元阳梯田核心区森林群落土壤微生物数量与养分含量的分布特征

Soil Microorganisms Quantities and Nutrients Contents of Different Forest Communities at Core Zone in Yuanyang Terrace

选取元阳梯田核心区箐口和大鱼塘两地共7种森林群落(臭牡丹群落、杉树群落、茶树-旱冬瓜群落、旱冬瓜群落、鼠麴草群落、五眼果群落和鸭公树-木荷群落),按0-20cm、20-40cm、40-60cm和60-80cm土层取样,测定各土层微生物数量(细菌、放线菌、自生固氮菌、纤维分解菌和真菌)与养分含量(全N、全P、全K、碱解N、速效P和速效K),分析微生物数量与养分含量间的相关性。结果表明:(1)除茶树-旱冬瓜群落的真菌数量和旱冬瓜群落的放线菌、自生固氮菌以及纤维分解菌的数量不随土层深度的增加发生变化,其它森林群落微生物数量均随土层深度增加而减少。不同群落不同种类微生物数量变化梯度不一致。(2)鸭公树-木荷群落细菌数量最多;杉树群落的放线菌数量最多;自生固氮菌数量在旱冬瓜群落最多;纤维分解菌和真菌数量在臭牡丹群落最多。(3)7种森林群落的全N、碱解N、速效P、速效K含量均随土层深度的增加而减少,无眼果群落和鸭公树-木荷群落的全N、碱解N和速效K含量最高;旱冬瓜群落的全P和速效P的含量最高。(4)全N和3类速效养分含量与土壤微生物数量存在显著或极显著正相关。土壤微生物数量和养分含量在不同的森林群落表现出显著差异,并具有显著的垂直分布特征。

Soil sampleSwere collected in 0-20cm,20-40cm,40-60cm and 60-80cm soil depth in seven typical forest typeSat core zone in Yuanyang Terrace,and the quantitieSof soil bacteria,actinomyces,azotobacter,cellulose decomposing bacteria and fungi,in addition with the contentSof total N,P,K,available N,P and K were measured.The resultSshowed:(1)The quantitieSof fungi from Camellia sinesis-AlnuSnepalensiScommunity,and the quantitieSof actinomycetes,azotobacter and cellulose-decomposing bacteria from AlnuSnepalensiScommunity did not change with the increase of soil depth,but the quantitieSof microorganismSin other communitieSdecreased with the increase of soil depth.The gradientSof microbial changeSin different communitieSwere different.(2)The quantity of bacteria in Neolitzea chui Merr.- Schima superba community waSthe largest,the quantity of actinomyceteSin Cunninghamia lanceolata community waSthe largest,the quantity of azotobacter waSthe largest in AlnuSnepalensiScommunity,and the quantity of cellulolytic bacteria and fungi waSthe largest in Clerodendrum community.(3)The contentSof total N,alkali-hydrolyzed N,available P and available K in seven forest communitieSdecreased with the increase of soil depth,and the contentSof total N,alkali-hydrolyzed N and available K were the highest in ChoerospondiaSaxillariScommunity and Neolitzea chui-Schima superba community.The contentSof total P and available K in AlnuSnepalensiScommunity were the highest.(4)The total N and three available nutrientSwere positively correlated with soil microbial biomass,soil microbial biomasSand nutrient content showed significant differenceSin different forest communities,and had significant vertical distribution characteristics.