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Stress relaxation behavior is an important mechanical property of wheat (Triticum aestivum L.) straw densifi ed biofuel. In this study, 21 cultivars of wheat straw were collected and their lignocellulose components (cellulose, hemicellulose, and lignin) were analyzed. Th e cellulose, hemicellulose, and lignin contents in these wheat straws ranged from 39.46 to 47.56%, from 30.39 to 35.98%, and from 5.54 to 12.12%, respectively. Stress relaxation tests of wheat straw were performed on an Instron testing machine. It was found that the wheat straw stress relaxation data had a two-stage characteristic, in which >80% of the total relaxed stress was rapidly released in the initial 10 s, and the stress relaxation was subsequently dominated by a slow stage until an equilibrium stress was reached. Four constitutive models including the Peleg model, the generalized Maxwell model, the Zener model, and the fractional Zener model were proposed to describe this stress relaxation behavior. Th e results showed that the fractional Zener model gave the best predictions of the wheat straw stress relaxation behavior, followed by the generalized Maxwell model, the Peleg model, and the Zener model. Th e relationship between stress relaxation behavior and wheat straw lignocellulose components was also further investigated. Th e fractional derivative coeffi cient decreased and increased with the increase of cellulose and hemicellulose + lignin contents, respectively. We suggest that the elasticity and viscosity of the wheat straw stress relaxation behavior is closely related with its lignocellulose components.

Environmental degradation is closely related to unreasonable land use behaviors by farmers. In this study, participatory rural assessment (PRA) is used to conduct a detailed survey of farmers and plots and to collect relevant natural and social statistics. The accuracy of remote sensing data is verified by comparative analysis, and the change in status of various land use types in each research period is reflected by the change in the dynamic degree and change in range. We examine how farmers’ attitudes and behaviors affect environmental degradation, using a sample of 403 farmers in China’s Manas River Basin. Due to age, education, income and other differences, farmers’ land use behaviors, as well as their attitude toward and feelings about environmental degradation, vary greatly. We found that most farmers considered the environment to be very important to their lives and crop production, but nearly 21% did not know the causes of environmental degradation and nearly 8% did not consider the environmental impacts of their crop production activities. A new model for oasis expansion—land integration—is presented here. This model can increase the area of cultivated land, reduce cultivated land fragmentation, save irrigation water, improve the field microclimate and form a good ecological cycle. Through land transfer, ecological compensation and ecological protection incentives, the government should guide farmers’ land use behaviors toward cooperation with the river basin’s ecological protection and land use planning.

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