A scientific article by PhD researcher Mekhrovar Okhonniyozov of the Research Center for Ecology and Environment of Central Asia (Dushanbe), National Academy of Sciences of Tajikistan, in collaboration with researchers from Tajikistan and China, has been published in the international journal “Journal of Arid Land”. The journal is indexed in major international scientific databases and is recognized as a leading publication in the fields of dryland ecology, environmental sciences, and sustainable land management.

The study, entitled “Grassland biomass production and plant species diversity in response to nitrogen and phosphorus addition in central and southwestern Tajikistan”, investigates how nutrient enrichment affects grassland productivity and biodiversity across different ecological zones of Tajikistan. The research was conducted through a five-year field experiment (2018–2022) at four grassland sites located along an elevational gradient in central and southwestern Tajikistan.

The authors examined the effects of different nitrogen (N) and phosphorus (P) fertilizer treatments on aboveground biomass production and plant species diversity. The results demonstrated that nutrient addition significantly increased grassland productivity at all study sites. Compared with untreated control plots, aboveground biomass increased by 20%–80% under moderate nitrogen application and by up to 190%–200% under combined high nitrogen and phosphorus treatments. The strongest productivity response was observed in high-elevation mountain meadows.

At the same time, the study revealed that nutrient enrichment can negatively affect biodiversity. Plant species richness and diversity declined in some grassland ecosystems, particularly under long-term or intensive fertilization. The responses varied among sites, indicating that elevation, climate conditions, and local ecological characteristics play important roles in determining how grassland communities react to nutrient inputs.

Using statistical modeling, including Structural Equation Modeling (SEM), the researchers demonstrated that nutrient addition directly promotes biomass production while generally suppressing plant species diversity. The study also highlighted the important role of precipitation and temperature in regulating grassland ecosystem responses to fertilization and climate change.

The findings provide the long-term experimental evidence on the effects of nitrogen and phosphorus enrichment on grasslands in Tajikistan. The results are important for sustainable pasture management, biodiversity conservation, and climate change adaptation in mountain and semi-arid ecosystems. The authors emphasize that moderate and site-specific fertilizer application strategies are necessary to increase forage production while maintaining ecological stability and biodiversity.

The article was authored by Mekhrovar Okhonniyozov, Lianlian Fan, Xuexi Ma, Sino Yusupov, Hikmat Hisoriev, Abdullo Madaminov, Fakher Abbas, Ye Tao, and Yaoming Li.

https://www.sciencedirect.com/science/article/pii/S1674676726000757?via%3Dihub

https://www.researchgate.net/publication/404939755_Grassland_biomass_production_and_plant_species_diversity_in_response_to_nitrogen_and_phosphorus_addition_in_central_and_southwestern_Tajikistan