Abstract: In order to explore the effects of different precipitation on soil stoichiometric characteristics under Reaumuria soongorica litters in arid desert region,the soil under litter layer of R. soongorica in arid desert region were selected as the research objective in this study. There were three precipitation treatments:the normal precipitation,precipitation increased by 30% and decreased by 30% which were designed and set up in our experiment. The soil organic carbon (SOC),total nitrogen (TN),total phosphorus (TP) content and stoichiometric characteristics during the decomposition period of R. soongorica litter under those different precipitation conditions were measured and analyzed. The results showed that:compared to the normal precipitation,the SOC contents of 0~5 cm soil layer were significantly enhanced after 15 month of litter decomposition under the treatment of precipitation increased by 30%,but the SOC,TN and TP contents were significantly reduced under the precipitation decreased by 30%. The TP content of 5~15 cm soil layer reduced significantly both under the precipitation increased and decreased by 30%. The C:P and N:P ratio in 0~5 cm soil layer were significantly reduced under the precipitation decreased by 30% treatment,but the N:P ratio in 5~15 cm soil layer was enhanced significantly under the both precipitation increased and decreased by 30% treatments. In general,under the precipitation pattern change in the future,the increased precipitation would contribute to the accumulation of soil organic carbon in the soil surface layer under R. soongorica litter layer in arid desert regions,but the decreased precipitation would reduce the soil nutrients and stoichiometric characteristics.

Key words: Reaumuria soongorica litters, Precipitation change, Litter decomposition, Nutrient content, Stoichiometric characteristics

摘要： 为探究降水变化对干旱荒漠区凋落物分解下土壤化学计量特征的影响,本研究以红砂(Reaumuria soongorica)凋落物下的土壤为研究对象,设置了自然降水、降水增加30%和降水减少30%三种降水处理,测定与分析了不同处理下土壤的有机碳(SOC)、全氮(TN)、全磷(TP)含量以及化学计量特征。结果表明:与自然降水相比,红砂凋落物分解15个月后0~5 cm土层下降水增加30%显著提高了SOC含量,而降水减少30%显著降低了SOC,TN和TP含量。对于5~15 cm土层而言,降水增加和减少30%处理均显著降低了TP含量。降水减少30%下0~5 cm土层的C:P和N:P均显著降低;5~15 cm土层下降水增加和减少30%处理对土壤的N:P影响显著。因此,未来降水格局变化下,降水增加有助于干旱荒漠区表层土壤有机碳的积累,对化学计量特征的影响不显著,但降水减少可降低土壤的养分和化学计量特征。

关键词: 红砂凋落物, 降水变化, 凋落物分解, 碳氮磷含量, 化学计量特征