Soil N transformation rates protocol
Description
Soil nitrogen transformation rates (potential net N transformation, mineralization, ammonification, nitrification and depolymerisation) (Schimel & Bennett, 2004) are measured by determination of the total K2SO4 or KCl extractable nitrogen (TAN), the available mineral N (NH4+-N and NO3--N) and the dissolved organic N (DON) forms before and after a soil incubation in the laboratory at 80% of water holding capacity (WHC) and 30°C for 14 days (Allen, Grimshaw & Rowland 1986), and extracted with K2SO4 0.5M or KCl 1M in a 1:10 ratio. The incubation, extraction and the colorimetric analyses of DON, NH4+-N and NO3-N in the soil´s extract are made following the procedure describe below. The amount of N forms in the soils is calculated using a linear calibration curve with standards and expressed as mgr N kg-1 soil and rates are expressed as mgr N kg-1 soil day-1.
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soil N transformation rates.pdf
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Additional details
References
- Allen, S.E., Grimshaw, H.M. & Rowland, A.P., 1986. Chemical Analysis. Methods in Plant Ecology. Blackwell Scientific, Oxford, UK.
- Schimel, J.P., Bennett, J., 2004. Nitrogen mineralization: challenges of changing paradigm. Ecology 85, 591-602.
- Sims, G.K., Ellsworth, T.R., Mulvaney, R.L., 1995. Microscale determination of inorganic nitrogen in water and soil extract. Communications in Soil Science and Plant Analysis 26, 303-316.
- Sollins, P., Glassman, C., Paul, EA., Swantson, C., Lajtha, K., Heil, JW., Ellikott, ET., 1999. Soil, carbon and nitrogen: pools and fraction. Standar soil methods for long-term ecological research. Oxford University, Oxford.