Evaluation of the land carrying capacity of major grain-producing areas and the identification of risk factors

Analyzing the risk factors in the land carrying capacity system of major grain-producing areas is crucial for the optimization of land management by decision makers. For that purpose, the major grain-producing areas (Heilongjiang Province) in China are used as an example, with 17 indicators, such as resource, social, economic, coordinated development of an ecological subsystem, selection of the coordination degree of water and soil, effective irrigation rate, grain yield and environmental protection investment rate. This paper establishes an evaluation index system for the land carrying capacity. In addition, on the basis of the values of each index, the initial values were obtained via multiple interval stochastic weight assignments; the evaluation criteria and the land carrying capacity level were determined using a cloud model, and the major risk factors were determined using the degree of risk for each index. The results indicated that the evaluation criteria for the land carrying capacity can be categorized within level I [0.02, 0.24], level II [0.24, 0.40], level III [0.40, 0.55], level IV [0.55, 0.70] and level V [0.70, 0.91]. The land carrying capacity exhibited a continuous rise at each observation station during representative years. The industrial structure and regional development directly affected the land carrying capacity. Therefore, the evaluation results were concluded to be reliable. The risk factors for the land carrying capacity system were different at different periods of time; they included the effective irrigation rate and net income per capita between 2001 and 2008 and transportation land use, solid waste and fertilizer consumption between 2009 and 2013. In addition, between 2001 and 2013, the risk source for the land carrying capacity system transitioned from economic and social subsystems to ecological and social subsystems. The research results provide a decision-making reference for the development, improvement and management of land resources in the study area.