發(fā)布時(shí)間：2018-06-12 23:28

  本文選題：馬尾松林 + 模擬N沉降��； 參考：《生態(tài)學(xué)報(bào)》2017年04期

【摘要】：模擬N沉降對(duì)森林生態(tài)系統(tǒng)的影響是當(dāng)今全球變化生態(tài)學(xué)研究的一個(gè)熱點(diǎn)問題,土壤碳庫(kù)對(duì)N沉降比較敏感,N沉降增加了凋落葉分解過程中外源N含量,間接影響凋落葉分解的化學(xué)過程并改變凋落葉分解速率,因此,研究模擬N沉降下凋落葉分解-土壤C-N關(guān)系對(duì)預(yù)測(cè)森林C吸存有重要意義。利用原位分解袋法研究了模擬N沉降下三峽庫(kù)區(qū)不同林齡馬尾松林(Pinus massoniana)凋落葉分解過程中凋落葉-土壤C、N化學(xué)計(jì)量響應(yīng)及其關(guān)系;N沉降水平分對(duì)照(CK,0 g m~(-2)a~(-1))、低氮(LN,5 g m~(-2)a~(-1))、中氮(MN,10 g m~(-2)a~(-1))和高氮(HN,15 g m~(-2)a~(-1))。結(jié)果表明:分解540 d后,N沉降促進(jìn)20年生和30年生馬尾松林凋落葉分解,46年生馬尾松林中僅低氮處理促進(jìn)凋落葉分解,4種處理均是30年生分解最快,說(shuō)明同一樹種起始N含量低的凋落葉對(duì)N沉降呈正響應(yīng),N沉降處理促進(jìn)起始N含量低的凋落葉分解,起始N含量高的凋落葉分解過程中易達(dá)到"N飽和"。N沉降抑制20年生和46年生凋落葉C釋放(低于對(duì)照0.62%—6.69%),促進(jìn)30年生C釋放(高于對(duì)照0.28%—5.55%);30年生和46年生林分N固持量均高于對(duì)照(高于對(duì)照0.15%—21.34%),20年生則低于對(duì)照(5.70%—13.87%),說(shuō)明模擬N沉降處理促進(jìn)起始C含量低的凋落葉C釋放和起始N含量低的凋落葉N固持。N沉降處理下僅30年生馬尾松林土壤有機(jī)碳較對(duì)照增加,且土壤有機(jī)質(zhì)與凋落葉C、N和分解速率呈正相關(guān),與凋落葉C/N比呈顯著負(fù)相關(guān);土壤總氮與凋落葉分解速率、凋落葉N含量呈正相關(guān),土壤有機(jī)碳/總氮比與凋落葉C、N含量呈正相關(guān);對(duì)照處理中凋落葉分解指標(biāo)對(duì)土壤養(yǎng)分影響順序是分解速率凋落物C含量凋落物C/N比凋落物N含量,低、中、高氮處理中則是凋落物C含量分解速率凋落物N含量凋落物C/N比。研究表明低土壤養(yǎng)分含量馬尾松林對(duì)N沉降呈正響應(yīng),N沉降促進(jìn)低土壤養(yǎng)分馬尾松林凋落葉分解并提高土壤肥力;凋落葉質(zhì)量和土壤養(yǎng)分含量低的生態(tài)系統(tǒng)土壤C對(duì)N沉降響應(yīng)更顯著。
[Abstract]:Simulating the effects of N deposition on forest ecosystem is a hot issue in global change ecology. Soil carbon pool is sensitive to N deposition and N deposition increases the exogenous N content in the decomposition process of litter leaves. The chemical process of leaf decomposition is indirectly affected and the decomposition rate of litter is changed. Therefore, it is important to study the relationship between litter decomposition and soil C-N under simulated N deposition in predicting forest C uptake. In situ decomposition bag method was used to study the stoichiometric response of foliage to soil Con N during leaf decomposition of Pinus massoniana, Pinus massoniana at different forest ages in the three Gorges Reservoir area under simulated N deposition. The results were as follows: (1) MN (10 g MN) and 15 g (HN ~ (2) ~ (1) ~ (1) and 15 g ~ (?) ~ (-2) ~ (?) ~ (1) ~ (1) ~ (?) ~ (1) ~ (-1), and ~ (2) A ~ (1) ~ (1) ~ (-1) ~ (-1). The results showed that N deposition promoted litter decomposition of Pinus massoniana forest in 20 years old and 30 years old after 540 d decomposition, and only low nitrogen treatment promoted litter decomposition in 46 years old Pinus massoniana forest, which was the fastest in 30 years old Pinus massoniana forest. The results showed that the litter leaves with low initial N content of the same tree species had a positive response to N deposition. It is easy to reach "N saturation" .N deposition during leaf decomposition with high N content to inhibit C release from litter leaves of 20 years old and 46 years old (lower than that of control 0.62 -6.69C, promote C release of 30-year old forest (higher than control 0.28-5.55g; 30-year-old and 46-year-old forest). The N sequestration capacity was higher than that of the control (0.15-21.34g), and the 20-year old was lower than the control (5.70-13.87g), which indicated that simulated N deposition could promote C release from litter leaves with low initial C content and N sequestration in litter leaves with low initial N content. The soil organic carbon of Pinus massoniana forest was higher than that of the control. Soil organic matter was positively correlated with Con N and decomposition rate, and negatively correlated with C / N ratio of littered leaves, and soil total nitrogen was positively correlated with litter decomposition rate and leaf N content. There was a positive correlation between soil organic carbon / total nitrogen ratio and Con N content in litter leaves, and the order of litter decomposition index on soil nutrient was that C / N content of litter was lower and lower than that of litter N in control treatment. The decomposition rate of C content in litter was C / N ratio of litter N content in litter. The results showed that the low soil nutrient content of Pinus massoniana forest was positive response to N deposition and N deposition promoted litter decomposition and improved soil fertility of Pinus massoniana forest with low soil nutrient content. The response of soil C to N deposition was more significant in ecosystem with low leaf quality and soil nutrient content.
【作者單位】： 中國(guó)林業(yè)科學(xué)研究院亞熱帶林業(yè)研究所;中國(guó)林業(yè)科學(xué)研究院森林生態(tài)環(huán)境與保護(hù)研究所國(guó)家林業(yè)局森林生態(tài)環(huán)境重點(diǎn)實(shí)驗(yàn)室;中國(guó)林業(yè)科學(xué)研究院森林生態(tài)環(huán)境與保護(hù)研究所 國(guó)家林業(yè)局森林生態(tài)環(huán)境重點(diǎn)實(shí)驗(yàn)室;南京林業(yè)大學(xué)南方現(xiàn)代林業(yè)協(xié)同創(chuàng)新中心;國(guó)家林業(yè)局秭歸森林生態(tài)系統(tǒng)定位觀測(cè)研究站;
【基金】：國(guó)家自然科學(xué)基金資助項(xiàng)目(31400531) 中央級(jí)公益性科研院所基本科研業(yè)務(wù)費(fèi)專項(xiàng)資助項(xiàng)目(CAFYBB2014QB033)
【分類號(hào)】：S714

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