Background: Festuca kryloviana is a significant native grass species in the Qinghai Lake region, and its low emergence rate is a primary factor limiting the successful establishment of cultivated grasslands. The region’s arid and low-rainfall climate characteristics result in reduced soil moisture content at the surface. Despite the recognized impact of water availability on plant growth, the specific role of moisture in seedling development remains not fully elucidated. This study aims to investigate the germination rate and seedling growth velocity of F. kryloviana seeds under varying moisture conditions, and to integrate physiological and transcriptomic analyses of seedlings under these conditions to reveal the mechanisms by which water influences seedling development. Results: The emergence rate of F. kryloviana seedlings exhibited an initial increase followed by a decrease with increasing moisture content. The highest emergence rate, reaching 75%, was observed under 20% soil moisture conditions. By the eighth day of the experiment, the lengths of the plumules and radicles under the optimal emergence rate (full water, FW) were 21.82% and 10.87% longer, respectively, than those under closely matching the soil moisture content during the background survey (stress water, SW). The differential development of seedlings under varying moisture regimes is attributed to sugar metabolism within the seeds and the accumulation of abscisic acid (ABA). At FW conditions, enhanced sugar metabolism, which generates more energy for seedling development, is facilitated by higher activities of α-amylase, sucrose synthase, and trehalose-6-phosphate synthase compared to SW conditions. This is reflected at the transcriptomic level with upregulated expression of the α-amylase (AMY2) gene and trehalose-6-phosphate synthase (TPS6), while genes associated with ABA signaling and transduction are downregulated. Additionally, under FW conditions, the expression of genes related to the chloroplast thylakoid photosystems, such as photosystem II (PSII) and photosystem I (PSI), is upregulated, enhancing the seedlings’ light-capturing ability and photosynthetic efficiency, thereby improving their autotrophic capacity. Furthermore, FW treatment enhances the expression of the non-enzymatic antioxidant system, promoting metabolism within the seeds. In contrast, SW treatment increases the activity of the enzymatic antioxidant system, including peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT), to cope with water stress. Conclusions: Our experiment systematically evaluated the impact of moisture conditions on the growth and development of F. kryloviana seedlings. Physiological and transcriptomic data collectively indicate that adequate water (20%) supply enhances seedling growth and development by reducing ABA levels and increasing α-amylase activity within seeds, thereby boosting sugar metabolism and promoting the growth of seedling, which in turn leads to an improved emergence rate. Considering water management in future cultivation practices may be a crucial strategy for enhancing the successful establishment of F. kryloviana in grassland ecosystems.

Artificial grasslands of F. kryloviana in the region surrounding Qinghai Lake have been observed to a decline in productivity following three years of establishment. Traditional fertilization practices, aimed at maintaining ecological balance, have predominantly focused on the application of phosphorus. However, it remains unclear whether phosphorus fertilizers offer a superior advantage over nitrogen fertilizers in sustaining productivity. Consequently, from 2017 to 2019, we conducted an experimental to assess the impact of nitrogen and phosphorus fertilization on forage yield and quality. We designed with four levels of phosphorus and two levels of nitrogen, resulting in eight distinct fertilizer combinations. Our experimental findings indicate that the degradation of artificial grasslands leads to a shift in the allocation pattern of aboveground biomass. There was a respective decrease of 68.2 % and 62.5 % in the biomass proportions of stems and ears, contrasted by a greater than 200 % increase in the biomass proportion of leaves. The application of nitrogen not only elevated the total aboveground biomass but also promoted a preferential allocation of biomass to stems and leaves, consequently enhancing the forage's crude protein content. Nitrogen fertilization significantly increased aboveground biomass, and crude protein content by 63.21 %, and 6 %, respectively. Phosphorus fertilization's impact varied annually but favored the distribution of biomass to stems and ears. The net photosynthetic rate improved by over 53.12 % with fertilizer application, although the differences among treatments were not statistically significant. The balanced application of nitrogen and phosphorus fertilizers significantly bolstered the aboveground biomass, ear biomass, stem biomass, leaf biomass, and crude protein content in varying years by 17.25 %–209.83 %, 34.7 %–438.9 %, 25.5 %–250.2 %, 18.4 %–133.3 %, and 10.21 %–25.62 %, respectively. Our analysis revealed that nitrogen-only fertilization exhibited the most optimal fertilizer use efficiency and economic returns. In conclusion, nitrogen fertilization is crucial for sustaining the productivity and quality of F. kryloviana artificial grasslands. The local practice of 75 kg ha⁻¹ phosphorus fertilizer is detrimental to the maintenance of productivity in F. kryloviana artificial grasslands. This study offers valuable insights into the optimization of fertilization strategies for sustainable forage production within alpine regions.