The effects of temperature and water potential on nitrification were investigated in two Iowa soils treated with Stay-N 2000. The soils were incubated at 10, 20, and 30 °C after soil water potentials of -1, -10, or -60kPa were applied to each soil. A first-order equation was used to calculate the maximum nitrification rate (Kmax), duration of lag period (t'), period of maximum nitrification (Δt), and termination period of nitrification (ts). The highest Kmax were 18 and 24mgkg-1d-1 nitrate (NO3-)-nitrogen (N), respectively, at 30 °C and -10kPa in both the Nicollet (fine-loamy, mixed, superactive, mesic Aquic Hapludoll) and Canisteo (fine-loamy, mixed, superactive, calcareous, mesic Typic Endoaquoll) soils and reduced to 4 and 16mgkg-1d-1 NO3--N when Stay-N 2000 was added. The extension of t' due to the addition of Stay-N 2000 was as high as 7d in the Nicollet soil at 10 °C and -1kPa and as little as 2d in the Canisteo soil at 20 °C and -10kPa.
- Matric potential
- Nitrification inhibitor