云雾山不同恢复方式下草地植物与土壤的化学计量学特征

Ecological stoichiometric characteristics of plants and soil in grassland under different resto-ration types in Yunwu Mountain,China

研究云雾山天然草地、灌草地、禁牧地、撂荒地4种恢复方式下草地各植物组分(植物地上部分、枯落物、根系)与土壤C、N、P化学计量特征及其相互关系.结果表明:土壤与植物地上部分和根系的化学计量学特征显著相关,并且植物地上部分与根系之间P的联系比N紧密,土壤与植物地上部分和根系之间N的联系比P紧密,而土壤与枯落物、根系与枯落物的化学计量学特征相关性不显著.不同恢复方式间植物地上部分和根系总体的C、N储量无显著差异,P储量差异显著且以撂荒地最大(0.49 g·m^(-2))禁牧地最小(0.29 g·m^(-2)).禁牧年限对植物和土壤的化学计量学特征影响较小;耕地撂荒恢复12年后土壤C、N(分别为9.98和1.07g·kg^(-1))仍显著低于天然草地(分别为14.27和1.55 g·kg^(-1)),两者植物化学计量特征的差异由撂荒地各植物组分P浓度高引起;由于根系生物量的稀释作用,天然草地根系N、P浓度最低(分别为6.25和0.57 g·kg^(-1));灌草地地上部分N、P浓度偏低(分别为12.77和0.98g·kg^(-1)},但根系N、P浓度偏高(分别为9.30和0.77 g·kg^(-1)).物种组成是影响植物生态化学计量学特征变化的主要因素,不同恢复方式间群落相似度高则整体化学计量特征差异小.

Carbon （C）, nitrogen （N） and phosphorus （P） stoichiometry from the aboveground parts of plants, roots, plant litter and soils, as well as their relationships were studied in grassland under four distinct types of vegetation recovery including natural grassland, grassland with shrubs, grassland after grazing exclusion, and abandoned cropland in Yunwu Mountain, China. The results showed that there was significant correlation among the ecological stoichiometric characteristics of soils with the aboveground parts and roots. The relation between the aboveground parts and roots was closer in P concentration than in N concentration. The linkage of plants and soils was closer in N concentration than in P concentration. The ecological stoichiometric relationships between soils and litter as well as between roots and litter were weak. There was no significant difference between the aboveground parts and roots in total C and N storages among four distinct recovery methods. However, the P storage differed greatly among the four recovery types with the maximum of 0.49 g · m-2 in the abandoned cropland and the minimum value of 0.29 g · m-2 in the grassland after grazing ex- clusion. Grazing prohibition duration had minor effects on ecological stoichiometrie characteristics. The 12-year-abandoned cropland had lower soil organic C and total N concentration （9.98 and 1.07 g · kg-1 , respectively） compared with natural grasslands （ 14.27 and 1.55 g · kg-1 , respectively）, and this difference of ecological stoichiometric characteristics was caused by the high P concentration in abandoned cropland. The roots N and P concentrations were the lowest in natural grassland with 6.25 and 0.57 g· kg-1 , respectively, due to the greatest amount of root biomass. The N and P concentrations in the grassland with shrubs were relatively lower in the aboveground parts （12.77 and 0.98 g · kg-1 ,respectively） while relatively higher in roots （9.30 and 0.77 g · kg-1, respectively）. Overall, the plant composition was the key factor that influenced the ecological stoichiometric characteristics of plant communities. The distinctions of the ecological stoichiometric characteristics among different restoration types decreased with the increasing Sorensen index.