TY - JOUR

T1 - Field-specific simulations of net N mineralization based on digitally available soil and weather data

T2 - II. Pedotransfer functions for the pool sizes

AU - Heumann, Sabine

AU - Ringe, Horst

AU - Böttcher, Jürgen

N1 - Funding information: Acknowledgments We wish to thank Ms. Silke Bokeloh, Ms. Ulrike Pieper, and Ms. Elke Eichmann-Prusch for their dedicated work in the laboratory. The study was funded by the ‘‘Deutsche Bundesstiftung Umwelt’’ (German Federal Environmental Foundation), Osnabrück.

PY - 2011/12

Y1 - 2011/12

N2 - Avoiding surplus N fertilization without reducing crop yields could be accomplished by accounting for current net N mineralization in N fertilizer recommendations. N simulation models would allow a quantitative consideration of important factors and could be based upon digitally mapped data. Soil-specific temperature and water functions that were derived in part I of the paper needed a differentiation between only three soil groups and the two allocating criteria were taken from digital soil maps. Here, the objectives were to experimentally determine pedotransfer functions (PTFs) for the pool sizes of two organic N pools (Nfast, Nslow) that could be calculated via digitally available data and need a minimum set of easily accessible management data. Interestingly, most important input data for the PTFs of both pool sizes were mean clay contents of the texture class (German soil classification system). However, the underlying mechanisms might be different, as Nslow could be positively influenced by clay-associated mineralizable SOM, whereas Nfast could be positively related to clay content due to higher yield potential and thus more residues on finer-textured soils. For Nslow including the humus class improved the accuracy of the PTF (r2 = 0.60; P < 0.050). For Nfast it was important to include a negative influence of the mean fall temperature of the preceding year (r2 = 0.42; P < 0.010), probably due to its influence on residue degradation before winter. Surprisingly, easily accessible management data, e.g. previous crop, did not improve the predictions in this study. Field studies with plant cover will have to further prove the applicability of the derived PTFs.

AB - Avoiding surplus N fertilization without reducing crop yields could be accomplished by accounting for current net N mineralization in N fertilizer recommendations. N simulation models would allow a quantitative consideration of important factors and could be based upon digitally mapped data. Soil-specific temperature and water functions that were derived in part I of the paper needed a differentiation between only three soil groups and the two allocating criteria were taken from digital soil maps. Here, the objectives were to experimentally determine pedotransfer functions (PTFs) for the pool sizes of two organic N pools (Nfast, Nslow) that could be calculated via digitally available data and need a minimum set of easily accessible management data. Interestingly, most important input data for the PTFs of both pool sizes were mean clay contents of the texture class (German soil classification system). However, the underlying mechanisms might be different, as Nslow could be positively influenced by clay-associated mineralizable SOM, whereas Nfast could be positively related to clay content due to higher yield potential and thus more residues on finer-textured soils. For Nslow including the humus class improved the accuracy of the PTF (r2 = 0.60; P < 0.050). For Nfast it was important to include a negative influence of the mean fall temperature of the preceding year (r2 = 0.42; P < 0.010), probably due to its influence on residue degradation before winter. Surprisingly, easily accessible management data, e.g. previous crop, did not improve the predictions in this study. Field studies with plant cover will have to further prove the applicability of the derived PTFs.

KW - Digital soil maps

KW - N fertilizer recommendations

KW - Net N mineralization

KW - Parameterization

KW - Pool sizes

KW - Soil organic N

UR - http://www.scopus.com/inward/record.url?scp=81355132082&partnerID=8YFLogxK

U2 - 10.1007/s10705-011-9465-x

DO - 10.1007/s10705-011-9465-x

M3 - Article

AN - SCOPUS:81355132082

VL - 91

SP - 339

EP - 350

JO - Nutrient cycling in agroecosystems

JF - Nutrient cycling in agroecosystems

SN - 1385-1314

IS - 3

ER -