FERTILIZER ADDITION INDUCES A CASCADE OF PLANT COMMUNITY RESPONSES IN A MEADOW.

Fertilizer addition can improve soil nutrients in degraded grasslands, change plant community composition, and promote community productivity. An experiment was established in 2014 near Hulunbuir Grassland Ecosystem National Field Observation Station at Hulunbuir in Inner Mongolia, China, using L14 (3⁴) orthogonal test with 14 treatments totally, to compare the change of plant community productivity and plant diversity during three years of fertilization. We monitored the dynamic responses of aboveground biomass, plant species composition, species richness, Shannon diversity, Pielou’s evenness after nitrogen (N), phosphorus (P), and potassium (K) addition once a year from 2014 to 2016. Compared to the control treatment of no additional fertilizer, we found that, (1) The fertilization combination of N (274 kg ha^-1), P (350 kg ha^-1), and K (57 kg ha^-1) had a greater effect on biomass after the third year of fertilizer addition; (2) Gramineae accounted for a major portion of biomass in 2016, whereas the proportion of other species declined or disappeared; and (3) the longer the fertilization treatments went on, the lower Shannon diversity and Pielou’s evenness turned out to be. All these responses are strongly interrelated in a cascade of changes. The interrelationships between fertilizers and different plant communities attribute the change not only to climate shift but also to time. [ABSTRACT FROM AUTHOR]