养分添加对科尔沁盐碱化草地植物多样性和地上生物量的影响OA

This study aimed to elucidate the effect of nutrient addition on plant diversity and aboveground biomass in saline-alkali grassland,and to explore the relationship between these two factors.The overall goal of this research was to provide a theoretical foundation and data support for the restoration,reconstruction,and utilization of saline-alkali grassland ecosystems.A field study was conducted in saline-alkali grassland in Horqin.The experiment had a randomized block design,and consisted of a control(no fertilization,CK)and six treatments:nitrogen fertilizer+microbial agent(NG),nitrogen fertilizer+bio-organic fertilizer A(NN),nitrogen fertilizer+bio-organic fertilizer B(NO),compound fertilizer+microbial agent(NPG),compound fertilizer+bio-organic fertilizer A(NPN),and compound fertilizer+bio-organic fertilizer B(NPO).Fertilizer was applied in early June and early August of 2023 and 2024,and a vegetation survey was conducted in mid-August of 2024.The effects of adding different types of nutrients on plant diversity and aboveground biomass in saline-alkali grassland were analyzed.The main results were as follows:1)All of the nutrient addition treatments reduced plant diversity to some degree.Compared with CK,the compound fertilizer treatments(NPG,NPN,and NPO)resulted in significant decreases in the Shannon-Wiener index by 13.55%-25.65%,the Pielou index by 6.45%-14.68%,the Margalef index by 14.19%-30.24%,and Simpson index by 3.69%-14.19%.Compared with CK,the nitrogen treatments(NG,NN,NO)resulted in significant decreases in the Shannon-Wiener index by 3.32%-29.17%,the Pielou index by 4.99%-9.54%,the Margalef index by 19.35%-32.18%,and Simpson index by 4.20%-11.64%.2)Nutrient addition treatments significantly increased the aboveground biomass of the community and the biomass of Poaceae in the saline-alkali grassland in Horqin.The combined application of nitrogen and phosphorus had a stronger promoting effect,particularly the combination of compound fertilizer with bio-organic fertilizer B,which increased the aboveground biomass and Poaceae biomass by 74.76%and 123.64%,respectively,compared with CK(P<0.05).The biomass of two functional groups(legumes and forbs)decreased after nutrient addition,but the changes were not statistically significant.3)After nutrient addition,both the Shannon-Wiener index and the Pielou index showed a significant negative linear correlation with aboveground biomass,whereas the Margalef index and Simpson index exhibited non-significant negative correlations with aboveground biomass.Exogenous nutrient addition significantly increased the aboveground biomass of the plant community in saline-alkali grassland in Horqin,primarily driven by the increase in grass family biomass.However,it reduced plant diversity to varying degrees,resulting in a negative linear relationship between species diversity and aboveground biomass.