Alfalfa Biomass Production in Establishment Year under Different Phosphorus and Potassium Rates

Alfalfa is a perennial forage legume. Once successfully establish, it may give good regular foragesyield for 7 to 10 years. Nonetheless, biomass production in the establishment phase is complexed due to poorseedling growth. We compared two alfalfa varieties (i.e. Sardi-7 and NRC-15) with different phosphorus (i.e.40, 80 and 120 kg ha^-1) and potassium (i.e. 25, 50 and 75 kg ha^-1) rates. Field experiment was conducted at Agronomy Research Farm, University of Agriculture Peshawar in November 2015-16. Data were recordedperiodically on fresh matter in the first establishment year 2016 of maximum 10 cuts, hereafter referred assamplings in a year. Leaf to stem ratio were also monitored during the crop growth. While averaged on nutrients(P and K) application rates, the overall herbage production revealed almost same trend as fresh matterat initial six samplings (starting from March to August), which were also expressed in corresponding ThermalUnits (TU OC). From sampling 7, the NRC-15 variety remains fall dormant in the Peshawar’s climate. Potassiumresponse on the alfalfa biomass production was expressed at 4th sampling (i.e. May to Sep.) with highest(p 0.05) for K 75 kg ha-1 as compare to other two lower rates. Likewise, phosphorus effect expressed fromMarch to December samplings with highest for P 120 kg ha^-1, followed by P 80 kg ha^-1 and subsequently thelowest for P 40 kg ha^-1. Alfalfa production showed increase in the subsequent samplings excited from Marchto July and then decreased till December in the establishment year. Sprouts density is important for the initialstand establishment per unit ground area in early phase of the crop growth. Data revealed the highest density infirst three samplings when P was given 80 and 120 kg ha^-1. Maximum sprout density was observed in K 75 kgha^-1. Leaf to stem ratio did not show any promising response with the changing P or K levels. Results revealedthat both varieties differed in biomass production over months of the season. However, the response of biomass