1- Baker A.V., and Mills H.A. 1980. Ammonium and nitrate nutrition of horticultural crops. Horticulture Reviews, 2: 395-423.
2- Blackshaw R.E. 2004. Application method of nitrogen fertilizer affects weed growth and competition with winter wheat. Weed Biology and Management, 4: 103-113.
3- Blackshaw R.E., Molnar L.J., and Janzen H.H. 2004. Nitrogen fertilizer timing and application method affect weed growth and competition with spring wheat. Weed Science, 52: 614-622.
4- Blackshaw R.E., Molnar L.J., and Larney F.J. 2005. Fertilizer, manure and compost effects on weed growth and competition with winter wheat in western Canada. Crop Protection, 24: 971–980.
5- Britto D.T., and Kronzucker H.J. 2004. Bioengineering nitrogen acquisition in rice: can novel initiatives in rice genomics and physiology contribute to global food security Bio-Essays, 26 (6): 683–692.
6- Cramer M.D., and Lewis O.A.M. 1993. The influence of NO3- and NH4+ nutrition on the carbon and nitrogen partitioning characteristics of wheat (Triticum aestivum L.) and maize (Zea mays L.) plants. Plant Soil, 154(2): 289-300.
7- Di Tomaso J.M. 1995. Approaches for irmproving competitiveness through the manipulation of fertilization strategies. Weed Science, 43: 491-497.
8- Evans J.R. 1989. Photosynthesis and nitrogen relationships in leaves of C3 plants. Journal of Oecologia, 78 (1): 9-19.
9- Geretharan T., Sangakkara U.R., and Arulnandh V. 2011. Effect of Purple Nutsedge (Cyperus rotundus) Population Densities on Onion (Allium cepa) as Influenced by Nitrogen in the Eastern Province of Sri Lanka. Tropical Agricultural Research, 22 (4): 348 –355.
10- Gholamhoseini M., Ghalavand A., and Jamshidi E. 2009. The Effect of irrigation regimes and fertilizer treatments on grain yield and elements concentration in leaf and grain of sunflower (Helianthus annuus L.). Journal of Pajouhesh and Sazandegi, 79: 91-100. (in Persian with English abstract)
11- Haas H., and Streibig J.C. 1982. Changing Patterns of Weed Distribution as a Result of Herbicide Use and other Agronomic Factors. Pages 57-79 in. LeBaron H.M., and. Streibig J.C., eds. Herbicide Resistance in Plants. New York: Journal Wiley.
12- Hassan Amin M.E. 2011. Effect of different nitrogen sources on growth, yield and quality of fodder maize (Zea mays L.). Journal of the Saudi Society of Agricultural Sciences, 10: 17-23.
13- Holm L.G., Plucknett D.L., Pancho V., and Herberger J.P. 1991. The World’s Worst Weeds: Distribution and Biology, Krieger Publ. Co. Malabar, FL. P. 610.
14- Iqbal J., and Wright D. 1997. Effects of nitrogen supply on competition between wheat and three annual weed species. Weed Research, 37: 391-400.
15- Jan M.T., Shah M., and Khan S. 2002. Type of N-fertilizer, rate and timing effect on wheat production. Sarhad Journal of Agriculture, 18 (4): 405-410.
16- Janat M. 2007. Efficiency of Nitrogen Fertilizer for Potato under Fertigation Utilizing a Nitrogen Tracer Technique. Communications in Soil Science and Plant Analysis, 38: 2401-2422.
17- Kmaystany N., Rezvani Moghaddam P., Fallahi J., Aqhvany Shajari M., Eskandari Nasrabad S., and Gndman F. 2011. Effect of nourishment resource on weed of anison farm species diversity. First National Conference on Strategies for achieving sustainable agriculture. University of Payme-nor Khuzestan. (In Persian)
18- Morales-Payan J.P., Santos B.M., Stall W.M., and Bewick T.A. 1998. Interference of Purple Nutsedge (Cyperus rotundus L.) population densities on bell pepper (Capsicum annuum) yield as influenced by nitrogen. Weed Technology, 12: 230-234.
19- Najibi SH. 2013. Effect of the type and amount of nitrogen fertilizer on emergence and growth of wheat (Triticum aestivum ), wild oat (Avena fatua) and lambsquarters (Chenopodium album). Master's thesis, Faculty of Agriculture, University of Birjand, Iran.
20- Okafor L.I., and Datta S.K.D. 1976. Competition between upland rice and purple nutsedge for nitrogen, moisture and light. Weed Science, 24: 43-46.
21- Rashed- Mohsel M.H., Najafi H., and Dokhteat-Akbarzadeh M. 2001. Biology and control of weeds. First Printing. University of Mashhad., P. 89-90.
22- Roostaa H.R., and Schjoerring J.K. 2007. Effects of Ammonium Toxicity on Nitrogen Metabolism and Elemental Profile of Cucumber Plants. Journal of Plant Nutrition, 30 (11): 1933-1951.
23- Santos B.M., Morales-Payan J.P., and Bewick T.A. 1996. Purple nutsedge (Cyperus rotundus L) interference on radish under different nitrogen levels. Weed Science Society of America Abstr, 36, 69.
24- Shangguan Z.P., Shao M.A., Ren S.J., Zhang M., and Xue Q. 2004. Effect of nitrogen on root and shoot relations and gas exchange in winter wheat. Bot. Bull. Acad. Sin. 45: 49-54.
25- Sinharoy A., Samui R.C., Ahsan A.K.M.M., and Roy B. 1996. Effect of different sources and levels of nitrogen on yield and yield attributes of sesame cultivars. Environment and Ecology, 8: 211-215.
26- Spheri A., Modares sanavi A.M., Gharh riyazi B., and Yamini Y. 2002. Effect of water deficit and different nitrogen rates on growth and development stage, yield and yield component of maize (Zea mays L.). Journal of Crop Sciences of Iranian, 4 (3): 184-200. (In Persian)
27- Wang L., Xiang C.H., and Wang Y. 2005. Studies on the Nitrate Content of Different Pak-choi Genotypes. Acta Horticulturae Sinica, 31 (1): 43-46.
28- Wang Z.R., Rui Y.K., Shen J.B., and Zhang F.S. 2008. Effects of N fertilizer on root growth in Zea mays L. seedlings. Spanish Journal of Agricultural Research, 6 (4): 677-682.