TY - JOUR

T1 - N mineralization parameters of sandy arable soils

AU - Heumann, Sabine

AU - Böttcher, Jürgen

AU - Springob, Günther

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

PY - 2002/8/1

Y1 - 2002/8/1

N2 - The objective of this study was to experimentally investigate net N mineralization in sandy arable soils and to derive adequate N mineralization parameters for simulation purposes. Long-term incubations at 35°C were done for at least 200 days with 147 sandy arable soils from Northwest Germany. To cumulative net N mineralization curves the simultaneous two-pool first-order kinetic equation was fitted in order to differentiate between N mineralization from an easily decomposable, fresh organic matter pool (Nfast) and from a slowly decomposable pool (Nslow) of more humified OM. North German loess soils served as a reference, since available model parameters were mainly derived from those soils. Although curve patterns in sandy soils often somewhat deviated from typical double-exponential patterns, the mineralization equation generally could be fitted. Two pools were clearly revealed, but a transfer of the standard parameters was found to be not appropriate - except maybe for the pool size of the fast decomposable N pool. The mean k fast at 35°C (0.1263 d-1) is about 46% higher than the known 'standard' loess value, indicating better conditions for decomposition of fresh residues at this temperature. The mean kslow at 35°C (0.0023 d-1), which is 60% lower than reported earlier from loess soils, and much lower mineralization rates of the slowly decomposable N pool give reason to the presence of generally more resistant organic material in these sandy soils. The relation between Nslow and total N was found to be not close enough to derive the pool size of slowly decomposable N just from total N as done for loess soils. Reducing the variability is necessary, promising approaches exist. The eight reference loess soils revealed - on an average - the known N mineralization parameters.

AB - The objective of this study was to experimentally investigate net N mineralization in sandy arable soils and to derive adequate N mineralization parameters for simulation purposes. Long-term incubations at 35°C were done for at least 200 days with 147 sandy arable soils from Northwest Germany. To cumulative net N mineralization curves the simultaneous two-pool first-order kinetic equation was fitted in order to differentiate between N mineralization from an easily decomposable, fresh organic matter pool (Nfast) and from a slowly decomposable pool (Nslow) of more humified OM. North German loess soils served as a reference, since available model parameters were mainly derived from those soils. Although curve patterns in sandy soils often somewhat deviated from typical double-exponential patterns, the mineralization equation generally could be fitted. Two pools were clearly revealed, but a transfer of the standard parameters was found to be not appropriate - except maybe for the pool size of the fast decomposable N pool. The mean k fast at 35°C (0.1263 d-1) is about 46% higher than the known 'standard' loess value, indicating better conditions for decomposition of fresh residues at this temperature. The mean kslow at 35°C (0.0023 d-1), which is 60% lower than reported earlier from loess soils, and much lower mineralization rates of the slowly decomposable N pool give reason to the presence of generally more resistant organic material in these sandy soils. The relation between Nslow and total N was found to be not close enough to derive the pool size of slowly decomposable N just from total N as done for loess soils. Reducing the variability is necessary, promising approaches exist. The eight reference loess soils revealed - on an average - the known N mineralization parameters.

KW - Curve-splitting

KW - Long-term incubation

KW - Model parameters

KW - Net N mineralization

KW - Sandy arable soils

UR - http://www.scopus.com/inward/record.url?scp=0141941032&partnerID=8YFLogxK

U2 - 10.1002/1522-2624(200208)165:4<441::AID-JPLN441>3.0.CO;2-F

DO - 10.1002/1522-2624(200208)165:4<441::AID-JPLN441>3.0.CO;2-F

M3 - Article

AN - SCOPUS:0141941032

VL - 165

SP - 441

EP - 450

JO - Journal of Plant Nutrition and Soil Science

JF - Journal of Plant Nutrition and Soil Science

SN - 1436-8730

IS - 4

ER -