造林对沙地土壤微生物的数量、生物量碳及酶活性的影响

Effects of Afforestation on the Abundance,Biomass Carbon and Enzymatic Activities of Soil Microorganism in Sandy Dunes

对科尔沁沙地流动沙丘中林龄为20年左右的樟子松(Pinus sylvestris var.mongolica)和小叶杨(Populus simonii)人工林表层土壤微生物数量、微生物生物量碳和酶活性进行了研究,流动沙丘作为对照。研究表明:樟子松和小叶杨人工林可以显著改善流动沙丘土壤性状,对沙丘土壤微生物活性具有显著的促进作用;土壤微生物数量、微生物生物量碳和酶活性均表现为小叶杨林>樟子松林>流动沙丘。樟子松和小叶杨林地土壤微生物总数分别是对照的50.16倍和72.48倍,三者差异显著;樟子松和小叶杨林地土壤微生物生物量碳分别是对照的23.67倍和33.34倍,林地与对照差异显著;两种林地土壤脱氢酶、过氧化物酶、蛋白酶、脲酶、纤维素酶活性分别是对照的19.00倍和27.54倍、4.78倍和9.89倍、4.05倍和8.67倍、29.93倍和37.46倍、9.66倍和13.42倍,林地与对照差异显著。在科尔沁沙地,人工种植适合当地气候特点的乔木,不仅可以改善流动沙丘土壤性状和微生物活性,而且还能起到固定流动沙丘的目的,樟子松和小叶杨是当地值得推广种植的防风固沙树种。土壤微生物量商(Cmic∶C)是一个衡量林地土壤稳定性和有效性较好的指标,从林地土壤养分有效性、林木稳定性和可持续性等方面综合考虑,樟子松比小叶杨更具优势。

In order to investigate the effects of afforestation on soil microbial abundance, microbial biomass carbon and enzymatic activities in sandy dunes, around 20-year-old Pinus sylvestris var. mongolica （PSM） and Populus simonii Carr. （PSC） mature forests were selected in Horqin Sandy Land, and mobile dunes were set as controls （CK）. The results showed that PSM and PSC plantation could improve soil physiochemical properties and increase microbiological activities significantly. Soil microbial abundance, microbial biomass carbon and enzymatic activities showed an order of PSC^PSM^CK. Soil total microbial abundance in PSM and PSC were 50.16 and 72.48 times of that in CK, and the differences were significant among PSM, PSC and CK. Soil microbial biomass carbon in PSM and PSC were 23.67 and 33.34 times of that in CK, and the difference was insignificant between PSM and PSC. Soil enzymatic activities, including dehydrogenase （DEH）, peroxidase （PER）, protease （PRO）, urease （URE） and cellobiohydrolase （CEL） activities in PSM and PSC were 19.00 and 27.54, 4.78 and 9.89, 4. 05 and 8.67, 29.93 and 37.46, 9.66 and 13.42 times, repectively, of that in CK. Pinus sylvestris var. mongolica and Populus simonii Carr. are both efficient tree species to improve soil physiochemical and microbiological properties in sandy land, and moreover, they are both efficient tree species to fix mobile dunes in Horqin Sandy Land. Cmic ： C ratio is an efficient indica- tor to estimate soil stability and availability, and based on an overall consideration of plantation stability and sustainability, Pinus sylvestris var. mongolica was better than Populus simonii Carr. to fix mobile dunes in sandy land.