红壤区林地浅沟不同植被类型土壤生态化学计量特征

Characteristics of Soil Ecological Stoichiometry of Different Vegetation Types in Ephemeral Gully of Forestland in Red Soil Region

为了探究红壤区林地浅沟植被类型对土壤养分含量及其生态化学计量特征的影响,通过野外调查与室内分析相结合的方法,选取林下植被类型为草地和灌木地的浅沟为研究对象,以裸地浅沟为对照,对其表层(0—10 cm)土壤养分含量及生态化学计量特征进行了研究。结果表明:(1)浅沟土壤养分含量及其生态化学计量特征受植被类型和浅沟部位的共同影响。(2)与裸地浅沟相比,草地和灌木地浅沟的土壤养分含量显著增大(p<0.05),草地土壤的C,N和P含量分别增加了67.7%,51.1%,200.0%,灌木地分别增加了84.6%,127.0%,226.3%;土壤生态化学计量特征则显著减小(除草地的C/N外),C/P和N/P分别减小了50.9%,46.8%和65.2%,51.1%。(3)在浅沟不同部位,泥沙沉积导致沟底土壤养分含量显著大于沟坡和沟缘,但生态化学计量特征没有明显的变化规律。(4)土壤C,N和P含量间呈极显著的正相关关系,N含量是C/N的主要限制因子,P含量是C/P和N/P主要限制因子。红壤区林地浅沟植被恢复后,虽然土壤养分含量显著增大,但整体水平仍然偏低,而N和P是该区植被恢复的限制性因素,在植被恢复过程中适当施用氮肥和磷肥,可加快植被恢复进程。

In order to explore the effects of vegetation types on soil nutrients and ecological stoichiometry in ephemeral gully of forestland in red soil region,combining the method of field investigation and indoor analysis,we analyzed soil nutrients(C,N,P)and ecological stoichiometry of top soil(0—10 cm)for ephemeral gullies with different vegetation types.The results showed that:(1)soil nutrients and ecological stoichiometry of ephemeral gully were greatly affected by vegetation types and topographic positions;(2)compared to the bare ephemeral gullies,soil nutrients of ephemeral gullies with grass and shrub increased significantly,the C,N,and P contents of grassland increased by 67.7%,51.1%,200.0%,respectively,and those of shrub land increased by 84.6%,127.0%,226.3%,respectively,while ecological stoichiometry decreased significantly(except for the C/N of grassland),the C/P and N/P decreased by 50.9%,46.8%and 65.2%,51.1%,respectively;(3)for different topographic positions of ephemeral gully,due to the influence of sediment deposition,soil nutrient contents in groove were significantly greater than those of gully slope and edge,while no obvious regular change was found in ecological stoichiometry;(4)correlation analysis indicated that significant positive correlations were found between C,N,and P contents,and N content was the main limiting factor on C/N,P content was the main limiting factor on C/P and N/P.Although the contents of soil nutrients increased significantly,the overall level was still low in ephemeral gully of forestland in red soil region after vegetation restoration.N and P were the limiting factors on vegetation restoration in this region,and proper application of nitrogen and phosphorus fertilizer is beneficial to accelerating the process of vegetation restoration.