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凋落物矿化分解是维持生态系统养分循环的关键过程,也是陆地生态系统C向大气释放的主要动力,因此影响和控制生态系统凋落物矿化分解的主要因素一直备受关注。土地沙漠化是科尔沁沙地最严重的环境问题,并且导致土壤粗质化和贫瘠化,凋落物输入和矿化分解对于改善该地区土壤质地和养分状况至关重要。通过室内培养的方法,对科尔沁沙质草地27种主要植物叶凋落物矿化分解及其与凋落物C含量、N含量、木质素含量、C/N、木质素/N、极易分解有机物含量(LOMⅠ)、中易分解有机物含量(LOMⅡ)及难分解有机物含量(RP)等指标关系进行研究。结果表明:科尔沁沙地27种植物叶凋落物质量存在较大差异(P<0.001),相应的27种植物叶凋落物培养样品矿化有机碳总量和干物质损失量存在显著差异(P<0.001),分别在9.0mg C·g~(-1)干土至12.7mg C·g~(-1)干土和14.7%至40.4%之间变化。添加凋落物后培养样品的CO2释放总量显著大于对照(不添加凋落物),说明土壤中添加凋落物后,培养样品的有机碳矿化速率明显增大。27种植物叶凋落物矿化有机碳总量以及损失干物质总量与凋落物的N含量、C/N、木质素/N、LOMⅠ、LOMⅡ和RP等指标存在显著的相关性,叶凋落物的矿化分解主要受LOMⅠ和木质素/N的影响。
Mineralization of litter is the key process to maintain ecosystem nutrient cycle and is also the main driving force for the release of terrestrial ecosystem C to the atmosphere. Therefore, the main factors affecting and controlling the mineralization and decomposition of litter in ecosystems have drawn much attention. Land desertification is the most serious environmental problem in Horqin Sandy Land and leads to the thickening and impoverishment of soils. The litterfall input and mineralization decomposition are crucial to improve the soil texture and nutrient status of the area. Through indoor cultivation, the effects of mineralization and decomposition on the leaf litter mineralization and its relationship with C, N, Lignin, C / N, lignin / N, organic matter content of easily decomposed in Horqin sandy grassland LOMⅠ, LOMⅡ, and refractory organic matter content (RP) were studied. The results showed that the leaf litter quality of 27 species of plants in Horqin sandy land was significantly different (P <0.001), and there was a significant difference in the total amount of mineralized organic carbon and dry matter loss of the 27 kinds of plant leaf litter culture samples (P < 0.001), respectively, from 9.0mg C · g -1 dry soil to 12.7mg C · g -1 dry soil and from 14.7% to 40.4%. After adding litter, the total amount of CO2 released from the cultured samples was significantly higher than that of the control (no litter added), indicating that the organic carbon mineralization rate of the cultured samples increased obviously after adding litter in the soil. The total amount of mineralized organic carbon and the total amount of dry matter lost by leaf litter in 27 species of plants were significantly correlated with N content, C / N, lignin / N, LOMⅠ, LOMⅡ and RP of litter, The mineralization is mainly affected by LOMI and lignin / N.