**Abstract**

Grasslands in the Ethiopian highlands have been degrading with grazing loads. Fertilizers like nitrogen, phosphorus and sulfur improves the soil fertility and species composition of the grazing lands. This study justifies, evaluation of top dressing nitrogen and phosphorus fertilizers on biomass yield of grass lands for market-oriented livestock production studied at Chosha kebele, Southern Ethiopia in 2017. Three fertilizer levels ((T1), 150 kg ha−1 urea (T2) and combination of 110 kg ha−1 urea and 100 kg ha−1 NPS (T3)) were laid out in randomized complete block design with 6 replications in summer and winter cropping seasons. Dry matter yield was significantly (P<0.001) different among treatments and higher results were obtained for combination of urea and NPS, followed by urea and the control one. Higher grasses species composition between application of combination of urea and NPS than urea alone. Net revenue is higher in nitrogen alone application than nitrogen and phosphorus. Therefore, better marginal rate of return (MRR=828%) recorded in Urea application for grazing land improvement in Gamo highland areas. It is recommendable to apply 150 kg/ha urea fertilizer to bring optimum yield of grazing land in Southern Ethiopian Highlands.

**Keywords:** Nitrogen, Phosphorus, grazing land, dry matter, species composition
