New research from regions such as the Tibetan Plateau and Inner Mongolia highlights that grassland ecosystems experience sudden and often irreversible changes when nitrogen fertilization exceeds critical threshold levels. While nitrogen is essential for plant growth, scientists have identified specific saturation points—ranging from 50 to over 1,300 kg N·ha⁻¹·year⁻¹ depending on grassland type and rainfall—beyond which species diversity sharply declines and invasive species take hold. This disrupts soil nutrient balance and microbial communities, impairing vital ecosystem functions like carbon storage and nutrient cycling.
These ecological disruptions pose significant risks to biodiversity and the climate regulation services grasslands provide globally. Covering nearly 40% of the Earth’s land surface, grasslands act as major carbon sinks. Excess nitrogen not only damages plant communities but can also runoff into water bodies, causing eutrophication and aquatic life loss. The findings underscore the urgent need for sustainable nitrogen management practices to protect ecosystem health, support agriculture, and maintain environmental stability. More