Abstract:

Soil respiration, soil temperature, soil moisture and organic matter contents were measured under different fertilizer treatments inPoa pratensis'Qinghai'artificial grassland using a EGM-4 analytical instrument of CO₂/H₂O infrared gas to understand the influences of different fertilizers on the soil respiration of grassland. Results showed that the effects of different fertilizers on soil respiration differed significantly. Soil respiration rate (1.72, 1.53 and 0.69 g CO₂·m^-2·h^-1) was improved in the treatment of decomposed sheep manure, whereas soil respiration rate was reduced in the treatment of Phosham during flowering stage (0.99 g CO₂·m^-2·h^-1), was not affected during maturation stage (1.16 g CO₂·m^-2·h^-1), and was improved during yellow stage (0.72 g CO₂·m^-2·h^-1) comparing with control. There were positive correlations between soil respiration rate and soil temperature, the content of organic matter. And there was a linear correlation between soil respiration rate and the soil moisture of 0~10 cm soil layer. Decomposed sheep manure increased Q₁₀, while Phosham and undecomposed sheep manure had no effect onQ₁₀. Correlation indexes of soil respiration and soil moisture in Phosham and decomposed sheep manure treatments were bigger than that in undecomposed sheep manure treatment. Organic fertilizer reduced the correlation index of soil respiration and organic matter, but Phosham had no effect on the correlation index. Decomposed sheep manure increased the sensibility of soil respiration to soil temperature, and reduced the sensibility of soil respiration to the content of organic matter.

Key words: Poa pratensis‘Qinghai’, Soil respiration, Decomposed sheep manure, Phosham, Undecomposed sheep manure

摘要：

为了解草地生态系统对全球碳素变化的贡献，通过便携CO₂/H₂O红外气体分析仪EGM-4研究腐熟羊粪、磷酸二铵和生羊粪处理下青海草地早熟禾（Po apratensis‘Qinghai’）草地的土壤呼吸速率，并测定草地土壤温度、含水量和有机质含量。结果表明：肥料种类对土壤呼吸的影响差异显著。与各处理对照呼吸速率相比（1.27，0.99和0.42g CO₂·m^-2·h^-1），适量腐熟羊粪表现为促进土壤呼吸（1.72，1.53和0.69g CO₂·m^-2·h^-1），而化肥在盛花期时抑制土壤呼吸（0.99g CO₂·m^-2·h^-1），成熟期时对土壤呼吸无影响（1.16g CO₂·m^-2·h^-1），枯黄期则促进土壤呼吸（0.72g CO₂·m^-2·h^-1）。土壤呼吸与土壤温度、有机质含量呈指数正相关，与0~10cm土壤含水量呈线性关系。腐熟羊粪处理提高了Q₁₀，而磷酸二铵和生羊粪对Q₁₀无影响；磷酸二铵和腐熟羊粪处理的土壤呼吸与土壤含水量相关系数比生羊粪的高。有机肥降低了土壤呼吸与土壤有机质的相关系数，而磷酸二铵对其无影响。腐熟羊粪可以提高土壤对土温的敏感性而降低土壤呼吸对土壤有机质含量的敏感性。

关键词: 青海草地早熟禾, 土壤呼吸, 腐熟羊粪, 磷酸二铵, 生羊粪