Temporal and spatial distribution of crops straw and its comprehensive utilization mechanism in Shaanxi

The crop straw as a kind of renewable biological resource is of high utilization value. In order to make full use of crop straws, it is necessary to analyze the distribution, current utilization situation and factors influencing straw resource utilization efficiency. Based on the data from the Shaanxi Statistical Yearbook 2010, the yield of crop straw from 1978 to 2009 in Shaanxi province and its variation tendency were determined, and its distribution characteristics in Shaanxi province in 2009 were analyzed with ArcVIEW 3.3 software. Moreover, through in-site investigation, the crop straw utilization in Shaanxi province in 2009 was also discussed. A Logistic model based on the data obtained from in-sites investigation was established to investigate factors affecting the utilization efficiency of crop straws. The results revealed that, from 1978 to 2009, the total crop straw yield in Shaanxi province presented a slowly rising trend, which had reached 16.8224 million tons by 2009. The main sources of crop straws were wheat, maize and other cereal crops, accounting for 90%. Guanzhong area and Northern Shaanxi area contributed most to the high yield. In Guanzhong area, crop straws from wheat and maize amounted to 85% of its total. In Northern Shaanxi, the proportion of crop straws deriving from maize straw and other cereal exceeded 60%. The distribution was closely related to local crop cultivation structure. The straw utilization patterns varied greatly in Guanzhong area, Northern Shaanxi and Southern Shaanxi. In Southern and Northern Shaanxi, crop straws were mainly used as fuels and forages, which took up 68.20%, 60.33% and 28.49%, 38.63%, respectively. Whilst in Guanzhong area, 12.82% of straws were burned directly in the field, 57.49% were taken back home as fuels, and 17.52% were returned to the field as organic fertilizer. It could be found that the comprehensive utilization of crop straws in Shaanxi province is less efficient, this is attributed to the geographical features, local customs and economic development levels. Mathematical model was applied to analyze the mechanism of present situation of crop residue utilization. The results showed that the induced variables were significantly affected by the sex, literacy level, revenue structure, whether there are village cadres or not, whether there are livestock breeding or not, awareness of straw usage, anticipated benefits for straw comprehensive utilization, whether there are processing enterprises or recycling companies, the availability of feasible technology for straw utilization, local agricultural mechanization level, governmental efforts for banning straw burning and punishment, and the geographic features. It indicates that the governmental policies, technology level, geographic features, famer’s economic level and individual willingness are the main factors affecting the straw utilization patterns. In order to improve the crop straw utilization efficiency and reduce environmental pollution in Shaanxi, it is quite necessary to take geological features and famers’ present economic condition into account, provide policy and technological guidance and enhance farmers’ awareness for comprehensive utilization.