论文部分内容阅读
采用树脂芯法将哀牢山中山湿性常绿阔叶林内土壤分别移植到中海拔的次生林和低海拔的人工林下培养,并以原地培养为对照,对土壤氮素转化的海拔效应进行了研究。土壤氮素的净矿化速率、净硝化速率和淋溶速率受季节和海拔的影响极为显著(P<0.01)。海拔的影响在雨季前期最显著,高海拔土壤的净矿化和净硝化速率分别为-5.81和-4.18mgN·kg-1·60d-1,移植到中、低海拔培养后,净矿化速率分别为20.92和44.15mgN·kg-1·60d-1,净硝化速率分别为17.07和20.38mgN·kg-1·60d-1,淋溶量也分别增加了0.37倍和2.77倍。由于雨季中后期反硝化作用增加导致净矿化和净硝化速率降低,导致高、中海拔培养的土壤净氮矿化速率在雨季中期达到最高值,雨季后期降低。由此可推断,未来的气候变暖很可能会加快哀牢山中山湿性常绿阔叶林土壤氮素的转化速率和气态损失量。
The soil in the middle evergreen wet evergreen broad-leaved forest in Ailao Mountain was transplanted into the secondary forest at mid-elevation and the artificial forest under low altitude respectively by resin core method. The in-situ culture was used as the control to study the elevation effect of soil nitrogen transformation the study. Net nitrogen mineralization rate, net nitrification rate and leaching rate were significantly affected by season and altitude (P <0.01). The effects of altitude were most significant in the pre-rainy season. Net mineralization and net nitrification rates were -5.81 and -4.18mgN · kg-1 · 60d-1, respectively. After transplanting to middle and low altitudes, the net mineralization rate Respectively, 20.92 and 44.15mgN · kg-1 · 60d-1, the net nitrification rates were 17.07 and 20.38mgN · kg-1 · 60d-1, leaching increased by 0.37 and 2.77 times respectively. Due to the increase of denitrification in the middle and later rainy season, the net mineralization and net nitrification rate decreased, which resulted in the net nitrogen mineralization rate reaching the highest value in mid-rainy season and lower in late rainy season. It can be inferred that the future climate warming is likely to speed up soil N conversion and loss of soil in the evergreen broad-leaved evergreen forests in Ailao Mountain.