Pedotransfer functions for the pool size of slowly mineralizable organic N in sandy arable soils
- verfasst von
- Sabine Heumann, Jürgen Böttcher, Günther Springob
- Abstract
The major aim of this study was to evaluate how the pool size of slowly mineralizable, 'old' soil organic N can be derived from more easily accessible soil and site information via pedotransfer functions (PTF). Besides modeling, this pool size might be of great importance for the identification of soils with high mineralization potential in drinking-water catchments. From long-term laboratory incubations (ca. 200 days) at 35°C, the pool sizes of easily mineralizable organic N (Nfast), mainly in fresh residues, and slowly mineralizable, 'old' soil organic N (Nslow) as well as their first-order rate coefficients were obtained. 90 sandy arable soils from NW Germany served to derive PTFs for Nslow that were evaluated using another 20 soils from the same region. Information on former land-use and soil type was obtained from topographical, historical, and soil maps (partly from 1780). Pool size Nslow very strongly depends on soil type and former land-use. Mean pool sizes of Nslow were much lower in old arable lowland (105 mg N kg-1) than upland soils (175 mg N kg-1) possibly due to lower clay contents. Within lowlands, mean pool sizes in former grassland soils (245 mg N kg-1) were 2 to 3 times larger than in old arable soils due to accumulation of mineralizable N. In contrast, mean pool sizes of Nslow were lowest in recently cleared, former heath- and woodland (31 mg N kg-1) as a result of the input of hardly decomposable organic matter. Neither N nor C in the light fraction (density < 1.8 g cm-3) was adequate to derive pool size Nslow in the studied soils (r2 < 0.03). Instead, Nslow can be accurately (r2 = 0.55 - 0.83) derived from one or two basic soil characteristics (e.g. organic C, total N, C : N, mineral fraction < 20 μm), provided that sites were grouped by former land-use. Field mineralization from Nslow during winter (independent data set) can be predicted as well on the basis of Nslow-values calculated from PTFs that were derived after grouping the soils by former land-use (r 2 = 0.51 ***). In contrast, using the PTF without soil grouping strongly reduced the reliability (r2 = 0.16).
- Organisationseinheit(en)
-
Institut für Bodenkunde
AG Bodenbiophysik
- Typ
- Artikel
- Journal
- Journal of Plant Nutrition and Soil Science
- Band
- 166
- Seiten
- 308-318
- Anzahl der Seiten
- 11
- ISSN
- 1436-8730
- Publikationsdatum
- 01.06.2003
- Publikationsstatus
- Veröffentlicht
- Peer-reviewed
- Ja
- ASJC Scopus Sachgebiete
- Bodenkunde, Pflanzenkunde
- Ziele für nachhaltige Entwicklung
- SDG 15 – Lebensraum Land
- Elektronische Version(en)
-
https://doi.org/10.1002/jpln.200390048 (Zugang:
Unbekannt)
