杉木人工林凋落物中微生物數量對間伐的響應1)

肖文婭　費菲　刁嬌嬌　關慶偉

(南京林業大學，南京，210037)

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杉木人工林凋落物中微生物數量對間伐的響應1)

肖文婭費菲刁嬌嬌關慶偉

(南京林業大學，南京，210037)

為了明晰凋落物中微生物數量對間伐強度的響應程度，以南京溧水林場間伐7 a后25年生的杉木(Cunninghamialanceolata(Lamb.) Hook.)人工林為對象，研究了不同間伐強度對凋落物中真菌、細菌、放線菌3類微生物數量季節性變化的影響。結果表明：不同強度間伐杉木人工林下凋落物中微生物的數量隨季節變化差異顯著，微生物數量在春季期間對間伐響應最為顯著。與對照相比，春季內弱度間伐下細菌數量顯著減少了61.05%(P<0.01)；而春季內中度間伐下的真菌和細菌數量分別減少了25.32%(P<0.01)和36.14%(P<0.01)，放線菌則增加了30.97%(P<0.05)；春季內強度間伐下真菌量和放線菌數量分別增加了77.64%(P<0.05)和59.35%(P<0.01)，細菌數量減少了42.11%(P<0.01)。其中，凋落物層溫度及林下植被層Margalef指數對微生物數量的影響最為顯著。微生物數量的影響會導致凋落物向土壤中輸送的養分不同，對提高林分生產力有重要意義。

間伐強度；凋落物；真菌；細菌；放線菌；季節變化

In order to clarify the response of the microbial number to thinning intensities in the litter layer, the microorganisms’ number of fungi, bacteria and actinomycetes in litter was determined during season changes in different thinning intensities in a 25-year old Chinese fir (Cunninghamialanceolata(Lamb.) Hook.) plantation. The numbers of microorganisms in the litter were significantly different depending on the season in the different thinning intensity, especially in spring. Compared with the control, the number of bacteria in spring significantly was reduced by 61.05% (P<0.01) in the light intensity thinning. The number of fungi in litter was reduced by 25.32% (P<0.01) in middle intensity thinning in spring, and the number of bacteria was reduced by 36.14% (P<0.01), while the number of actinomycetes was increased by 30.97% (P<0.05). In high intensity thinning, the numbers of fungi and actinomycetes were increased by 77.64% (P<0.05) and 59.35% (P<0.01), respectively. The number of bacteria in spring decreased by 42.11% (P<0.01) in high intensity thinning. Among all the factors, the impact of litter layer temperature and the Margalef index of the forest floor on the numbers of microorganisms is the most significant. The differences of the numbers of microorganisms in litter will lead to different nutrients that delivered to the soil, and improve the forest productivity.

森林凋落物是森林植物在生長發育過程中新陳代謝的產物，在促進生態系統養分循環方面起著重要作用[1]。凋落物分解是生態系統物質循環和能量轉換的主要途徑，對維持森林土壤肥力有重要作用[2]。而凋落物的分解與其中的微生物種群數量關系密切[3]。

微生物數量及生物量的變化受凋落物質量、樹種組成、土壤水熱狀況等多種因素的影響[4]，與凋落物和土壤中的養分狀況[5]和元素周轉速率密切相關[6]。物種組成[7-8]不同，凋落物的質和量就不同，適于微生物生長的營養源也不同，因而微生物的種類和數量也不同[9]。凋落物組成類型的增加對凋落物中微生物數量提升作用顯著[10]。光、熱、水、氣的分布以及土壤狀況，對凋落物中微生物的結構以及多樣性也會產生一定影響[11]。……