The soils of Pakistan are deficient in phosphorus and potassium thus there is a dire need to detect and recommend the optimum dose of these important nutrients for every crop. The present experiment was designed to study the response of crop stand establishment and grain yield of guar (Cyamopsis tetragonoloba L.) to potassium and phosphorous in a field trial at the University of Agriculture Peshawar, Pakistan during 2016. Three levels of phosphorus (40, 80, 120 kg ha^-1) and three levels of potash (20, 40, 60 kg ha^-1) along with control were applied to guar in randomized complete block design (RCBD) with three replications. Phosphorus and potassium were supplied from diammonium Phosphate and muriate of potash. Phosphorous had significantly affected emergence m^-2, days to pods formation, and grain yield. Maximum emergence m^-2 (54) and minimum days to pods formation (60) were recorded at 40 kg phosphorus ha^-1. Maximum grain yield (1120 kg ha^-1) was recorded at 120 kg phosphorus ha^-1. Potassium significantly affected emergence m^‑2, thousand-grain weight, and grain yield. Maximum emergence m^-2 (54) was recorded at 20 kg potassium ha^-1, maximum thousand-grain weight (42 g) was recorded at 40 kg potassium ha^-1 and maximum grain yield (1082 kg ha^-1) was observed at 60 kg potassium ha^-1. P and K significantly increased grain yield and thousand-grain weight compared with control. It is concluded that 40 kg phosphorous ha^‑1 and potassium 20 kg ha^-1 resulted in optimum yield of guar and recommended for general cultivation in agro-climatic conditions of Peshawar.

Key words: Guar, grain yield, potassium and phosphorus