SPASMO models the transport of water, microbes and solutes through soils integrating variables such as climate, soil, water uptake by plants in relation to farm and orchard practices, and any other factors affecting environmental process and plant production.
SPASMO, which has been in continuous development for over 20 years, has been used by six Regional Councils for allocation of irrigation water. It has also been used in a large number of projects within other Regional Councils, commercial clients and researchers.
The SPASMO computer model considers water, solute (e.g. nitrogen and phosphorus), and microbial (e.g. viruses and bacteria) transport through a 1-dimensional soil profile. The soil water balance is calculated by considering the inputs (rainfall and irrigation) and losses (plant uptake, evaporation, runoff and drainage) of water from the soil profile.
The model includes components to predict the carbon, nitrogen and phosphorus budget of the soil. These components allow for a calculation of plant growth and uptake of both N and P, various exchange and transformation processes that occur in the soil and aerial environment, recycling of nutrients and organic material to the soil biomass, and the addition of surface applied fertiliser and/or effluent to the land.
The filtering capacity of the soil with regard to micro-organisms is modelled using an attachment-detachment model with inactivation (i.e. die-off) of microbes. SPASMO is currently used as an 'in house‘ code within Plant and Food Research. Models are tailored according to the individual needs of the end user. End users are councils at regional and district levels as well as consultants, and the model accounts for a range of on-farm and within-orchard practices. For example, consultants may use a SPASMO framework when analysing irrigation to determine the need to irrigate a given crop in the next week, month or period until harvesting, on a particular soil given the weather history at the site and the current weather-cycle conditions.
SPASMO incorporates data from several databases including weather and soil databases and from information such as material safety data sheets for pesticides which record the holding times in soils. Because a unique SPASMO simulation is created for individual client, and their farm and orchard practices, the data sources used are appropriate for the question and for the time period specified. SPASMO is now being used as the software engine for online, real-time irrigation scheduling, and it has also been modified to act as a water footprint calculator for primary products.
|State of Development||Closed Beta|
|Current Development Activity||As needed|
|Outcome Areas||Environmental, Economic|
|Subdomains||Contaminant Losses, Water Yield, Crop/Farm Systems, Pesticide leaching|
|Intended End Users||In-house only|
|Temporal Extents||Dependent on weather data, Years, Decades, Centuries|
|Steady State or Dynamic||Dynamic|
|Level of Integration||Economic, Environmental|
|Key Input Data||Land Use, Rainfall, Temperature, Potential Evaporation|
|Input Data Formats||CSV|
|Key Output Data||Micro-economic data, Runoff, Drainage leaching, gaseous loss|
|Output Data Formats||CSV|
|Open/Closed Source||Closed Source|
|Licence Type||No Licence|
|Not available for non-commercial use|
|Not available for commercial use|
|Operating Systems||MS Windows|
|User Interface||Other (please specify)|
|Ease of Use||Difficult Difficult because of the complex structure and large range input data files required.|
|Use in Policy Process||Plan (Policy Formulation), Do (Policy Implementation), Review (Issue Identification)|
N/A but there are several publications with some parts of the model described
|Support||Meta-model to end-users available|
|Users Forum||Not Available|
|Methods included for calibration and validation||Extensive calibration and validation; see references|
|Methods included for managing uncertainty||Outputs are given as probability distributions.|
|Analytical Techniques||Input/output, GIS, System dynamics|
|Keywords||irrigation, nutrient leaching, soil, climate, plant production|
|Linkages to other Models|
Rosen MR, Reeves RR, Green SR, Clothier BE, and Ironside N, 2003. Prediction of Groundwater Nitrate Contamination after Closure of an Unlined Sheep Feedlot. Vadose Zone Journal 3, 1990-2006.
Green SR and Clothier BE 1995. Root-water uptake by kiwifruit vines following partial wetting of the rootzone. Plant and Soil 173:317-328.
Green SR, Kirkham MB, and Clothier BE 2006b. Root uptake and transpiration: from measurements and models to sustainable irrigation. Agricultural Water Management 86:165-176
Green, S.R., B.E. Clothier, C. van den Dijssel, M. Deurer and P. Davidson, 2008. Measurement and modelling the stress response of grapevines to soil-water deficits in their rootzones. Chapter 15, In Soil Science Society America Monograph “Modeling the response of crops to limited water: Recent advances in understanding and modeling water stress effects on plant growth processes”, L. Ahuja et al.[Eds] Chapter 12, pp 357-386
Nitrate contamination of groundwater by a sheep feedlot in Hawke's Bay, New Zealand led to closure of the feedlot in 1998.