Fundamental theories and technologies foroptimizing the production functions and ecological functions in grasslandecosystems

Optimizing the production functions and ecological functions in grassland ecosystems is of fundamental importance to grassland ecology and management. Here we summarize the progresses in pratacultural systems worldwide, with an emphasis on major limitations of the pratacultural systems in China. We propose six important hypotheses and theories that can be used to guide grassland management, including grazing optimization hypothesis, intermediate disturbance hypothesis, accelerating nutrient cycling hypothesis, decelerating nutrient cycling hypothesis, forage supply-demand balance theory, and grassland-agriculture system theory. We also propose a framework with three major aspects of technologies in eco-pratacultural systems, including how to restore the degraded grasslands, how to sustainably use the natural grasslands, and how to establish artificial grasslands. Finally, we put forward the rules for establishing eco-pratacultural systems with optimization of the production functions and ecological functions. This review has important implications for the management of eco-pratacultural systems in China and beyond.