不同年龄小叶锦鸡儿固沙群落土壤酶活性及微生物生物量的变化

小叶锦鸡儿(Caragana microphylla)是科尔沁沙地广为采用的豆科固沙植物。为探讨采用小叶锦鸡儿固定流沙后,土壤生物活性的变化特点和发展趋势,选取5、10、22年生小叶锦鸡儿人工固沙群落为对象,以半流动沙丘和天然群落为对照,研究了人工固沙群落发育过程中土壤磷酸单酯酶、蔗糖酶、蛋白酶、脲酶、脱氢酶的活性和微生物生物量C、N、P质量分数的变化特征。土壤按5层取样:0~10,10~20,20~30,30~40,40~50cm。结果表明,随着小叶锦鸡儿固沙群落发育时间的增长,群落内土壤生物活性逐渐改善,沙土中5种酶的活性和土壤微生物生物量C、N和P质量分数均大幅度提高,其中0~10cm土层增幅最大。土壤酶中蔗糖酶的活性增加最为迅速,5、10和22年生群落0~10cm土层中蔗糖酶的活性分别是半流动沙丘的76.80,167.27和261.63倍。22年生群落的土壤生物活性已接近于天然群落,处于相对稳定的状态。小叶锦鸡儿群落中土壤酶和微生物生物量之间存在极显著的正相关关系。以上表明,小叶锦鸡儿不仅具有较好的防风固沙性能,而且表现出强大的改善土壤生物活性的能力,可作为优良的固沙植物材料在本地区大面积推广应用。

Changes of soil enzyme activities and microbial biomass in an age sequence of Caragana microphylla plantation for sand-fixation

Caragana microphylla, a leguminous shrub, is widely used in stabilize moving and semi-moving sand dune in Horqin Sandy Land. The purpose of this study is to reveal the change characteristics of biological properties of sandy soil and its development trend under the establishment of C. microphylla plantations in flowing sand dune. With semi-moving sand dune and natural community as controls, the activities of phosphomonoesterase, saccharase, protease, urease, dehydrogenase and the contents of microbial biomass C, N, P of the soil in an age sequence (5-, 10-, 22-year) of C. microphylla plantations were studied. Soil samples were taken from each and every plant community at 5 depths (0~10, 10~20, 20~30, 30~40, 40~50 cm). The results showed that the soil biological activities in sand fixation plantation were all well improved with the age increasing; the activities of the 5 enzymes and the contents of microbial biomass C, N, P were gradually increased. Among the 5 enzymes, the increase of activity of saccharase was most significant, whose measurements in 0~10 cm soil of 5, 10 and 22 age plantations were 76.80, 167.27 and 261.63 times respectively of the semi-moving sand dune. The soil biological activities in 22-year plantation were already close to that in the natural community. There existed significant positive correlation between the soil enzyme activities and the microbial biomass contents. The C. microphylla thus shows the high abilities not only for sand-fixation and wind-protection, but also for the improvement of soil biological activities, and is available to be recommended for wide use in fixing moving sand dune in the semi-arid region.