Start | Index | Overview • PREV | UP | NEXT The routines for this SimComponent are taken from Lintul 3 (Shibu et al. 2010). Nitrogen promotes growth and increases biomass production of plants. It is an essential part of all proteins, enzymes and metabolic processes involved in the synthesis and transfer of energy. Nitrogen is a part of chlorophyll which is responsible for photosynthesis. The rate of N uptake of crops is highly variable during crop development and between years and sites.
NitrogenDand calculates the N demands of the different crop organs (NDEML fpr leaves, NDEMS for stems, NDEMR for roots, and NDEMSO for the storage organs), the distribution of the absorbed N to the plant organs and the translocation of nitrogen from leaves, stem and roots to the storage organs.
Daily nitrogen demand of leaves, stems and roots is calculated based on desirable maximum amount of nitrogen in the respective plant organ at a given day and the amount of nitorgen already present in the respective plant organ. For the nitrogen demand in leaves this is e.g.
\[ \begin{eqnarray} NdemandLeaves = (NMaxConcentrationLeaves \cdot WeightGreenLeaves) - AmountNitrogenLeaves \end{eqnarray} \]where NdemandLeaves is the amount of N required for maximum growth of leaves (g N m^-2), `NMaxConcentrationLeaves`is the maximum N concentration in leaves at a given development stage (DVS), `WeightGreenLeaves`is the dry matter of leaves at a given day and `AmountNitrogenLeaves`is the actual amount of N in the leaves (g N m-2).
N.B. In Lintul-FAST the Ndemand of the plant organs was divided by the coefficient TimeCoefficientNUptakeMassflow, but this was not the case in Lintul4 and Lintul5
The sum of the NDemand of all organs is the potential amount of nitrogen to be taken up by the roots from the soil in non-legumes. For legumes, the potential N demand i reduced by a user defined percentage called cNAbsorptionReduction.
The nitrogen taken up by the crop from the soil (including the N fixed by legumes) is distributed proportionally among the plant organs according to their share in the total N demand at a given day. After sowing and until a user defined development stage (GrainToCropDevStage), there is an additional user-defined daily nitrogen supply (GrainToCropDailyNitrogen in g N m^-2 d^-1) from the N reserves in the seeds (GrainToCropMaxNitrogen`in g N m^-2). `GrainToCropMaxNitrogen can be calculated by the user by multiplying the seed weight in g per m2 with the N concentration. After flowering, the daily N demand of the storage organs (rateofChangeNitrogenContentsStorageOrgans in g N m-2) is calculated. Beased on the N demand of storage organs the translocateable nitrogen in leaves, stems and roots is transferred proportionally to the storage organs according to their share in the total translocateable N as for example from leaves:
\[ \begin{eqnarray} rateNTranslocatedLeaves = rateofChangeNitrogenContentsStorageOrgans\cdot \frac{ATNLV}{ATN} \end{eqnarray} \]where rateNTranslocatedLeaves is the translocated N from leaves to storage organs at a given day (g N m^-2 d^-1), ATNLV (in g N m^-2) is the translocateable amount of N in leaves and ATN (in g N m^-2) is the total amount of translocateable N in leaves, stems and roots.
However, the N demand of the storage organs and the resulting N translocation `rateofChangeNitrogenContentsStorageOrgans`is moderated by dividing the translocateable N by a time constant of translocation (TranslocationNTimeCoefficient, set at 10 days as default):
\[ \begin{eqnarray} NSUPSO = \frac{ATN}{TranslocationNTimeCoefficient} \end{eqnarray} \]where NSUPSO is the maximum amount of translocateable N in g N m^-2 at a given day.
Nitrogen is calculated based on the relation between the N concentration in photosynthetic active organs (leaves and stems) compared to the optimum N concentration at a given day. Thus, in a first step the optimum N concentration (NOPTMR in g g^-1) is calculated by adding up the optimum amounts of N in leaves and stems and dividing them by the actual dry matter. The optimum amounts of N in plant organs are calculated based on the optimal N concentrations in leaves and stems (NOPTLV and NOPTST) which are a user-defined fraction (NoptimalFraction) of the maximum N concentrations (NMAXLV`and `NMAXST in g g^-1). By default the NoptimalFraction is set to 1.0, so optimal and maximal concentrations are identical.
Then the actual N concentration in stems and leaves is calculated (NFGMR in g g^-1) and reduced by the concentration of residual N in stems and leaves (NRMR in g g^-1) at a given day. The Nitrogen Nutrition Index (NNI) is then calculated according to Shibu et al. (2003) as
\[ \begin{eqnarray} NitrogenNutritionIndex = \frac{NFGMR-NRMRi}{NOPTMR-NRMR} \end{eqnarray} \]This routine computes the N losses due to the death of leaves, roots and stems. The daily N losses in the three organs (rateNLossLeaves in g N m^-2) are calculated as the residual N concentrations in the three organs (e.g. NonTranslocateableResidualNConcentrationsLeaves in leaves in g g^-1) times their death rates (RateofChangeWeightDeadLeaves for leaves and DRRT for roots in g m^-2 d^-1).
Finally the amount of nitrogen in the three plant organs (e.g. r_rateofChangeNitrogenContentLeaves in g N m-2 d-1) at the end of a given day is updated as follows
\[ \begin{eqnarray} rateofChangeNitrogenContentLeaves = (rateNuptakeLeaves + dailyNitrogenFixed) - rateNTranslocatedLeaves - rateNLossLeaves \end{eqnarray} \]where rateNuptakeLeaves`and `dailyNitrogenFixed (in g N m^-2 d^-1) are the proportion of fixed and soil derived N which goes to the leaves and rateNTranslocatedLeaves and aux_rateNLossLeaves (in g N m^-2 d^-1) are the daily losses of N from leaves due to translocation to the storage organs or due to leaf death.
References:
| Content Type | Name | Description | Data Type | Unit | Min Value | Max Value | Default Value |
|---|---|---|---|---|---|---|---|
| constant | cANLVI | Initial amount of N in the leaves at emergence | DOUBLE | g/g | 0.001 | 20.0 | 0.0135 |
| constant | cANRTI | Initial amount of N in the roots emergence | DOUBLE | g/g | 0.001 | 20.0 | 0.0016 |
| constant | cANSTI | Initial amount of N in the stems at emergence | DOUBLE | g/g | 0.001 | 20.0 | 0.006 |
| constant | cDELT | Time step in days | DOUBLE | d | 0.0 | 20.0 | 1.0 |
| constant | cDevelopmentStageNUptakeStops | Development stage (DVS) at which N uptake from the soil stops | DOUBLE | 1 | 0.001 | 20.0 | 1.0 |
| constant | cFRTTB | Fractions Table Root | DOUBLEARRAY | 1 | 0.0 | 20.0 | - |
| constant | cFractionMaxNConcentrationRootsNConcentrationLeaves | Crop-specific factor to derive maximum N concentration in roots from tabulated maximum N concentration in leaves | DOUBLE | 1 | 0.001 | 20.0 | 0.37 |
| constant | cFractionMaxNConcentrationStemNConcentrationLeaves | Crop-specific factor to derive maximum N concentration in stem from tabulated maximum N concentration in leaves | DOUBLE | 1 | 0.001 | 20.0 | 0.5 |
| constant | cGrainToCropDailyNitrogen | Daily amount of nitrogen that is supplied from the seeds to the roots | DOUBLE | g/m2 | - | - | 0.02 |
| constant | cGrainToCropDevStage | DevStage up to which nitrogen is supplied from seeds to the crop | DOUBLE | 1 | 0.0 | 2.0 | 0.0 |
| constant | cGrainToCropMaxNitrogen | Maximal amount of nitrogen that is supplied from the seeds to the roots | DOUBLE | g/m2 | - | - | 0.4 |
| constant | cNAbsorptionReduction | Reduction of the N absorption | DOUBLEARRAY | 1 | 0.0 | 20.0 | 0.0 0.0 0.2 0.0 1.0 0.0 |
| constant | cNMaxConcentrationLeaves | Tabulated maximum N concentration in leaves in relation to crop development stage (DVS) | DOUBLEARRAY | g/g | 0.0 | 20.0 | 0.0 0.06 0.4 0.05 0.7 0.04 1.0 0.03 2.0 0.014 2.1 0.002 |
| constant | cNMaxConcentrationStorageOrgans | Crop specific maximum N concentration in storage organs | DOUBLE | g/g | 0.001 | 20.0 | 0.02 |
| constant | cNonTranslocateableResidualNConcentrationsLeaves | Residual (minimum) nitrogen in the leaves which is not translocatetable to storage organs | DOUBLE | g/g | 0.001 | 20.0 | 0.004 |
| constant | cNonTranslocateableResidualNConcentrationsRoot | Residual (minimum) nitrogen in the roots which is not translocatetable to storage organs | DOUBLE | g/g | 0.001 | 20.0 | 0.002 |
| constant | cNonTranslocateableResidualNConcentrationsStem | Residual (minimum) nitrogen in the stem which is not translocatetable to storage organs | DOUBLE | g/g | 0.001 | 20.0 | 0.0015 |
| constant | cNoptimalFraction | Fraction of maximum N concentration which is at the lower limit of optimum N concentration (below this N concentration N deficiency will impact RUE, SLA and LAI | DOUBLE | 1 | 0.001 | 20.0 | 1.0 |
| constant | cTimeCoefficientNUptakeMassflow | Coefficient to mimic the time delay of N uptake due to massflow and diffusion (added by Asseng et al. 2002??, no longer used in Lintul5) | DOUBLE | d | 0.001 | 20.0 | 3.0 |
| constant | cTranslocationNTimeCoefficient | Time delay in translocation of nitrogen to storage organs from all other organs | DOUBLE | d | 0.001 | 20.0 | 10.0 |
| input | iCROP | Identifies whether croptype is a legume ('legumes') or not ('not specified') | CHAR | 1 | - | - | |
| input | iDevStage | Index for development stage of crop (DVS) | DOUBLE | 1 | 0.0 | 3.0 | 0.0 |
| input | iDoHarvest | TRUE at harvest day | BOOLEAN | 1 | - | - | false |
| input | iPlantNitrogenUptake | Total Nitrogen uptake by the crop | DOUBLE | g/m2 | 0.0 | 4000.0 | 0.0 |
| input | iRateofChangeWeightDeadLeaves | Change of weight of the dead leaves at day i | DOUBLE | g/m2 | 0.0 | 4000.0 | 0.0 |
| input | iTRANRF | Transpiration Reduction Factor | DOUBLE | 1 | 0.0 | 3.0 | 0.0 |
| input | iWeightGreenLeaves | Total dry weight of green leaves at day i | DOUBLE | g/m2 | 0.0 | 4000.0 | 0.0 |
| input | iWeightRoots | Total dry weight of roots at day i | DOUBLE | g/m2 | 0.0 | 4000.0 | 0.0 |
| input | iWeightStems | Total dry weight of green stems at day i | DOUBLE | g/m2 | 0.0 | 4000.0 | 0.0 |
| input | iWeightStorageOrgans | Total dry weight of storage organs at day i | DOUBLE | g/m2 | 0.0 | 4000.0 | 0.0 |
| input | iWithCrop | TRUE if crop is present | BOOLEAN | 1 | - | - | false |
| state | sAmountNitrogenFixed | Amount in N Fixed from the atmosphere (only in case of legumes, refer to iCrop) | DOUBLE | g/m2 | 0.0 | 40000.0 | 0.0 |
| state | sAmountNitrogenLeaves | N amount in leaves | DOUBLE | g/m2 | -20000.0 | 400000.0 | 0.0 |
| state | sAmountNitrogenRoots | N amount in Roots | DOUBLE | g/m2 | -20000.0 | 40000.0 | 0.0 |
| state | sAmountNitrogenStems | N amount in Stems | DOUBLE | g/m2 | -20000.0 | 40000.0 | 0.0 |
| state | sAmountNitrogenStorageOrgans | N amount in StorageOrgans | DOUBLE | g/m2 | 0.0 | 40000.0 | 0.0 |
| state | sGrainToCropTotalNitrogen | Accumulated amount of nitrogen, that is supplied from the seeds to the crop | DOUBLE | g/m2 | - | - | 0.0 |
| out | NitrogenAbsorbed | Amount of nitrogen absorbed is the sum of N uptake from the soil (iPlantNitrogenUptake) and N fixed from the atmosphere (in the case of legumes) | DOUBLE | g/m2 | 0.0 | 200000.0 | 0.0 |
| out | NitrogenDemandTotal | Total daily nitrogen demand of the crop | DOUBLE | g/m2 | 0.0 | 200000.0 | 0.0 |
| out | NitrogenNutritionIndex | NitrogenNutritionIndex (NNI), if NNI is below 1, then RUE, SLA and LAI are reduced | DOUBLE | 1 | 0.0 | 1.0 | 1.0 |
| out | NitrogenStressIndex | NitrogenStressIndex (inverse of NitrogenNutritionIndex) | DOUBLE | 1 | 0.0 | 1.0 | 0.0 |