摘要
为明确植物的用水策略及适应性机制,以内蒙古四子王旗短花针茅荒漠草原为研究对象,设置对照(CK)、轻度放牧(LG)、中度放牧(MG)和重度放牧(HG)4个放牧梯度,其载畜率分别为每1 hm^(2)每年0、0.93、1.82和2.71个羊单位的放牧强度,调查建群种短花针茅的高度、盖度、密度、地上生物量以及土壤的理化性状,并且采用稳定碳同位素法和红外光合仪法对短花针茅水分利用效率进行了测定,旨在阐明短花针茅水分利用效率在不同放牧强度下的响应规律及其影响因素。结果显示:(1)放牧对短花针茅盖度、密度以及地上生物量的影响显著;随着载畜率的增大,有利于短花针茅的扩散使其分布面积增加,且在中度放牧条件下尤为明显。(2)随着放牧强度的增加,土壤水分含量较对照显著提高,土壤全氮含量呈先增加后减少的变化趋势,土壤速效钾呈现降低的变化趋势,而对土壤全碳含量和pH无显著影响,说明适度放牧能够提高土壤水分含量、促进土壤氮含量的积累,但放牧会导致土壤速效钾减少。(3)随着放牧强度的增大,短花针茅长期水分利用效率(WUE l)呈现“V”形变化趋势,而瞬时水分利用效率(WUE t)与内在水分利用效率(WUE i)总体呈降低的变化趋势。(4)相关分析显示,放牧强度与短花针茅密度、地上生物量呈显著正相关关系,土壤全氮含量与有机碳、pH、WUE i呈显著正相关关系,WUE t与WUE i呈显著正相关关系;短花针茅内在水分利用效率与土壤有机碳含量密切相关。研究表明,重度放牧导致短花针茅株丛破碎化,增加了种群的扩散面积,是短花针茅长期水分利用效率提高的直接原因;短花针茅瞬时水分利用效率随放牧强度的增加而降低可能是由其内在水分利用效率降低引起的。
In order to clarify the water use strategy and adaptive mechanism of plants,this study took Stipa breviflora desert steppe of Siziwang Banner,Inner Mongolia as the research object,and set four grazing gradients:control(CK),light grazing(LG),moderate grazing(MG)and heavy grazing(HG).The stocking rates were 0,0.93,1.82 and 2.71 sheep units per hectare per year,respectively.The height,coverage,density,aboveground biomass and soil physicochemical properties of the established species S.breviflora were investigated,and the water use efficiency of S.breviflora was measured by stable carbon isotope method and infrared photophotoapparatus method.The objective was to elucidate the response of water use efficiency of S.breviflora under different grazing intensities and its influencing factors.The results showed that:(1)Grazing had significant effects on coverage,density and aboveground biomass of S.breviflora.With the increase of stocking rate,S.breviflora spread and its distribution area increased,especially under moderate grazing condition.(2)With the increase of grazing intensity,soil moisture content increased significantly compared with the control,soil total nitrogen content increased first and then decreased,soil available potassium showed a trend of decreasing,but had no significant effect on soil total carbon content and pH,indicating that moderate grazing could increase soil moisture content and promote the accumulation of soil nitrogen content,but grazing would lead to the decrease of soil available potassium.(3)With the increase of grazing intensity,long-term water use efficiency(WUE l)showed a V-shaped trend,while instantaneous water use efficiency(WUE t)and intrinsic water use efficiency(WUE i)showed a decreasing trend.(4)Correlation analysis showed that grazing intensity was significantly positively correlated with S.breviflora density and aboveground biomass,soil total nitrogen content was significantly positively correlated with organic carbon,pH and WUE i,and WUE t and WUE i were significantly positively
作者
赵敏
吕世杰
殷国梅
刘思博
孟卫军
韩国栋
ZHAO Min;L Shijie;YIN Guomei;LIU Sibo;MENG Weijun;HAN Guodong(College of Grassland and Resource Environment,Inner Mongolia Agricultural University,Hohhot 010018,China;Inner Mongolia Academy of Agriculture and Animal Husbandry Sciences,Hohhot 010031,China;Comprehensive Security Center of Ordos Bureau of Agriculture and Animal Husbandry,Ordos,Inner Mongolia 017010,China)
出处
《西北植物学报》
CAS
CSCD
北大核心
2023年第6期968-978,共11页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金项目(31560140,31260124)
国家牧草产业技术体系项目(CARS-34)
教育部重点实验室滚动支持项目(IRT_17R59)
中国科学院战略性先导科技专项(A类)(XDA26020103)
内蒙古自治区重大科技专项(2019ZD003)。
关键词
放牧强度
建群种
水分利用效率
植物密度
土壤有机碳
土壤全氮
grazing intensity
establishment species
water use efficiency
plant density
soil organic carbon
soil total nitrogen
