Aims Nutrient resorption is a key plant nutrient conservation strategy,and its response to environmental and management changes is linked to nutrient cycling and production of ecosystems.Defoliation is a major pathway...Aims Nutrient resorption is a key plant nutrient conservation strategy,and its response to environmental and management changes is linked to nutrient cycling and production of ecosystems.Defoliation is a major pathway of mowing affecting plant nutrient resorption and production in grasslands,while the effect of defoliation timing has not been unexplored.The aim of this study was to examine the effect of defoliation timing on plant nutrient resorption and production in a steppe ecosystem.Methods We conducted a field experiment in a semi-arid steppe of Inner Mongolia including four treatments:early defoliation,peak defoliation,late defoliation and non-defoliation.We measured plant nitrogen(N)and phosphorus(P)resorption at species and community levels,and quantified plant N and P fluxes in resorption,litter return and hay output.Plant production in the mowing system was assessed by hay production and quality.Important Findings Peak and late defoliation,but not early defoliation,reduced plant community N and P resorption proficiency;and late defoliation reduced N resorption efficiency but not P resorption efficiency.Peak and late defoliation,but not early defoliation,reduced plant nutrient resorption flux and litter nutrient return flux.Defoliation timing did not alter root nutrient accumulation as nutrient uptake from soil likely compensated the deficit of nutrient resorption.Peak defoliation had the highest hay production and quality,while early defoliation had the lowest.Our results provide new insights into the nutrient cycling in mowing grassland,and imply that the mowing timing can be used as a tool to mediate the balanee between conservation and production of steppes,and the early mowing before plant peak biomass period is recommended for conservation of the steppes while keeping sustainable pastoral production.展开更多
基金supported by the Ministry of Science and Technology of China(2015BAC02B04,2016YFC0500508)the Departmeni of Science and Technology of Inner Mongolia Autonomous Region of China(201503001,2019ZD007)the National Natural Science Foundation of China(32071564).
文摘Aims Nutrient resorption is a key plant nutrient conservation strategy,and its response to environmental and management changes is linked to nutrient cycling and production of ecosystems.Defoliation is a major pathway of mowing affecting plant nutrient resorption and production in grasslands,while the effect of defoliation timing has not been unexplored.The aim of this study was to examine the effect of defoliation timing on plant nutrient resorption and production in a steppe ecosystem.Methods We conducted a field experiment in a semi-arid steppe of Inner Mongolia including four treatments:early defoliation,peak defoliation,late defoliation and non-defoliation.We measured plant nitrogen(N)and phosphorus(P)resorption at species and community levels,and quantified plant N and P fluxes in resorption,litter return and hay output.Plant production in the mowing system was assessed by hay production and quality.Important Findings Peak and late defoliation,but not early defoliation,reduced plant community N and P resorption proficiency;and late defoliation reduced N resorption efficiency but not P resorption efficiency.Peak and late defoliation,but not early defoliation,reduced plant nutrient resorption flux and litter nutrient return flux.Defoliation timing did not alter root nutrient accumulation as nutrient uptake from soil likely compensated the deficit of nutrient resorption.Peak defoliation had the highest hay production and quality,while early defoliation had the lowest.Our results provide new insights into the nutrient cycling in mowing grassland,and imply that the mowing timing can be used as a tool to mediate the balanee between conservation and production of steppes,and the early mowing before plant peak biomass period is recommended for conservation of the steppes while keeping sustainable pastoral production.
基金supported by the National Natural Science Foundation of China(32071564)the Department of Science and Technology of Inner Mongolia Autonomous Region of China(2019ZD007 and 2022LHQN03001)the Open Project of Collaborative Innovation Center for Grassland Ecological Security,Ministry of Education of China.Conflict of interest statement.
