Analysis of regional distribution patterns and full utilization potential of crop straw resources

Crop straw is a valuable biomass energy resource and raw material for livestock forage, organic fertilizer and industrial use. However, the comprehensive utilization level of straw resources in China is not high due to various reasons including agricultural intensification, capital shortage and farmers’ cognition. Regional, seasonal and structural surplus of crop straw is common in China and a lot of straw is discarded and burned casually, especially in rural areas. It is not only a huge waste of resources, but also leads to serious atmosphere and soil environment pollutions. Thus, it is of great importance to improve the straw utilization rate. That take regional planning as a whole and realize full utilization of the regional total straw resources is a good strategy. Assessment of regional straw resources’ quantity, type, and distribution pattern is the prerequisite to achieve regional straw resources full utilization. In addition, the utilization modes and levels of straw resources are also restricted by many other factors including the social and economic development status. Thus, to make better use of straw resources and optimize utilization structure, it is necessary to take all the above factors into comprehensive consideration, carrying out scientific layout and rational planning. Hunan province is an important agricultural province and also a main producing area of double cropping rice in China. The present study estimated the straw quantity and amount per capita of the main crops in Hunan province. The spatial distribution patterns of straw resources in Hunan province were also analyzed. In addition, the paper also analyzed the potential of full utilization of the total straw resources in the province through comparing the current straw utilization structure and quantities with their corresponding competitive straw demands. The results showed that the theoretical and collectable amount of the main crop straw resources in Hunan province in 2018 were 4 021.7× 104 t and 3 039.1×104 t, respectively. The mean amount per capita of straw resource is only 0.68 t, which is much lower than the national average level. The straw of rice, rape, maize and vegetables accounted for 64.7%, 16.0%, 6.1% and 7.5% of the total straw resources of the Province, respectively. The various types of crop straws exhibited different spatial distribution patterns. The amount of rice, rape and vegetable straw increased from west to east and south to north in the province, whereas corn straw displayed an opposite distribution trend. Through estimating the potential utilization ways of straw resources, the competitive demand of straw in Hunan province included 887.3×104 t for fertilizer, 885.1×104 t for fodder, 65.7×104 t for raw material and 83.2×104 t for stroma material. The remaining amount of straw for potential energy utilization was 1 117.9×104 t. Considering the current straw utilization structure and the results as above, the overall trend of realizing full utilization in the province should be to improve the ratio of fodder and energy utilization and slightly reduce fertilizer utilization on the basis of maintaining the amount for stroma and raw material utilization.