Aims Grassland degradation has become a common problem worldwide.Several studies have analyzed the effects of nitrogen(N)addition on plant growth in grasslands,but few have considered its effects on plant growth in de...Aims Grassland degradation has become a common problem worldwide.Several studies have analyzed the effects of nitrogen(N)addition on plant growth in grasslands,but few have considered its effects on plant growth in degraded grasslands.The aim of this study was to evaluate the effects of N addition on plant growth in grasslands with different levels of degradation in Inner Mongolia,China.Methods A 2-year field experiment was conducted to evaluate plant growth response to N addition in degraded grasslands on the Inner Mongolian Steppe.Grasslands with four levels of degradation were selected for N-addition treatments(0,10,20,30,40,50 g N m−2 year−1).Important Findings Aboveground biomass was increased by N fertilization in degraded grasslands,and N addition was significantly related to increased biomass in grasslands with severe degradation.However,N fertilization did not significantly affect belowground biomass.The effects of N addition on foliar nutrient concentrations in the same species differed among grasslands with different degradation lev-els.There was an inconsistent response to N addition between Sanguisorba officinalis and Vicia sepium in non-degraded grassland.There was a significant positive correlation between foliar N content and aboveground biomass in grasslands with different levels of deg-radation.Our results indicate that the effects of N addition on plant growth in grasslands differ according to the severity of degradation.We conclude that N fertilization may be an effective management technique for degraded grasslands in this area and may improve for-age productivity in the short term.展开更多
基金This research was supported by the Projects of the National Natural Science Foundation of China(Nos.31630009 and 31321061)National key research and development program(No.2016YFC0500701)+1 种基金National Basic Research Program of China(No.2013CB956303)Research Fund of State Key Laboratory of Soil and Sustainable Agriculture,Nanjing Institute of Soil Science,Chinese Academy of Science(Y412201439).
文摘Aims Grassland degradation has become a common problem worldwide.Several studies have analyzed the effects of nitrogen(N)addition on plant growth in grasslands,but few have considered its effects on plant growth in degraded grasslands.The aim of this study was to evaluate the effects of N addition on plant growth in grasslands with different levels of degradation in Inner Mongolia,China.Methods A 2-year field experiment was conducted to evaluate plant growth response to N addition in degraded grasslands on the Inner Mongolian Steppe.Grasslands with four levels of degradation were selected for N-addition treatments(0,10,20,30,40,50 g N m−2 year−1).Important Findings Aboveground biomass was increased by N fertilization in degraded grasslands,and N addition was significantly related to increased biomass in grasslands with severe degradation.However,N fertilization did not significantly affect belowground biomass.The effects of N addition on foliar nutrient concentrations in the same species differed among grasslands with different degradation lev-els.There was an inconsistent response to N addition between Sanguisorba officinalis and Vicia sepium in non-degraded grassland.There was a significant positive correlation between foliar N content and aboveground biomass in grasslands with different levels of deg-radation.Our results indicate that the effects of N addition on plant growth in grasslands differ according to the severity of degradation.We conclude that N fertilization may be an effective management technique for degraded grasslands in this area and may improve for-age productivity in the short term.
