不同类型凋落物对土壤有机碳矿化的影响

Effects of Different Types of Litters on Soil Organic Carbon Mineralization

通过实验室凋落物培养试验,对南京紫金山地区4种典型植被凋落物的分解差异进行了比较研究.结果表明,含凋落物土壤有机碳矿化包含快速分解和缓慢分解2个过程,前者日均分解量大持续时间短,后者与之相反.4种含凋落物土壤在培养初期矿化速率迅速达到最大,大小依次为狗牙根凋落物土壤（CK＋BMD）（23.88±0.62）mg·d^-1、马尾松凋落物土壤（CK＋PML）（17.93±0.99）mg·d^-1、麻栎凋落物土壤（CK＋QAC）（15.39±0.16）mg·d^-1和青冈栎凋落物土壤（CK＋CGO）（7.26±0.34）mg·d^-1,相互间差异均达到显著水平（p〈0.05）,此顺序与凋落物初始化学元素组成关系不明显.培养3个月,含凋落物土壤有机碳累积矿化量分别为：（CK＋BMD）（338.21±6.99）mg、（CK＋QAC）（323.48±13.68）mg、（CK＋PML）（278.34±13.91）mg和（CK＋CGO）（245.21±4.58）mg.从凋落物自身分解率分析,4种凋落物在培养期间共释放了198.17-297.18 mg的CO2-C,占到加入凋落物中有机碳总量的20.29%-31.70%.对有机碳矿化速率和累积矿化量变化趋势分析后发现,乘幂曲线模型能很好地描述其变化,且相关性较好.

Using litter incubation experiment in laboratory, decomposition discrepancies of four typical litters from Zijin Mountain were analyzed. The results show that organic carbon mineralization rates of soil with litters all involve fast and slow decomposition stages, and the differences are that the former has shorter duration, more daily decomposition quantity while the latter is opposite. Organic carbon mineralization rates of soil with litters rapidly reached maximum in the early days of incubation, and the order is soil with Cynodon dactylon litter （ CK ＋ BMD） （23.88±0.62） mg·d^-1 ,soil with Pinus massoniana litter （CK ＋ PML） （ 17.93 ＋ 0.99） mg·d^-1 , soil with Quercus acutissima litter （CK ＋ QAC） （15.39：/：0.16） mg·d^-1 and soil with Cyclobalanopsis glauca litter （CK ＋ CGO） （7.26± 0.34） mg·d^-1 ,and with significant difference between each other （p 〈 0.05）. This order has not significant correlation to litter initial chemical elements. The amount of organic carbon mineralized accumulation within three months incubation is （CK ＋ BMD）（338.21 ± 6.99） rag, （CK ＋ QAC）（323.48 ± 13.68）mg, （CK ＋ PML） （278.34 ± 13.91 ）mg and （ CK ＋ CGO） （ 245.21 ± 4.58 ） mg. 198.17-297.18 mg CO2 - C are released during litter incubation, which occupies 20.29%-31.70% of the total litter organic carbon amounts. Power curve model can describe the trends of organic carbon mineralization rate and mineralized accumulation amount, which has a good correlation with their change.