论文部分内容阅读
耕作措施由于其对于农田温室气体排放的影响而备受关注。明确土壤团聚体结合碳的矿化过程有助于探讨耕作对于土壤碳库动态变化的影响机理。本研究测定了火山灰土耕作与免耕处理不同粒径土壤团聚体的全碳量和碳矿化速率。免耕与耕作处理下的小粒径团聚体(<0.25 mm)的全碳含量皆高于大粒径团聚体(>0.25 mm),因为火山灰土的小粒径团聚体含有较高比例的细壤粒和粘粒,而细壤粒和粘粒能够吸附较多的有机物质。免耕与耕作处理的碳矿化速率和全碳量呈显著相关(R~2=0.6552,P=0.002),证明土壤团聚体结合碳的矿化速率受粒径大小的影响。免耕处理可以改善火山灰土的土壤结构。耕作能够增加碳矿化率较高的小粒径团聚体数量,从而增加了耕作处理土壤的碳流失。与团聚体粒径不同,耕作处理对于同一粒径土壤团聚体结合碳矿化速率没有显著影响。
Farming practices have drawn much attention due to their impact on farmland greenhouse gas emissions. It is helpful to clarify the mechanism of tillage on the dynamic changes of soil carbon pool by clarifying the mineralization process of soil aggregates combined with carbon. In this study, the total carbon content and carbon mineralization rate of aggregates of different size of volcanic ash and no-tillage were measured. The total carbon content of small size aggregates (<0.25 mm) under both no-till and tillage treatments was higher than that of large size aggregates (> 0.25 mm) because the small size aggregates of volcanic ash contained a higher proportion of fine Soil and clay particles, and fine clay particles and clay can adsorb more organic matter. There was a significant correlation between carbon mineralization rate and total carbon in no-till and tillage treatments (R ~ 2 = 0.6552, P = 0.002), indicating that the rate of mineralization of soil aggregates bound to carbon is affected by the size of the grain. No-till treatment can improve the soil structure of volcanic ash soil. Farming increased the number of small-sized aggregates with higher carbon mineralization, thereby increasing the carbon loss from tillage treatments. Different from the aggregate size, tillage treatment had no significant effect on the rate of carbon mineralization associated with the same particle size of soil aggregates.