Seasonal grazing alters nutrient resorption and conservation,and affects spring growth of Stipa grandis
Nutrient resorption in autumn is a key mechanism of perennial plants for nutrient conservation and efficient use in grassland.Grazing effects on plant nutrient resorption may alter root nutrient conservation and affect plant growth in the subsequent spring.There are many studies on nutrient resorption and conservation of plants in grazing grassland,but few studies have investigated the effect of grazing on plant growth in subsequent spring.Taking Stipa grandis,a dominant perennial grass in a semi-arid steppe as a model plant,we examined plant nitrogen(N)and phosphorous(P)resorption traits(resorption efficiency,proficiency and flux)and root nutrient conservation traits(root biomass and nutrient pool)in autumn,and plant growth traits(height,biomass and nutrient pool)in the subsequent spring,in an experimental grassland under four grazing season treatments(i.e.grazing in spring,summer or autumn or no grazing).We found that(ⅰ)51％-66％of N and 58％-80％of P in S.grandis shoots were resorbed in autumn,and the resorption flux was the lowest under autumn grazing,and highest under spring grazing.(ⅱ)Root nutrient conservation traits were significantly reduced by summer grazing,slightly decreased by spring grazing,but not affected by autumn grazing.(ⅲ)Plant growth in next spring was the best under early spring grazing and the worst under autumn grazing,which was mainly affected by soil moisture rather than root nutrient storage.Our study provides insights into the process of plant nutrient cycling and a theoretical basis for establishing grazing system for grassland protection and rational utilization.
Tongrui Zhang、Frank Yonghong Li、Lin Wu、Hao Wang、Yanlong Li、Chunjun Shi
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Ministry of Education Key Laboratory of Ecology and Resource Use of the Mongolian Plateau & Inner Mongolia Key Laboratory of Grassland Ecology,School of Ecology and Environment,Inner Mongolia University,Hohhot 010021,China
Joint Innovation Center for Grassland Ecological Security of the Ministry of Education of China,Inner Mongolia University,Hohhot 010031,China
Institute of Grassland Research,Chinese Academy of Agricultural Sciences,Hohhot 010010,China
大针茅(Stipa grandis) 季节性放牧 养分回收 养分保存 土壤水分
国家自然科学基金Department of Science and Technology of Inner Mongolia Autonomous Region of ChinaDepartment of Science and Technology of Inner Mongolia Autonomous Region of ChinaOpen Project of Collaborative Innovation Center for Grassland Ecological Security,Ministry of Education of China
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