After the policy of separating ownership rights, contract rights, and management rights to rural land, some Chinese farmers entrusted their land to agricultural social service providers. However, at present in land trusteeships, short-term behaviors exist, which are not good for the sustainable utilization of land. This article uses a dynamic game model to analyze the economic reasons for short-term behavior and to explore possible mechanisms. The study's results showed that fluctuations in trusteeship prices encouraged farmers to sign low-price, long-term contracts or high-price, short-term contracts that allowed agricultural social service providers choose short-term behaviors. A variable-price system may avoid short-term contracts as a result of fluctuations in trusteeship prices, allowing both sides to build a long-term stable partnership, encouraging long-term investment in land. To ensure the sustainable utilization of land, it is suggested that both sides adopt a variable price system.

In this paper, based on the time series of Brent crude oil prices (daily spot),by introducing some functions to explore empirically the price dynamics and behaviors in crude oil prices, we investigate the information in price system and analyze the price behaviors especially the system memory mechanism of historical information, thus we discuss the longterm memory mechanism existed and analyze numerically the non-periodic cycles in the system; furthermore, we find nontrivial fractal features and multi-affine spectra in Brent price system; finally, we calculate the two-time autocorrelation functions and get exponential decay for small values. All numerical results support that there exist stylized facts in Brent crude oil price system.