Response of herbaceous vegetation to phosphorus fertilizer in steppe desert

Abstract

In desert ecosystems, low soil moisture and high soil alkalinity decrease phosphorus (P) bioavailability, which results in a scarcity of soil P. Low soil P availability limits plant growth, development and reproduction, and consequently P is one of the most important limiting factors for vegetation growth and restoration in desert ecosystems. Furthermore, productivity of most plant communities increases following nutrient addition, while species diversity shows different responses to nutrient addition. Nevertheless, little attention has been directed towards identification and quantification of P pools in water鄄limited desert ecosystems, and results of P fertilization experiments in non鄄arid regions are not applicable to arid regions receiving < 200 mm annual precipitation. The aim of this study was to understand the effects of artificial P addition on the vegetation structure of herbage synusia and to offer a solid basis for long鄄term restoration and scientific management of desert ecosystems. We selected the herbaceous vegetation in steppe desert on the southeastern margin of the temperate Tengger Desert, northern China, as a case study and collected data through field surveys after artificial addition of P fertilizer in spring. Phosphorus fertilizer was added in the first year, in which the annual precipitation was 271 mm (1. 4 times the average annual precipitation). In the second year, no P was applied and the annual precipitation was 127 mm. The species, number of individuals, height and coverage were recorded monthly. Using these data, we analyzed the