Mechanism of the Original Ecology Gravity Irrigation in the Ziquejie Terrace

Abstract

The Ziquejie Terrace is one of the three famous ancient terraces in China. Rice has been planted in large area with mountains standing and a lot of steep hills. Whatever the weather is drought or rainstorm, the rice can always have a good harvest without water storage facilities. To reveal the mechanism of the original ecology gravity irrigation, several investigations had been developed such as observation of hydrology and meteorology, hydro-geological exploration and dynamic monitoring of groundwater level. According to the results of the experimental observations, this article proposed a suit of perfect theories and methods, such as the nonlinear autonomic regulation theory and “the ground water reservoir on the same slope position” theory in ancient terrace area. Further more, the calculation model of the original ecology gravity irrigation water cycle balance was established and a set of theories and methods of the water cycle balance calculation were formed on the basis of prior theories. Using this model, the process of irrigation water supply and demand balance, as well as the irrigation assurance, was simulated at rice growth stages in the original gravity irrigation area and its surrounding artificial irrigation area. The results showed that there is a highly consistency between the simulation results and the measured results, and it revealed the mechanism of ancient ecological gravity irrigation profoundly in terraces area. The result of study has important directive significance to the exploitation and protection of the terrace in China and has important reference value to the exploitation of the slope farmland.