EocBin

Results presented in this app are based on the N mineralisation model SNOMIN (Berghuijs et al. 2024) and the soil water balance model (WaterUptModule) from Tipstar (Jansen, 2008). Represented with an brown  line is the predicted total mineralised N from the soil organic matter in the crop rooting zone (top 30 cm) of the soil at a specified timepoint (date), since the beginning of the year. This is denoted in the graph as mineralised N from soil organic matter.

Analysed amendment properties such as organic matter content, C/N content and apparent initial age (Janssen 1984) are used to estimate N mineralisation from an amendment applied to the soil, and is denoted with the orange line. This is the amount of N estimated to be available for crop use, without considering N losses.

N losses due to soil leaching from the bottom of the rooting zone (top 30 cm) is denoted by the green line. This assumption of leached N is calculated for bare soil without growing crops to take up mineral N. The amount of N soil losses is expected to be lower in real time since crops will take up part of the mineral N available in the rooting zone, that would otherwise be completely leached.

Total N applied is denoted with a blue line and calculated as the sum of N applied to the field from both chemical fertilizer and organic amendment application.

Based on this information, end-users may deduce how the amount of N available to the crop develops over a growing season. This can be used to reduce the total quantity of chemical fertilizer to be applied as top or side dressing. Furthermore, the app estimates mineralised N at future dates, which can also be taken into account when calculating the quantity of chemical fertilizer as top or side dressing.

For example, total N applied to the soil to support optimal potato growth and tuber harvest is 250 kg N/ ha. This may consist of a basal dressing of 175 kg N/ ha and the remaining N, 75 kg N/ ha, is added to the soil as top or side dressing. If 25 t/ ha of a specified soil amendment is applied, containing 1 kg N/ t fresh soil amendment, and the app indicates that 37 kg N/ ha mineralises from the specified amendment within the growing season, then the intended chemical fertilizer as side- or top-dressing of 75 kg N/ ha may be reduced by 37 kg N/ ha.

Aknowledgement

The App is supported by co-funding by the European Union as Horizon Europe research and innovation Grant n° 101081858 (ECONUTRI) and Grant n° 101113011 (BIN2BEAN).

References

Berghuijs H.N., J.V. Silva, P. Reidsma and A.J. de Wit, 2024. Expanding the WOFOST crop model to explore options for sustainable nitrogen management: A study for winter wheat in the Netherlands. European Journal of Agronomy 154, 127099. https://doi.org/10.1016/j.eja.2024.127099

Jansen, D.M. 2008. Beschrijving van TIPSTAR: hét simulatiemodel voor groei en productie van zetmeelaardappelen. Nota/ Plant Research International, Plant Research International, Wageningen, Report no. 547. https://edepot.wur.nl/27135

Janssen B.H., 1984. A simple model for calculating decomposition and accumulation of "young" soil organic matter. Plant and Soil 181, 235-265. https://doi.org/10.1007/BF02205588