Nitrogen mineralization rates in ten surface soils amended with (200？μg N g？1 soil) or without broiler litter were investigated. The soil-broiler litter mixture was incubated at for 28 weeks. A nonlinear regression approach for N mineralization was used to estimate the readily mineralizable organic N pools ( ) and the first-order rate constant (k). The cumulative N mineralized in the nonamended soils did not exceed 80？mg N kg？1 soil. However, in Decatur soil amended with broiler litter 2, it exceeded 320？mg N kg？1 soil. The greatest calculated of the native soils was observed in Sucarnoochee soil alone (123？mg kg？1 soil) which when amended with broiler litter 1 reached 596？mg N kg？1 soil. The added broiler litter mineralized initially at a fast rate (k1) followed by a slow rate (k2) of the most resistant fraction. Half-life of organic N remaining in the soils alone varied from 33 to 75 weeks and from 43 to 15 weeks in the amended soils. When was regressed against soil organic N ( ) and C ( ), positive linear relationships were obtained. The pools increased with sand but decreased with silt and clay contents. 1. Introduction In general, nitrogen (N) is said to be the most difficult nutrient to manage in agriculture because of challenges in estimating the amount of N available for plant uptake and synchronizing N release from sources to meet a specific crop demand . Even though the Earth’s atmosphere contains 78% N in the form of dinitrogen (N2) gas, most of this N is unavailable for plant uptake  with the exception of leguminous plants which can fix N. In the plant root zone, N is present in organic forms, including plant and microbial protein and amino acids, all together forming soil organic matter  from which the N is slowly converted into plant-available forms. During mineralization, organic N is converted into plant-useable inorganic forms ( –N and, –N) that are released into soil and subjected to various fates. For farmers in general and organic farmers in particular, N mineralization is an important process to understand because several environmental conditions govern this process . Presently, there is an array of commercial inorganic N fertilizers available; however, their costs are prohibitory and out of range for many limited resource farmers. Thus, a careful management of organic N sources is one of the most important priorities for farmers; this in turn will limit unfavorable N losses into the environment. Because of the rapid growth of the organic farming segment of the United States agriculture, there is a high demand for
P. A. Moore, T. C. Daniel, D. R. Edwards, and D. M. Miller, “Effect of chemical amendments on ammonia volatilization from poultry litter,” Journal of Environmental Quality, vol. 24, no. 2, pp. 293–300, 1995.
J. A. Delgado, Potential Use of Innovative Nutrient Management Alternatives to Increase Nutrient Use Efficiency, Reduce Losses, and Protect Soil and Water Quality, Special Issue of the Journal of Communications in Soil Science and Plant Analysis, Marcel Dekker, New York, NY, USA, 2001.
K. Kpomblekou-A, “Relative proportion of inorganic and total nitrogen in broiler litter as determined by various methods,” Journal of the Science of Food and Agriculture, vol. 86, no. 14, pp. 2354–2362, 2006.
H. O. Liechty, M. A. Blazier, J. P. Wight, L. A. Gaston, J. D. Richardson, and R. L. Ficklin, “Assessment of repeated application of poultry litter on phosphorus and nitrogen dynamics in loblolly pine: implications for water quality,” Forest Ecology and Management, vol. 258, no. 10, pp. 2294–2303, 2009.
W. J. Wang, C. J. Smith, and D. Chen, “Predicting soil nitrogen mineralization dynamics with a modified double exponential model,” Soil Science Society of America Journal, vol. 68, no. 4, pp. 1256–1265, 2004.
J. A. E. Molina, C. E. Clapp, and W. E. Larson, “Potentially mineraizable nitrogen in soil: the simple exponential model does not apply to the first 12 weeks of incubation,” Soil Science Society of America Journal, vol. 44, pp. 442–443, 1980.
J. M. Bremmer and C. S. Mulvaney, “Nitrogen-total,” in Agronomy, A. L. Page, H. R. Miller, and D. R. Keeney, Eds., vol. 9, part 2, pp. 595–624, American Society of Agronomy, Madison, Wis, USA, 2nd edition, 1982.
D. R. Keeny and D. W. Nelson, “Nitrogen-Inorganic forms,” in Agronomy, A. L. Page, R. H. Miller, and R. D. Keeney, Eds., vol. 9, part 2, pp. 642–698, American Society of Agronomy, Madison, Wis, USA, 2nd edition, 1982.
J. L. Smith, R. R. Schobel, B. L. McNeal, and G. S. Campbell, “Potential errors in the first-order model for estimating soil nitrogen mineralization potentials,” Soil Science Society of America Journal, vol. 44, pp. 996–1000, 1980.
C. M. Gilmour, F. E. Broadbent, and S. M. Beck, “Recycling of carbon and nitrogen through land disposal of various wastes,” in Soils for Management of Organic Wastes and Waste Waters, L. E. Elliot and F. J. Stevenson, Eds., Soil Science Society of America, 1977.
I. J. Manguiat, I. Watanabe, G. B. Mascari？a, and J. G. Tallada, “Nitrogen mineralization in tropical wetland rice soils: I. Relationship with temperature and soil properties,” Soil Science and Plant Nutrition, vol. 42, no. 2, pp. 229–238, 1996.
V. Z. Antonopoulos, “Comparison of different models to simulate soil temperature and moisture effects on nitrogen mineralization in the soil,” Journal of Plant Nutrition and Soil Science, vol. 162, no. 6, pp. 667–675, 1999.
K. R. Sistani, A. Adeli, S. L. McGowen, H. Tewolde, and G. E. Brink, “Laboratory and field evaluation of broiler litter nitrogen mineralization,” Bioresource Technology, vol. 99, no. 7, pp. 2603–2611, 2008.
P. Sorensen, E. S. Jensen, and N. E. Nielsen, “The fate of 15N-labelled organic nitrogen in sheep manure applied to soils of different texture under field conditions,” Plant and Soil, vol. 162, no. 1, pp. 39–47, 1994.