摘要
依托青藏高原东北隅高寒矮嵩草草甸的5a放牧强度(禁牧、轻度放牧、中度放牧、重度放牧)试验平台,2016年在植物生长季的6-9月,基于静态暗箱-气相色谱法,测定N2O的释放特征及相应的环境、生物因子,探讨放牧强度对高寒草甸N2O释放特征的影响及其内在环境生物驱动机制。结果表明:环境、生物因子中仅表层土壤容积含水量、土壤容重及土壤有机碳含量对放牧强度响应显著(P<0.05)。高寒草甸N2O释放的季节特征表现出生长季的早期和晚期相对较高的"U"型趋势。禁牧样地N2O释放速率最小,极显著(P<0.01)低于其它3个放牧样地。高寒草甸N2O释放强度与放牧强度间表现出正相关趋势(R=0.49,P<0.01)。相关分析表明,表层土壤温度是高寒草甸N2O释放速率的主要影响因子,但放牧强度改变了土壤温度的影响程度。中短期放牧管理改变了高寒草甸植被生长季N2O释放速率,但未改变其释放的季节特征。禁牧管理提高了土壤温度,进而显著降低植被生长季N2O释放强度。
Based on the experimental platform of 5 years grazing density including fencing(CK), light grazing(LG), moderate grazing(MG) and heavy grazing(HG) over the alpine Kobresia meadow on the northeastern Qinghai-Tibet Plateau, the characteristics of N_2O effluxes and its main environmental factors of different grazing density were studied by static closed chamber-gas chromatography method from June to September in 2016.The results showed that only the topsoil water content, topsoil bulk density and topsoil organic carbon content responded significantly(P<0.05) to the grazing density. The seasonal patterns of N_2O effluxes showed the "U" shape with relatively higher rate during early and late stage of growing season in alpine meadow. The N_2O effluxes in fencing treatments was clearly(P<0.01) lower than that of other three grazing gradients. There was a little positive trend between N_2O effluxes and grazing density. The surface soil temperature played a predominated role in the seasonal variations of the N_2O effluxes in alpine meadow and its magnitude was influenced by grazing density. The results suggested that only the magnitude, not the direction, of N_2O effluxes was significantly influenced by the medium(short)-term grazing management during growing season. The fencing management could significantly reduce the N_2O emission caused by improving the soil temperature.
出处
《中国农业气象》
CSCD
北大核心
2018年第1期27-33,共7页
Chinese Journal of Agrometeorology
基金
青海省国际科技合作项目(2015-HZ-804)
国家自然科学基金项目(31300385
31270523)
关键词
氧化亚氮
放牧强度
高寒草甸
静态暗箱-气相色谱法
Spearman秩相关
Nitrous Oxide
Grazing density
Alpine meadow
Static closed chamber-gas chromatography method
Spearman's rank correlation coefficient
