Aim European and North american studies have suggested that nitrogen(N)depositions reduce plant diversity and increase primary pro-ductivity due to changes in plant traits.To predict the vegetation response to future ...Aim European and North american studies have suggested that nitrogen(N)depositions reduce plant diversity and increase primary pro-ductivity due to changes in plant traits.To predict the vegetation response to future global change,experimental validations from other regions are widely needed.We assessed the effects of N treat-ment by urea fertilization on the diversity and biomass of the her-baceous plant traits(HPTs)in a dry tropical environment of India.Methods Diversity and biomass of different HPTs were determined on the basis of data collected in year 2010,from 135,1 m×1 m plots dis-tributed over 15 locations.The plots were treated with urea fertilizer in different doses(Control,60 kgNha−1 yr−1 and 120 kg N ha−1yr−1)since 1st January 2007.The plots were ordinated and data were subjected to appropriate statistical analyses.Important Findings Correspondence analysis(Ca)suggested uniqueness of species composition due to N amendment.species number and biomass of the trait categories varied due to N fertilization and traits.all studied trait categories(except N-fixers)yielded maximum mean species number at moderate level of N fertilization.Different levels of N fer-tilization exhibited different species diversity-primary productivity(D-P)relationships.Further,study showed reduction in plant diver-sity due to increase in biomass at high rates of N addition.Conclusions Tall,erect,non N-fixers,annuals,grasses HPTs were favoured by N enrichment.N dose above 60 kg enhanced the biomass of fast grow-ing,erect,annuals,non N-fixers,nitrophilic HPTs.The changes in traits with N addition,especially the increase in annuals and grasses and decrease in typically N-rich N-fixers,have implications for sus-tainable cattle production.展开更多
文摘Aim European and North american studies have suggested that nitrogen(N)depositions reduce plant diversity and increase primary pro-ductivity due to changes in plant traits.To predict the vegetation response to future global change,experimental validations from other regions are widely needed.We assessed the effects of N treat-ment by urea fertilization on the diversity and biomass of the her-baceous plant traits(HPTs)in a dry tropical environment of India.Methods Diversity and biomass of different HPTs were determined on the basis of data collected in year 2010,from 135,1 m×1 m plots dis-tributed over 15 locations.The plots were treated with urea fertilizer in different doses(Control,60 kgNha−1 yr−1 and 120 kg N ha−1yr−1)since 1st January 2007.The plots were ordinated and data were subjected to appropriate statistical analyses.Important Findings Correspondence analysis(Ca)suggested uniqueness of species composition due to N amendment.species number and biomass of the trait categories varied due to N fertilization and traits.all studied trait categories(except N-fixers)yielded maximum mean species number at moderate level of N fertilization.Different levels of N fer-tilization exhibited different species diversity-primary productivity(D-P)relationships.Further,study showed reduction in plant diver-sity due to increase in biomass at high rates of N addition.Conclusions Tall,erect,non N-fixers,annuals,grasses HPTs were favoured by N enrichment.N dose above 60 kg enhanced the biomass of fast grow-ing,erect,annuals,non N-fixers,nitrophilic HPTs.The changes in traits with N addition,especially the increase in annuals and grasses and decrease in typically N-rich N-fixers,have implications for sus-tainable cattle production.
