造林与间伐对东北温带弃耕地土壤温室气体排放的长期影响

发布时间：2018-11-25 13:10

【摘要】：采用静态箱-气象色谱法,测定不同间伐强度温带弃耕地落叶松人工林(未间伐为对照、轻度间伐强度为25%、重度间伐强度为50%,林龄50年及间伐已20年)及相应立地上农田的土壤温室气体(CO_2、CH_4和N_2O)排放年通量与相关环境因子(土壤温度、湿度及养分含量等),揭示造林与间伐对弃耕地土壤温室气体排放的影响规律,以便为定量评价退耕还林工程实施效果提供依据。结果表明:1)土壤CO_2年均排放通量(149.44~204.82 mg/(m~2·h))呈现未间伐农田轻度间伐重度间伐的变化趋势,未间伐较农田提高11.6%,轻、重度间伐较农田降低11.4%~18.6%,较未间伐显著降低20.6%~27.0%;2)土壤CH4吸收通量(-0.027~-0.033 mg/(m~2·h))呈现重度间伐未间伐=农田轻度间伐变化趋势,未间伐与农田相同,轻度间伐较农田降低12.9%,重度间伐较农田提高6.5%;3)土壤N_2O排放通量(0.025~0.037 mg/(m~2·h))呈现农田重度间伐轻度间伐未间伐的变化趋势,未间伐较农田降低32.4%,轻、重度间伐较农田降低24.3%~29.7%;4)温带弃耕地造林与间伐经营并未改变土壤CO_2、CH_4、N_2O排放通量与气温和土壤温度的相关性,但改变了3种温室气体与土壤湿度的相关性;5)土壤增温潜势(13.89~18.64 t/(hm2·a))呈现未间伐农田轻度间伐重度间伐的变化趋势,未间伐较农田提高9.1%,轻、重度间伐较农田降低12.1%~18.7%,两者也较未间伐降低19.4%~25.5%。因此,东北温带弃耕地营造落叶松林提高了土壤增温潜势,间伐经营较大幅度降低了土壤增温潜势,故从控制气候变暖考虑对其采取强度间伐(50%)方式比较适宜。
[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.
【作者单位】：东北林业大学生态研究中心;
【基金】：国家自然科学基金重点项目(41430639)
【分类号】：S714

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