FERTILIZATION AND SOIL AERATION EFFECTS ON GRASSLAND PRIMARY PRODUCTIVITY AND SPECIES DIVERSITY IN A MEADOW STEPPE, NORTHERN CHINA

摘要

In the grassland ecosystem, soils are subjected to a range of stresses which may affect their physical and biological properties, as well as the plant community biomass. As biomass is affected by long-term soil properties, we sought to establish a direct link between biomass and resilience to fertilization and soil aeration. We evaluated biomass yield in grasslands managed across a gradient of nitrogen (N), phosphorus (P), and potassium (K) fertilizers at Hulunbuir in Inner Mongolia, China, from 2014 to 2017. Based on the estimates from the simulated optimization and optimal theoretical regression model, we recommend applying N (231.50–238.82kg ha-1 ), and P (187.25–218.75 kg ha-1 ), and K (28.28– 33.32 kg ha-1 ) annually to maximize biomass in the non-aerated grassland. The positive effect of nitrogen and phosphorus on biomass was significantly higher than unfertilized treatment. The effects of aeration on biomass were less explicit. Simultaneously, we compared the Shannon-Wiener Index and Species richness for the suitable fertilizer levels. Shannon-Wiener diversity and Species richness became lower the longer the fertilization treatments lasted. Thus, nutrient resorption is resulting in a decrease in species diversity and richness, while it is an important strategy for increasing plant biomass.