川西北高寒沙地不同生态治理模式下土壤碳氮磷储量及生态化学计量特征

选取单植牧草、单植灌木、灌草间作、灌药间作4种生态模式治理5年后的川西北高寒沙地为研究对象,以未治理裸沙地为对照,分析了土壤碳氮磷含量及生态化学计量比特征。结果表明: 生态治理能显著提升土壤有机碳(SOC)、总氮(TN)、总磷(TP)含量和储量以及C/N、C/P、N/P,其中灌草间作提升效果最显著,其0～10和10～20 cm土层的SOC、TN含量均显著高于其他模式,且0～40 cm土层SOC储量分别比单植牧草、单植灌木、灌草间作、对照高13.4%、15.6%、17.1%、43.2%。0～10和10～20 cm土层土壤碱解氮、速效磷、速效钾、含水量与SOC、TN和TP含量呈显著正相关,土壤容重则与SOC、TN和TP含量呈显著负相关;土壤碱解氮、速效磷、速效钾和含水量与C/N、C/P在10～20 cm土层呈显著正相关。川西北高寒沙地土壤碳氮磷及其化学计量比受生态治理措施和土层深度的影响,本研究条件下灌草间作模式最有利于改善沙地土壤环境质量。

Storage and ecological stoichiometry of soil carbon,nitrogen, and phosphorus under diffe-rent ecological restoration patterns in the alpine desertified grassland of northwestern Sichuan,China

We analyzed carbon (C), nitrogen (N), and phosphorus (P) contents and their stoichiometric characteristics of sandy soil in four restoration patterns after 5 years restoration in the northwest Sichuan, China, including planting grass alone (PG), planting shrub alone (PS), shrub-grass intercrop (SG), and shrub-herb intercrop (SH). The untreated sand land was set as control (CK). The results showed that soil organic carbon (SOC), total nitrogen (TN), total phosphorus (TP), C/N, C/P, and N/P were increased under different restoration patterns, especially under shrub-grass intercrop (SG). In 0-10 cm and 10-20 cm soil layers, the contents of SOC and TN under SG were significantly higher than that under other patterns. In 0-40 cm soil layer, the SOC storage under SG was higher than that under PG, PS, SH, and CK by 13.4%, 15.6%, 17.1% and 43.2%, respectively. The available N, available P, available K, and water content were positively correlated to SOC, TN, and TP in 0-10 cm and 10-20 cm soil layers. Soil bulk density was negatively correlated to SOC, TN and TP. The alkaline N, available P, available K, and water content were significantly correlated to C/N and C/P in 10-20 cm soil layer. The contents and stoichiometry of soil C, N and P were affected by both ecological restoration measures and soil depth. The shrub-grass intercrop pattern was most beneficial to improve sandy soil environment quality in the study area.