土地利用方式对豫西丘陵区土壤团聚体稳定性及其化学计量特征的影响

Effects of Land Use Type on Soil Aggregate Stability and its Stoichiometric Characteristics in Hilly Region of West Henan Province

为探究不同土地利用方式对土壤团聚体组成和碳、氮、磷化学计量特征的影响,以豫西丘陵区相同冲积母质土壤为研究对象,对果园、林地、草地和农田等4种土地利用方式的土壤团聚体稳定性、碳含量、氮含量、磷含量及化学计量特征进行了测定分析。结果表明:4种土地利用方式土壤均表现出以0.25~2 mm粒级为优势团聚体分布的特征,以农田土壤最高,质量分数为58.49%~66.11%,土壤团聚体稳定性农田>林地>草地和果园。全碳含量(以质量比表示)随团聚体粒级的下降呈现减少趋势,果园在4个粒级上的全碳含量均显著地高于其他3种土地利用方式,在<2 mm的2个粒级上4种土地利用方式的全碳含量均表现为果园>农田>林地>草地。果园C/N和C/P均显著地高于林地、草地和农田,林地在<2 mm的3个土壤团聚体粒级上的C/N均显著低于草地和农田,但在<2 mm土壤团聚体粒级上的C/P和N/P均显著高于草地。土地利用方式对土壤团聚体稳定性和化学计量特征有显著影响。豫西丘陵区的农田团聚体稳定度最高,果园显示出高的有机输入特征,林地主要受磷限制,草地主要受氮限制。

To explore the effect of different land use types on the composition and C,N,P stoichiometric characteristics of soil aggregates,the same parent material of alluvial soil from 4 land use types including orchard,forestland,grassland and farmland in hilly region of west Henan province were determinated and analyzed with the stability,C content,N content,P content and its stoichiometric characteristics of soil aggregates.The results indicat that the size scale of 0.25~2 mm soil aggregate is predominant and the mass fraction ranges from 58.49%to 66.11%in 4 land use types while farmland is the highest,soil aggregates stability shows farmland>forestland>grassland and orchard.The content(expressed in mass ratio)of organic carbon render descending trend along with aggregate size declining.The organic carbon content of orchard is significantly higher than other 3 land use types at 4 aggregate size scales,soil organic carbon contents at 2 aggregates size scales which less than 2 mm show a significant decreasing trend by orchard,farmland,forestland and grassland.C/N and C/P in orchard are significantly higher than forestland,grassland and farmland.C/N at 3 aggregates size scales which less than 2mm in forestland are significantly lower than grassland and farmland while C/P and N/P at aggregates size scales which less than 2mm are significantly higher than grassland.The soil aggregate stability and stoichiometric characteristics are considerably affected by land use type.The aggregate stability in farmland is the highest among 4 land use types,high organic inputting appears in orchard,forestland is restricted by P and grassland is restricted by N.