Establishment of Inventory on Carbon and Nutrient Cycling in Tropical Peatland Ecosystems for Sustainable Agro-production and Environmental Conservation

热带泥炭地是全球陆地表面碳(C)净储量的重要来源，但它也被认为是甲烷的主要排放源。土地资源的开发和泥炭的燃烧增加了泥炭地碳的释放，从而导致全球变暖。为了弄清热带泥炭地农业和火灾对全球变暖的影响程度，从2001年到2003年，测量了森林和农田等不同生态系统以及靠近Plangka Raya的Karampangan区受火灾影响的土地上3种主要温室气体CO2、CH4和N2O的地表排放量。森林焚烧后，天然林GWP下降了32%-42%，99%的GWP来自CO2排放。然而，没有树木能够吸收二氧化碳，因此二氧化碳排放直接进入大气。甲烷是从燃烧的泥炭地排放出来的，而天然林和再生林都吸收了CH4。农业领域的全球变暖潜能值大约是天然林的2倍。农业领域的二氧化碳排放量大约是日本农作物领域的5倍，占全球变暖潜能值的50%-90%。剩余的全球变暖潜势是由N2O排放贡献的。N2O排放量相当大，占施氮量626 kg/hm2的4~23%，这可能是由于高pH和高交换性钙含量促进了泥炭分解和硝化作用的结果。但农田施氮可加速豌豆分解，增加N2O排放，减少CH4吸收。

Tropical peatland is important for net carbon (C) storage in the global land surface, but it is also believed to be a major emission source of CH4.Land resource exploitation and burning of peat increases C release from the peatland, and thus contributes to overall global warming. In order in discern the magnitude of agricultural and fire impacts in tropical peatlands on global warming, ground surface emissions of three major greenhouse gases (GHG), CO2, CH4 and N2O, were measured in various ecosystems including forests and agricultural fields, as well as fire-affected lands in Karampangan zone, near Plangka Raya, from 2001 to 2003.After forest burning, the GWP decreased in 32-42% of the GWP from the natural forest, with 99% of the GWP occurring from CO2 emission. However, no trees could absorb the CO2, so the CO2 emissions went directly to the atmosphere.CH4 was emitted from the burned peatland, while CH4 uptake was observed in both the natural and regenerated forests.The GWP in the agricultural field was approximately 2 times larger than that from the natural forest. CO2 emission in the agricultural field was about 5 times larger than that in Japanese crop fields and accounted for 50-90% of the GWP. The remaining GWP was contributed by N2O emission. The N2O emission was considerably high, accounting for 4-23% of the nitrogen (N) application rate of 626 kg N ha1 yr-1.This is probably due to high peat decomposition and high nitrification enhanced by high pH and high exchangeable Ca content us the agricultural fields.Magnitude of forest fire impact on global warming was much higher than agricultural impact. But nitrogen application in agricultural field, which may accelerate peas decomposition, enhanced N2O emission and deduced CH4 uptake.