Efficiency of phosphorus and nitrogen fertilization on improving steppe rangeland in semi-arid ecology

In this study, the effects of phosphorus and nitrogen fertilization on the successful improvement of a semi-arid steppe rangeland were recorded, which was in fair condition. The study was conducted in 2017 by using a 50 kg ha-1 P2O5, and different dosages (30, 60, 90, 120 kg ha-1) of nitrogen fertilizers and observations were recorded during 2018-2019 (2 years). Dry matter yield and forage quality parameters such as crude protein, neutral and acid detergent fiber contents were recorded to evaluate the performance of rangelands. All the fertilizers significantly increased dry matter yield; it was nearly doubled when P2O5 was applied and tripled when 90 or 120 kg ha-1 nitrogen was applied. Crude protein (CP) content was also affected by the fertilizers, but the effect of nitrogen was greater on CP content, which was four times higher (33.5–129.3 kg ha-1 CP) under 120 kg ha-1 nitrogen application when compared to a control group. Phosphorus slightly affected NDF content but had no significant effect on ADF content. Nitrogen fertilization did not affect NDF content but the ADF content was slightly decreased. Results indicated both phosphorus and nitrogen fertilization increased the yield and quality of forage. Hence, semi-arid steppe rangelands, which are in fair condition, need to be fertilized using 50 kg ha-1 phosphorus and 60 to 90 kg ha-1 nitrogen to improve their performance.