(P<0.05),微生物量磷与碳酸钙呈显著负相关(P<0.05)。更多还原

【Abstract】 Characteristics of plant species and coverage,soil chemical properties(soil organic matter,total nitrogen,available nitrogen and available potassium etc.)and microbial biomass[soil microbial biomass carbon(SMBC)and nitrogen(SMBN)]of different utilization types including sloping farmland(SF), abandoned(1,5and 10year)and 30-year-abandoned with forestation(30AF)were invested in Forestgrassland of Lanzhou South Region.The results showed that plant species and coverage had great difference for different utilization types.Utilization type of 30AF had the highest plant abundance and coverage, followed by 10year abandoned(10AF)and 1-year abandoned(1AF)had least plant abundance and coverage and formed an unstable artemisia dominated community.Soil organic matter,total nitrogen,available nitrogen and available potassium contents decreased with the following orders:30AF>SF>10AF>5AF> 1AF,however,available phosphorus,pH and CaCO3 contents decreased with the following orders:SF> 1AF>5AF>10AF>30AF.SMBC and SMBN decreased in following orders:30AF>10AF>5AF> 1AF>SF.Soil microbial biomass phosphorus(SMBP)decreased with the following orders:30AF>SF> 10AF>1AF>5AF.The Pearson correlation analysis indicated that SMBC and SMBN presented significant positive relationship(P<0.01)with organic matter,total nitrogen,available nitrogen and remarkable negative relationship with available P and CaCO3(P<0.05).There was a significantly negative relationship between SMBP and CaCO3(P<0.05).更多还原