[Ecological stoichiometry of leaf and litter of herbaceous plants in loess hilly and gully regions, China].

This study was conducted in the forest, forest-steppe and steppe vegetation zones along the Yanhe River Basin, where the leaf and litter samples from four dominant herbaceous plants including Lespedeza davurica, Stipa bungeana, Artemisia sacrorum, Artemisia giraldii were taken. By measuring the concentrations of carbon (C), nitrogen (N), phosphorus (P) and potassium (K), we measured the concentrations and their ratios to explore the limit and resorption of nutrient in the herbaceous plants. The results showed that the leaf N/P of four herbaceous plants was all lower than 14, suggesting their growth was mainly limited by N content. Except for L. davurica, the mean nutrient resorption efficiency of K, N and P in the other three plants was 79.9%, 48.7% and 32.5%, respectively. The higher nutrient resorption efficiency and K concentration in the leaf were beneficial for soil water competition of A. sacrorum and A. giraldii. The litter C/N in A. sacrorum was significantly lower than that in S. bungeana and A. giraldii, which was easy to decompose to benefit the nutrient recycling. This resulted in the wide distribution of A. sacrorum in the three vegetation areas.