Abstract:

Aims Improved rangeland management activities, such as prohibiting grazing, contribute significantly to increased carbon storage in grassland at low cost. Estimating carbon sequestration is important to evaluating cost and potential of carbon sequestration in grassland. We described and compared two methods for estimating carbon sequestration, stock-difference and gain-loss, in order to assess their suitability and accuracy for estimating cost of carbon sequestration in grassland.

Methods Using the grassland in Xilin River Basin of Inner Mongolia as a case study, we estimated the amount and cost of carbon sequestration by the stock-difference and gain-loss methods and compared results through sensitivity analysis.

Important findings There are significant differences in the amount and cost of carbon sequestration between the two methods, because of different grazing intensities. The cost of carbon sequestration is a function of grazing intensity and size of study area, with a linear relationship between cost and grazing intensity and a nonlinear relationship between cost and size of study area. The gain-loss method is more sensitive to grazing intensity and size of study area. The stock-difference method is more accurate and suitable for estimating cost of grassland carbon sequestration. However, the main reason for the difference between the two methods is different conditions of study areas. The two methods are essentially the same with regard to grassland succession. With sufficient data, both methods to estimate the amount and cost of carbon sequestration in grassland will give similar results.

Key words: Stock-difference method, Gain-loss method, prohibited grazing, cost of carbon-sequestration, Leymus chinensisgrassland