藏沙蒿与多年生禾草混播对西藏沙化草地土壤酶活性和微生物生物量的影响

为分析藏沙蒿(Artemisia wellbyi)与多年生禾草混播3年的土壤酶活性和微生物生物量的含量特征，筛选出修复效果最好的混播比例，本研究采用比色和氯仿熏蒸的方法分别测定不同处理下的土壤酶活性和微生物生物量，以藏沙蒿、垂穗披碱草(Elymus nutans)和细茎冰草(Agropyron trachycaulhum)不同比例混播为处理，分别为T₁(4∶1∶2)，T₂(4∶2∶1)和T₃(5∶1∶1)，同时以未修复沙化草地为对照(CK)，并与天然草地(NG)作比较。结果表明：与CK相比，3个比例混播处理均能改善土壤理化性质、提高土壤酶活性和微生物生物量碳氮磷含量，以T₃处理的效果最好。相关性分析表明，土壤酶活性与有机质、速效钾和全氮呈正相关；土壤微生物生物量与有效磷、碱解氮和含水量呈正相关。因此，灌草混播时,适当增加灌木的占比有利于土壤养分及生物学特性的恢复。

Effects of Mixed-Sowing of Artemisia wellbyi and Perennial Grasses on Soil Enzyme Activities and Microbial Biomass of Desertified Grassland in Tibet

The characteristics of soil enzyme activity and microbial biomass content of desertified grassland mix-sown with Artemisia wellbyi and perennial grasses for 3 years were analyzed,and the mixing ratio with the best remediation effect was screened out. In this study,colorimetric and chloroform fumigation methods were used to determine soil enzyme activity and microbial biomass under different treatments. Artemisia wellbyi,Elymus nutans and Agropyron trachycaulhum were treated with different mixed sowing ratios,T₁ (4:1:2),T₂ (4:2:1),T₃ (5:1:1). At the same time,unrepaired sandy grassland was used as control (CK) and compared with natural grassland (NG). The results showed that:Compared with CK,the three proportions of mixed sowing treatments could improve soil physical and chemical properties,increase soil enzyme activities and microbial biomass，carbon,nitrogen and phosphorus contents,and the effect of T₃ treatment was the best. Correlation analysis showed that soil enzyme activities were positively correlated with organic matter,available potassium,and total nitrogen;soil microbial biomass was positively correlated with available phosphorus,alkalyzable nitrogen and water content. Therefore,properly increasing the proportion of shrubs in the mixture of shrub and grass is more conducive to the restoration of soil nutrients and biological characteristics.