科尔沁沙地小叶锦鸡儿人工固沙区土壤理化性质的变化

Soil Physical and Chemical Characters Changes of Caragana microphylla Plantation for Sand Fixation in Keerqin Sandy Land

选取科尔沁沙地不同年龄的小叶锦鸡儿固沙林为研究对象,研究了在人工固沙林发育过程中土壤的颗粒组成、容重、孔隙度、持水性、透水性、养分和水分含量以及土壤酶活性等理化性质的变化。结果表明,随着林龄的增长,固沙林内土壤理化性质均得到较好的改善,土壤粘粒含量增加,表层容重变小,孔隙度增大,土壤持水性和渗透性能均有所提高,有机质、速效N、P、K的含量大幅度增加,但土壤水分含量却出现了下降的趋势。同时,随着林龄的增长小叶锦鸡儿固沙林土壤酶活性逐渐提高,20年生的土壤酶活性基本接近于天然群落,表明小叶锦鸡儿是本地区优良的固沙树种。固沙林内结皮层的酶活性总体上不高,但均高于其毗邻下层土壤,其中转化酶活性高出近20倍。

Taking different age Caragana microphylla plantations for sand fixation in Keerqin sandy land as the research object, the mechanical composition, porosity and bulk density, saturated water-holding capacity, water permeability, nutrient and water content of soil were studied in this article. The results showed that soil physical and chemical characters in sand fixation plantation were all well improved with the age increasing, and the porosity and percentage of viscosity particle of soil increased, bulk density in surface soil decreased, saturated water-holding capacity and water permeability improved, organic matter and the content of readily available N, P, K increased, while soil water content decreased. Meanwhile, the soil enzyme activities in Caragana microphylla plantation enhanced with the age increasing, and the soil enzyme activities in 20-age plantation were close to that in natural forest, thus it indicates that Caragans microphylla is a fine species for fixing sand dune in Keerqin sandy land. The enzyme activities in soil crust were higher than that of soil below the crust, among which invertase activity was almost 20 times higher than that of the soil below the crust.