不同刈割年限天然草地土壤呼吸特性研究

摘要

To provide a theoretical basis for research on meadow balance of carbon budget, the effects of 4 different mowing types on soil respiration and soil microorganism are studied by detecting Hulunbeier meadow characters of soil respiration and soil microorganism. Results indicate that mowing influenced the soil respiration, carbon and nitrogen content of microorganism. In the four different mowing years of natural meadows, the highest soil respiration rate appears from noon to 14 p.m. For control areas, the highest value is 4. 874 mg · m-2 · h-1 ; in the two years of cutting areas, 4. 603 mg · m-2 · h-1 ; one year of cutting areas, 4.230 mg · m-2 · h-1 ; the three years of cutting areas, the lowest value is 4. 154 mg · m-2 · h-1. With the increasing years of cutting, the soil respiration rates show a trend of decreasing. The content of microbial carbon, nitrogen, soil enzyme activity (except for urease) and microorganisms, topsoil (0 ～10 cm; the most active, the largest number), all of them have shown to decrease with soil depth increasing. Microorganism quantities are consistent with soil respiration rates. The highest content of carbon and nitrogen appears in two years cutting areas, and also the other three enzymes (except for urease with irregular activity). The soil respiration rates are positively correlated with microbial carbon, nitrogen, protease, invertase, catalase and microorganisms, but negatively correlated with urease.%通过对呼伦贝尔草甸草原土壤呼吸特性及土壤微生物的测定,研究4种不同刈割方式对天然草地土壤呼吸特性及土壤微生物的影响,为草甸草原碳收支研究提供基础理论依据.结果表明:刈割对天然草地土壤呼吸速率、微生物量碳氮、土壤酶活性和微生物数量存在一定影响.4种不同刈割年限的天然草地土壤呼吸速率的口最高值均出现在12:00-14:00之间,对照区最高为4.874 mg·m2·h1,两年刈割区为4.603 mg·m-2·h-1,一年刈割区为4.230 mg·m2·h-1,三年刈割Ⅸ最低为4.154 mg·m-2·h-1;随着刈割年限的增加土壤呼吸速率呈现降低趋势.土壤微生物量碳、氮含量、土壤酶活性(除脲酶)以及微生物数量在表层(0～10 cm)含量最高(活性最强、数量最多),均表现出随土壤深度增加而降低(活性下降、数量减少).微生物数量变化规律与土壤呼吸速率变化结果一致,而微生物量碳、氮含量则是两年刈割区最高,除脲晦其他3种酶也是两年刈割区酶的活性最强,而脲酶各层酶活性变化不规律.土壤呼吸速率与微生物量碳、氮,蛋白酶、转化酶、过氧化氢酶、微生物数量呈正相关,与脲酶呈负相关.