TY - JOUR

T1 - Pedotransfer functions for the pool size of slowly mineralizable organic N in sandy arable soils

AU - Heumann, Sabine

AU - Böttcher, Jürgen

AU - Springob, Günther

N1 - Copyright: Copyright 2008 Elsevier B.V., All rights reserved.

PY - 2003/6/1

Y1 - 2003/6/1

N2 - 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).

AB - 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).

KW - Pedotransfer functions

KW - Pool size

KW - Sandy arable soils

KW - Slowly mineralizable organic n

UR - http://www.scopus.com/inward/record.url?scp=0141989760&partnerID=8YFLogxK

U2 - 10.1002/jpln.200390048

DO - 10.1002/jpln.200390048

M3 - Article

AN - SCOPUS:0141989760

VL - 166

SP - 308

EP - 318

JO - Journal of Plant Nutrition and Soil Science

JF - Journal of Plant Nutrition and Soil Science

SN - 1436-8730

IS - 3

ER -