【摘要】：采用靜態(tài)箱-氣象色譜法,測定不同間伐強(qiáng)度溫帶棄耕地落葉松人工林(未間伐為對照、輕度間伐強(qiáng)度為25%、重度間伐強(qiáng)度為50%,林齡50年及間伐已20年)及相應(yīng)立地上農(nóng)田的土壤溫室氣體(CO_2、CH_4和N_2O)排放年通量與相關(guān)環(huán)境因子(土壤溫度、濕度及養(yǎng)分含量等),揭示造林與間伐對棄耕地土壤溫室氣體排放的影響規(guī)律,以便為定量評價(jià)退耕還林工程實(shí)施效果提供依據(jù)。結(jié)果表明:1)土壤CO_2年均排放通量(149.44~204.82 mg/(m~2·h))呈現(xiàn)未間伐農(nóng)田輕度間伐重度間伐的變化趨勢,未間伐較農(nóng)田提高11.6%,輕、重度間伐較農(nóng)田降低11.4%~18.6%,較未間伐顯著降低20.6%~27.0%;2)土壤CH4吸收通量(-0.027~-0.033 mg/(m~2·h))呈現(xiàn)重度間伐未間伐=農(nóng)田輕度間伐變化趨勢,未間伐與農(nóng)田相同,輕度間伐較農(nóng)田降低12.9%,重度間伐較農(nóng)田提高6.5%;3)土壤N_2O排放通量(0.025~0.037 mg/(m~2·h))呈現(xiàn)農(nóng)田重度間伐輕度間伐未間伐的變化趨勢,未間伐較農(nóng)田降低32.4%,輕、重度間伐較農(nóng)田降低24.3%~29.7%;4)溫帶棄耕地造林與間伐經(jīng)營并未改變土壤CO_2、CH_4、N_2O排放通量與氣溫和土壤溫度的相關(guān)性,但改變了3種溫室氣體與土壤濕度的相關(guān)性;5)土壤增溫潛勢(13.89~18.64 t/(hm2·a))呈現(xiàn)未間伐農(nóng)田輕度間伐重度間伐的變化趨勢,未間伐較農(nóng)田提高9.1%,輕、重度間伐較農(nóng)田降低12.1%~18.7%,兩者也較未間伐降低19.4%~25.5%。因此,東北溫帶棄耕地營造落葉松林提高了土壤增溫潛勢,間伐經(jīng)營較大幅度降低了土壤增溫潛勢,故從控制氣候變暖考慮對其采取強(qiáng)度間伐(50%)方式比較適宜。
[Abstract]:The plantations of larch plantations with different thinning intensities on abandoned land in temperate zone were determined by static box and meteorological chromatography. The intensity of light thinning was 25, that of heavy thinning was 50, that of unthinned larch plantations was 25, and that of heavy thinning was 50. Annual greenhouse gas (CO_2,CH_4 and N2O) emission flux and related environmental factors (soil temperature, humidity, nutrient content, etc.) of the corresponding standing farmland and 50 years of forest age and 20 years of thinning. The effects of afforestation and thinning on greenhouse gas emissions from abandoned farmland were revealed in order to provide a basis for quantitative evaluation of the effect of the project. The results showed that: 1) the average annual CO_2 fluxes (149.44 ~ 204.82 mg/) (m ~ (2) h) showed the trend of light thinning and heavy thinning in unthinned farmland. The heavy thinning was lower than that in farmland by 11.4and 18.6b, and 20.6kW was significantly lower than that without thinning by 27.0kW; 2) the absorption flux of CH4 (-0.027 ~ 0.033 mg/) (m ~ (2) h) showed a trend of heavy thinning = light thinning, which was the same as that of farmland, and the decrease of light thinning was 12.9% than that of farmland. Heavy thinning was 6.5% higher than that in farmland. 3) soil N2O fluxes (0.025 ~ 0.037 mg/ (m ~ (2) h) showed the trend of heavy thinning and light thinning without thinning, and the non-thinning was 32.4% lighter than that of farmland. Heavy thinning was 24.3and 29.7m lower than that in farmland. 4) Afforestation and thinning of abandoned land in temperate zone did not change the correlation between soil CO_2,CH_4,N_2O emission flux and air temperature and soil temperature, but changed the correlation between three greenhouse gases and soil moisture. 5) the soil temperature increasing potential (13.89 ~ 18.64 t / (hm2 a) showed the trend of light thinning and heavy thinning in unthinned farmland. The unthinned field increased 9.1%, light, and heavy thinning decreased 12.1% 18.7g than that in farmland. They were also 19.4and 25.5b lower than those without thinning. Therefore, the cultivation of abandoned land in the temperate zone of Northeast China has improved the soil temperature potential, and the thinning management has reduced the soil temperature potential by a large margin. Therefore, it is more appropriate to take the intensity thinning (50%) to control climate warming.
【作者單位】： 東北林業(yè)大學(xué)生態(tài)研究中心;
【基金】：國家自然科學(xué)基金重點(diǎn)項(xiàng)目(41430639)
【分類號】：S714

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本文編號：2356217