Abstract: We investigated the effects of different agronomy treatments on the oat cultivation grassland soil carbon and nitrogen stock dynamic and the carbon/nitrogen ratio,to provide a theoretical basis for the study of carbon and nitrogen stock and ecological evaluation of oat cultivation grassland in the alpine region of Qinghai-Tibet plateau. We carried out orthogonality test[L₁₆(4⁵)] to analyse the carbon and nitrogen stock dynamic and C/N ratio among the growth period of different soil layers. As the results shown,both of the carbon and nitrogen stock at the 0~50cm and 0~30cm soil layers increased and decreased during the growth period and got the peak value at the heading period;the carbon and nitrogen stock in the 30~50 cm increased during the growth period and got the peak value at milk period. After the harvest,the soil carbon and nitrogen stock were higher than the growth period. Fertilizer played the main role in the carbon and nitrogen stock compared with the other agronomy measures. The C/N ratio was higher under the A. sativa cv. Qinghai,organic fertilizer addition and monoculture oat. The C/N ratio of 0~50cm soil layer increased beginning,and decreased at the middle growth period,and increased under of the growth period,got the peak value at the heading and milk period (15.46 and 15.49,respectively). The C/N ratio increased in the surface soil layer but decreased at the deep soil layers,got the peak value at 20~30 cm soil layer (19.14).

Key words: Alpine area, Oats cultivation grassland, Growth period, Soil carbon and nitrogen stock, C/N

摘要： 为研究燕麦（Avena sativa L.）品种、施肥和箭筈豌豆（Vicia sativa L.）混播比例对燕麦人工草地土壤碳、氮储量及碳氮比的影响，为青藏高原高寒地区燕麦人工草地固碳、固氮能力研究和生态评价提供理论依据，本试验采用三因素四水平正交试验设计[L₁₆（4⁵）]研究了不同生育期土壤碳、氮储量和碳氮比变化特征。结果表明，随着生育期的推进，0~50 cm和0~30 cm土层土壤碳、氮储量均呈"先增后降"的变化规律，抽穗期最高；30~50 cm土层呈持续增加的变化规律，乳熟期最高；牧草收获后一个月的土壤碳、氮储量均显著高于牧草生长季。施肥对0~50 cm土层碳氮比（C/N）的影响显著。各土层平均C/N分别以青海甜燕麦、施有机肥和燕麦单播下最高。0~50 cm土层C/N在抽穗期和乳熟期最高，分别为15.46和15.49；各土层C/N随土层的加深呈"先增后降"变化，以20~30 cm土层的C/N最高，达19.14。

关键词: 高寒区, 燕麦人工草地, 生育期, 土壤碳氮储量, 碳氮比