Abstract:To study the dynamic growth and productivity of Hippophae rhamnoides L. subsp. sinensis under different water conditions, an annual growth model of H. rhamnoides L. subsp. sinensis in respect of height (new shoot) and ground diameter under polymorphic irrigation intensities was established with the dynamic growth increment data collected from experiments on the growth of H. rhamnoides L. subsp. sinensis under different water conditions simulated by field irrigation, and based on the polymorphic curves method in which the site index was replaced by the irrigation intensity. The results of study showed that: (1) There were differences in three parameters of the Logistic Model regarding to the height and grand diameter under different irrigation intensities: the differences in parameter K and parameter b were extremely significant (Sig.≤0.01) while the difference in parameter a was significant (0.01<Sig.≤0.05). (2) The multiple comparisons among 5 Biological Meanings of the growth model under different irrigations revealed that: The growth model of height and ground diameter had polymorphism caused by the differences of parameters leaded by different irrigation intensities. (3) When the irrigation intensity was 0~6 times more than rainfall, the parameter K and b in growth model of height and ground diameter accorded with the quadratic curve respectively, parameter a accorded with the power curve. These regression results contributed to the establishment of the polymorphic irrigation intensity growth model of H. rhamnoides L. subsp. sinensis in respect of height and ground diameter. (4) The analysis on the productivity of the polymorphic irrigation intensity growth model indicated that the increment in respect of height turned to be the greatest as the irrigation intensity was 4.83 times of the normal rainfall, while in respect of ground diameter, 4.53 times.