How valuable is straw? Yin Chengjie: Straw is also a treasure
The "Recommendations" of the Fifth Plenary Session of the 18th Central Committee of the Communist Party of China proposed "promoting the resource utilization and harmless disposal of waste from crop farming and livestock breeding." Crop straw is the largest-volume waste from crop farming and livestock breeding, so let us take it as an example here to discuss the resource utilization of waste from crop farming and livestock breeding.
China is a major grain-producing country, and naturally also a major crop straw-producing country. Based on the current annual grain output of 600 million tons and a grain-to-straw ratio of 1:1.5, the theoretical output of crop straw is as high as 900 million tons. However, the effective utilization rate of straw is relatively low, and burning is common. The reason for this, apart from technical factors, is most critically outdated thinking and a failure to fully recognize the utilization value of straw. If so much straw could be resource-utilized and turned from waste into treasure, it would be a major benefit for sustainable agricultural development, farmers' income growth, and emission reduction and haze prevention.
In fact, crop farming inputs cultivated land, fresh water and other agricultural inputs, and what is grown and harvested is not only grain and fruit; straw is likewise an important crop output. In this sense, utilizing straw means utilizing part of the agricultural output. From the perspective of heat value, the combustion value of straw is about 50% that of standard coal. From the perspective of nutritional value, 1 ton of ordinary straw is on average nutritionally equivalent to 0.25 tons of grain. Under modern agricultural conditions, with advanced processing technology, crop straw is not only not waste, but also a very important agricultural product. Crop straw contains abundant solar energy and can be used to produce biomass energy, biomass building materials, feed, fertilizer, edible fungi and more, and has considerable development value.
Comprehensive utilization of crop straw can bring multiple effects. First, it optimizes the energy structure. Using crop straw for power generation, gasification and other renewable energy development is conducive to increasing the proportion of green energy in China's energy structure. Second, it protects the ecological environment. Reducing straw burning can greatly reduce emissions of gases such as carbon dioxide and sulfur dioxide, as well as heat and particulate matter, and alleviate haze pollution. Resource utilization of straw can also prevent long-term piling from spreading pests and diseases, which is conducive to crop pest and disease control. The plant ash produced by straw utilization is a high-quality potassium fertilizer that can replace part of chemical fertilizers and reduce agricultural non-point source pollution. Third, it promotes farmers' income growth. Once the value of crop straw is tapped, farmers can sell straw to relevant enterprises for income. This is an effective expansion of the field of farmers' income growth, and is also conducive to raising farmers' enthusiasm for growing grain, thereby achieving mutual promotion between developing biomass energy and ensuring food security. Fourth, it improves the utilization rate of agricultural resources. Comprehensive utilization of crop straw essentially improves the utilization rate of cultivated land, fresh water and other agricultural inputs, and raises the comparative efficiency of agriculture.
To strengthen the comprehensive utilization of crop straw, promote its conversion and value-added use, and continuously raise the level of rural circular economy development, the following basic work should be done well. First, strengthen research and development of comprehensive crop straw utilization technology. Focus on strengthening research and development of supporting technologies for the straw circular economy, strengthen research and development of related core technologies such as straw power generation, accelerate the pace of localizing complete sets of equipment, and reduce input costs. Accelerate the research, development and promotion of straw feed technology, and improve the equipment level of straw feed processing. Strengthen technology integration and supporting facilities, and improve the comprehensive straw utilization technology system. Second, strengthen crop straw resource management. Improve straw management measures, and further improve the mechanism for comprehensive straw utilization and circulation management. Increase funding input for comprehensive straw utilization, guide social capital investment, and support the construction of demonstration projects for comprehensive straw utilization. Third, attach importance to developing straw production. When optimizing the layout of crop farming, pay attention to considering straw resource utilization. Coordinate the development of crop farming, livestock breeding, the feed industry and biomass energy, and promote the scientific development of the rural circular economy. Fourth, formulate and improve straw utilization policies. Formulate reasonable straw purchase and utilization policies so that farmers obtain reasonable returns and their enthusiasm for protecting and utilizing straw is mobilized. Establish a management mechanism for straw collection, storage and transportation to ensure the quantity and quality of straw. Fifth, formulate quality standards and improve supervision and management. Scientifically formulate standards for the mechanical equipment and technical systems used in the process of converting straw into biomass energy, formulate quality standards for biomass energy products, and improve the product quality monitoring system to ensure quality and safety.