华西雨屏区不同退耕模式细根(包括草根)分解过程中土壤酶动态  

Soil enzyme dynamics during fine root (including grass root) decomposition in different farmland-to-forest/grassland conversions in the rainy zone of western China

作　　者：荣丽[1,2] 李守剑[3] 李贤伟[1] 范川[1] 

机构地区：[1]四川农业大学林学院,四川雅安625014 [2]云南大学亚洲国际河流中心,昆明650091 [3]四川省林业勘察设计研究院,成都610081

出　　处：《植物生态学报》2010年第6期642-650,共9页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金面上项目(30771717);国家"十一五"科技支撑项目(2006BAC01A11);四川省教育厅重点实验室项目(2006ZD006);四川农业大学长江上游植被恢复与重建创新项目共同资助

摘　　要：采用原状土芯(intact core)法,探讨了四川洪雅柳江退耕模式--光皮桦(Betula luminifera)与扁穗牛鞭草(Hemarthria compressa)复合模式(HN)、扁穗牛鞭草草地模式(NC)、柳杉(Cryptameria fortunei)人工林模式(LS)、光皮桦人工林模式(H)细根(包括草根)分解过程中土壤酶动态。结果表明:1)HN下的土壤脲酶、蔗糖酶、酸性磷酸酶活性较大,LS下的土壤脲酶、酸性磷酸酶活性最小,显著低于其他模式(p<0.05)。2)HN、NC和LS下的土壤脲酶与细根(包括草根)分解速率显著相关,HN的蔗糖酶、NC的酸性磷酸酶、LS的多酚氧化酶活性与细根(包括草根)分解速率也呈显著正相关关系(p<0.05)。3)除H外,土壤脲酶活性与细根C/N、纤维素绝对含量呈显著负相关关系(p<0.05);除NC外,多酚氧化酶活性与细根纤维素绝对含量呈显著负相关关系。4)土壤脲酶活性与需氧固氮细菌或与真菌数量显著相关,HN下的土壤蔗糖酶活性与细菌和纤维素分解菌数量呈正相关关系,H与NC下的土壤酸性磷酸酶还分别与细菌和纤维素分解菌数量呈正相关关系(p<0.05)。以上结果显示:由光皮桦与扁穗牛鞭草不同生活型植物构成的复合模式有利于土壤酶活性的提高;土壤脲酶活性高低能够反映这几种退耕模式细根(包括草根)分解速率的快慢,细根(包括草根)的C/N是影响土壤脲酶活性的一个重要因素;土壤酶活性与土壤真菌、需氧固氮细菌、纤维分解菌及细菌数量有关。Aims Soil enzymes often play an important role in maintaining soil fertility and the biogeochemical cycle in soil ecosystems. Many soil enzyme studies have examined decomposition of leaf litter,but few have addressed decomposition of fine roots. Our objectives were to determine soil enzyme dynamics during fine root （including grass root） decomposition and whether variation of soil enzymes is linked to chemical composition of fine roots. Methods We placed 560 intact soil cores in nylon bags with 0.25 mm mesh in Betula luminifera-Hemarthria compressa （HN）,Betula luminifera plantation （H）,Hemarthria compressa grassland （NC） and Cryptomeria fortunei plantation （LS） for 1 year. Intact soil cores were sampled at 30,90,180,270 and 365 d from the starting date. On each sampling date,we collected fine root （including grass root） and soils from each soil core and measured decomposition rates,chemical composition of fine root （including grass root）,soil enzymes and soil microbes. Important findings Soil urease,sucrase and acid phosphatase activities were highest in HN. Soil urease and acid phosphatase activities were lowest in LS （p 0.05）. Soil urease activity in HN,NC and LS was positively correlated to root decomposition rates. Sucrase activity in HN,soil acid phosphatase activity in NC and soil polyphenoloxidase in LS were positively correlated to root decomposition rates （p 0.05）. Soil urease activity was negatively correlated to C/N and absolute content of cellulose in decomposing roots,except for H （p 0.05）. Soil polyphenoloxidase activities in HN,H and LS were negatively correlated with absolute content of cellulose in decomposing roots. The correlation between soil urease activity and the number of aerobic azotobacter and soil fungi was significant. Moreover,soil surcease activity was significant positively correlated with cellulolytic bacteria numbers in HN. Soil acid phosphatase activity in H and NC was significant positively correlated with bacte-ria and cellulolytic bacter

关 键 词：退耕还林(草) 分解 细根(包括草根) 土壤酶 

分 类 号：S154[农业科学—土壤学]