Growth and photosynthetic physiological characteristics of Leymus chinensis in response to applications of phosphorus at differing intensities

This study used pot experiments to explore how the growth and other photosynthetic physiological characteristics of Leymus chinensis responded to applications of phosphorus at four intensities (0, 70, 140, and 210 kg·ha⁻¹). The results showed the following. 1) Applications of phosphorus at rates ranging from 70～210 kg·ha⁻¹ increased the height and biomass accumulation of L. chinensis plants; the effects were most obvious at an application intensity of 140 kg·ha⁻¹. 2) The photosynthetic response of L. chinensis to different soil phosphorus application intensities varied. As the intensity of the phosphorus applied increased, the net photosynthetic rate first increased and then decreased. The maximum photochemical efficiency (F_v / F_m), PSⅡ activity, and initial fluorescence (F_o) of chlorophyll fluorescence occurred when phosphorus application intensity ranged from 70～140 kg·ha⁻¹, while F_o / F_m was at its minimum in these circumstances. An analysis of the fitted equation showed that a phosphorus application intensity of 148.75 kg·ha⁻¹ was the most favorable for the accumulation biomass by L. chinensis.