1. Allen, R.G., Raes, L.S., Smith, D.M., 1998. Crop evapotranspiration. Irrigation and drainage. Guidelines for Computing Crop Water Requirements, Paper, 56. FAO, Rome.
2. Relative rates of nitric oxide and nitrous oxide production by nitrifiers, denitrifiers and nitrate respirers;Anderson;Appl. Environ. Microbiol.,1986
3. Association of Official Analytical Chemists., 2000. Official Methods of Analysis (17th ed.), AOAC, Washington, DC.
4. Influence of urea fertilization and urease inhibithors on the size and activity of soil microbial biomass under conventional and zero tillage at two sites;Banerjee;Can. J. Soil Sci.,1999
5. Bouwman, A.F., Boumans L.J.M., Batjes N.H., 2002. Modeling global annual N2O and NO emissions from fertilized fields, Global Biogeochem. Cycle. 16, Art. No. 1080. .