Bioenergy feedstock supply from wheat straw: A farm level model incorporating trade-offs in crop choices, disease risk, and soil fertility

Second-generation biofuel (e.g., ethanol, renewable diesel) can be made from crop residues. However, the availability of residues for biofuel production is uncertain, because farmers have the option to grow different crops and use the residues for alternative purposes, such as livestock bedding and feed, or leave them in the field to improve soil quality. Taking Canadian wheat straw supply as an example, we develop a dynamic programming model to investigate a farmer's wheat straw supply decision in response to different wheat straw and grain prices. Our model considers crop choices between wheat and canola in the context of disease risk, the trade-off between the immediate payoffs a farmer may receive from bailing and selling wheat straw, and the long-term adverse effects that removing wheat straw from the soil surface may have on wheat and canola yields. The results from this study provide insights into how farm-level supply decisions, in response to wheat straw price changes, affect soil quality dynamics and scale up to regional wheat straw supply for biofuel production. This information also has implications for land use change and the sustainability of feedstock supply for biofuels.