The pathway of sustainable straw management in China

Straw has dual characters: waste and resource. After crop harvest season, enormous straw is generated in China. With the improvement in farmers’ living, household use of straw is decreasing. On the contrary, the crop yield and straw are increasing simultaneously, which brings about a surplus of straw. Farmers have to choose either full straw return or straw burning in farmland. Considering the negative effects of full straw return, straw burning in the farmland is the cheapest and most convenient way to get rid of it. With the raising awareness of environmental protection, straw burning is strictly controlled by Chinese government. In addition, straw comprehensive utilization has been implemented, which can be helpful for consuming the straw resource, thereby reducing straw burning voluntarily.
However, it has four problematic issues with current practices of straw utilization, which hinder the transition from conventional straw management to sustainable straw management. Namely, diseconomy of straw disposal by dominant smallholder farmers; the uncertainty of optimal straw return scheme; the unreliability of straw feedstock supply chain modelling and lacking sustainable safeguard mechanism. Thus, the research objectives of the thesis are to provide countermeasures for addressing these issues.
To begin with, straw is created and generated on farmland after crop has been harvested, therefore how to consume it on farmland is the first step. Straw burning is prohibited, and then straw return is indispensable. So, this thesis first explores the optimal scheme of straw return, to maximize the benefit (crop yield increase) and determine the amount of straw return. Concerning the huge regional and crop-type differences, China’s corn belt (Northeast China) is chosen as a study area for exploring optimal scheme of straw return.
And then, in comparison with straw burning in farmland, adopting straw return practice requires extra costs. Eco-compensation with monetary incentive can stimulate farmers to choose to straw return practice voluntarily. Then this thesis explores the mechanism and reasons that farmers should be compensated for agronomic, environmental and ecological aspects, and policy suggestions for innovative incentives are given.
Furthermore, apart from a certain amount of straw resource that can be returned to farmland as organic fertilizer, the remaining straw resource (leftover) can be recycled for other purposes. For straw recycling, straw must be removed from farmland to the gate of utilization terminal. Therefore, straw feedstock supply chain is indispensable. Before the real and practical arrangement of straw feedstock supply chain, modelling is a useful method for providing important assistance. Then, this thesis fills the knowledge gap in establishing a straw feedstock supply model that could satisfy the specific conditions in China and ensures a stable and reliable straw supply with optimal arrangements and minimum costs.
Besides, how to make sure that this system can be operated smoothly and sustainably requires sustainable safeguard mechanism. The system of sustainable straw management is complicated, with the stakeholders of farmers, brokers, producers, consumers as well as the government. How to balance their interests and make benefits need tactical mechanism design. Therefore, this thesis will give policy suggestions on sustainable safeguard mechanisms to make sure that sustainable straw management can run on a long-time basis.
Moreover, the potential abatement of carbon emission with sustainable straw management has been assessed. Taking corn straw in Northeast China as a case study, the potential abatement of carbon emission is estimated to be 222.3 million tons of CO2 eq. annually. In addition, the potential solutions for practicing innovative incentives, and the extension of StrawFeed model with techno-economic models with agricultural production management have been clarified and discussed.
Finally, this thesis concludes that sustainable straw management is an important measure for straw valorisation and sustainable agriculture in China. This work supports that sustainable straw management in China can achieve multiple UN Sustainable Development Goals simultaneously, and the experience and lessons learned from China can also enlighten other developing countries faced with similar challenges.