Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2006.2881.2886Medicago sative Varieties]]>FajriAbolhassan 122006915An experiment was conducted to evaluate the effects of K (0, 50 and 100 kg K ha-1) on nitrogen fixation and dry matter production of three medicago (Medicago sativa L.) varieties (Hamadani, Sacoeal and Gharayoungeh), in the agricultural research station of Urmia University, West Azarbijan province. The performance management was under irrigating and cutting regime in a small-plot trial (1 m2) with low K soil. The experimental layout was a randomized complete block split-plot design with four replicates. Three plants from each plot at initial flowering stage were taken for measuring N2-fixation by using the natural abundance of 15N, dry weight of leaves, stems, nodules and nutrients (K, C) of the shoots. Nodule weights were estimated from root systems of plants prior to third harvest. The highest rate of nitrogen fixed from atmosphere in shoots of Gharayoungeh (122 kg ha-1) was obtained with the application of 100 kg K ha-1, whilst the lowest yield (83 kg ha-1) belonged to Sacoel in unfertilized plots. Both dry matter yield of stems and nodule weight were significantly increased by K fertilization. Dry matter yield of leaves in plants was reduced by K fertilization. K application increased the K, carbon contents of shoots of overall plant varieties by more than 50 kg K ha-1. These evaluations demonstrated that varieties responded to different levels of K fertilizer. Increased yield of stems and nodules, in contrast, reduction in leaf yield by K application indicated that carbon from photosynthesis is preferably used for stem production and nodule formation.]]>Atkins, C.A., D.F. Herridge and J.S. Pate,19781978pp: 211242Bergersen, F.J., M.B. Peoples and G.L. Turner,198815407420Blakemore, L.C., P.L. Searle and B.K. Daly,19811981Cadisch, G., R. Sylvester and J. Nosberger,198915N-Based Estimation of nitrogen fixation by eight tropical forage-legumes at two levels of P: K supply.]]>22181194Collins, M. and S.H. Duke,19812 fixation of alfalfa.]]>21481485Collins, M., D.S. Lang and K.A. Kelling,198678959963Hardy, R.W.F. and Havelka,19762 fixation as a problem in carbon.]]>1976Howard, D.D., M.E. Essington and D.D. Tyler,199991266269Ledgard, S.F., J.R. Simpson, J.R. Freney and F.J. Bergerson,198515N methods.]]>36663676Lynd, J.Q., E.A. Hanlon and G.V. Odell,198416589594Mahon, J.D. and J.J. Child,1979Pisum sativum) to combined nitrogen.]]>5716871693Peoples, M.B., A.W. Faizah, B. Rerkasem and D.F. Herridge,1989Peoples, M.B., A.M. Bowman, R.R. Gault, D.F. Herridge and M.H. McCallum et al.,20012282941Pfluger, R. and A. Cassier,19772 fixation.]]>1977Bern,pp: 95Pinkerton, A. and P.J. Randall,1993Lotus pedunculatus, Medicago murex, M. polymorpha, M. truncatula, Ornithopus compressus. Trifolium balansae, T. resupinatum. Pennisetum clandestinum and Phalaris aquatica.]]>333139Rayment, G.E. and F.R. Higginson,1992Pages: 330Pages: 330Ruiz, J.M., D.A. Moreno, G. Villora, J. Olivares, P.C. Garcia, J. Hermandez and L. Romero,2000Capsicum annuum L. cv. Lamuyo) in response to increases in N K Fertilization.]]>3123452357Gja, R., C.E. Powell and A.J. Gordon,197930145153Sherwood, M.T.,1970Rhizobium.]]>33708713Shi, W., X. Wang and W. Yan,20042611116Vincent, J.M.,1970Vincent, J.M.,19771977pp: 277-366pp: 277-366Yang, X.E., J.X. Liu, W.M. Wang, Z.Q. Ye and A.C. Luo,200427837852Yin, X.H. and T.J. Vyn,200395126132