SSM-iCrop2
SSM-iCrop2 is a simpler version of SSM crop models which is suitable for undertaking large scale estimation of crop production of diverse crop species, especially in assessing food availability and climate change impacts. The model was adapted to simulate a large number of plant species including orchard species and perennial forages. Simplification of some methods employed in the original model was necessary to deal with limited data availability for some of the plant species to be simulated. The model requires limited, readily available input information. The simulations account for plant phenology, leaf area development and senescence, dry matter accumulation, yield formation, and soil water balance in a daily time step. Parameterization of the model for new crops/cultivars is easy and straight-forward. The resultant model (SSM-iCrop2) was parameterized and tested for more than 30 crop species of Iran using numerous field experiments. Tests showed the model was robust in the predictions of crop yield and water use. Root mean square of error as percentage of observed mean for yield was 18% for grain field crops, 14% for non-grain crops 14% for vegetables and 28% for fruit trees.
This latest version (v.20230220) of SSM-iCrop2 calculates green and blue soil water balance components including green and blue soil evaporation and plant transpiration and green and blue water footprints based on Hoekstra (2019: Green-blue water accounting in a soil water balance. Adv. Water Resour. 129: 112-117 ). However, it should be noted that the model does not calculate capillary rise that may be important where the water table is high (less than 2 m). The output can be found in the “YearlyO” sheet of the model file in columns AY to BD.
Reference:
Soltani, A., Alimagham, S.M., Nehbandani, A., Torabi, B., Zeinali, E., Zand, E., Ghassemi, S., …. Vadez, V., van Ittersum, M.K., Sinclair, T.R., 2020. SSM-iCrop2: A simple model for diverse crop species over large areas. Agric. Syst. 182: 102855
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SSM-iCrop2N is a version of SSM-iCrop2 that can simulate soil and plant N balances. It has some other capabilities, for example, irrigation and N fertilization scenarios can be defined in different ways. However, we have not tested the model although the approaches used have already been tested in our SSM models.
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A python version of the model is available at: https://github.com/zackaryleady/Py_SSM_iCrop2