Biol Fertil Soils (2002) 36:442–446 DOI 10.1007/s00374-002-0557-2 ORIGINAL PAPER T. S. Griffin · C. W. Honeycutt · Z. He Effects of temperature, soil water status, and soil type on swine slurry nitrogen transformations Received: 16 April 2002 / Accepted: 29 August 2002 / Published online: 14 November 2002  Springer-Verlag 2002 Abstract Manure N dynamics are affected by manure characteristics, soil factors, and environmental conditions. An incubation experiment was conducted to assess the relationship of these factors. The effects of temperature (11, 18, and 25C), soil texture (three soils, silt loam to sandy loam), and soil water status (constant at 60% water filled pore space, WFPS, and fluctuating between 30% and 60% WFPS) on net mineralization and nitrification of swine manure N were assessed. Swine manure was applied at an equivalent rate of 350 kg total N ha –1 to 250 g air-dry soil in 2-l canning jars. Subsamples were taken from each jar for NO 3 – and NH 4 + determination when fluctuating moisture treatment dried to 30% WFPS, with sampling continuing through four wet-dry cycles at each temperature. Manure NH 4 + was rapidly nitrified to NO 3 – . The relationship between NO 3 – accumulation and degree days after application (DDAA, 0C base) could be described across temperatures using a single pool expo- nential model for each soil. More NO 3 – accumulated in coarser-textured soils (150–200 mg N kg –1 soil), com- pared to 130 mg N kg –1 soil in the silt loam soil. Fluctuating soil water status did not alter estimates of rate and extent of NO 3 – accumulation, but slowed NH 4 + disappearance somewhat. Keywords Nitrogen · Mineralization · Nitrification · Manure slurry Introduction Transformations of N applied from manure or other organic amendments are affected by numerous biotic and abiotic factor. It is important to account for the individual and interactive effects of these factors in developing estimates of plant available N (PAN) from manures. Characteristics of the manure amendment clearly have a large impact on the availability of N. Castellanos and Pratt (1981) demonstrated large differences in the min- eralization of manure organic N from different ruminant and monogastric livestock species. In general, the avail- ability of N, measured as the accumulation of mineral N during a period of aerobic incubation, increased as manure N concentration increased. Gordillo and Cabrera (1997a) showed that within an animal species (e.g. poultry) the availability of N was influenced by manure characteristics, including uric acid and total N concen- tration. After application to soil, the transformations of N from a specific manure or slurry are controlled largely by three factors: temperature, soil water status, and soil type or texture. Hadas et al. (1983) showed that the accumulation of NH 4 + during the early stages of an aerobic incubation, indicative of organic N mineralization, increased with incubation temperature. Stark (1996) provided estimates of nitrification rate over a broad range of temperatures (5– 50C), with maximal rates occurring in the range 30– 35C. Grundmann et al. (1995) conducted a similar assessment, but found optimal temperatures to be 20– 25C. Under high soil water conditions, formation of N 2 O and loss of N via denitrification also increase with temperature (Maag and Vinther 1999). Griffin and Honeycutt (2000) showed that when soil water content was near-optimal, consumption of NH 4 + and accumula- tion of NO 3 – (i.e. net nitrification reaction) from different manures at temperatures of 10–24C could effectively be modeled using degree days after application (DDAA) to account for differences in temperature. The impact of soil water on N transformations is varied and in many cases has been related to the experimental procedures employed. Numerous incubation experiments have held soil water content constant at different levels. Stanford and Epstein (1974) provide an example of this approach, and concluded that soil N mineralization was a Mention of trade names or commercial products in this article is solely for the purpose of providing specific information, and does not imply recommendation or endorsement by the U.S. Department of Agriculture. T.S. Griffin ( ) ) · C.W. Honeycutt · Z. He USDA-ARS, New England Plant Soil and Water Laboratory, University of Maine, Orono, ME 04469–5753, USA e-mail: tgriffin@maine.edu