Models Available in OpenAg

OpenAg includes two models that run side by side - one for irrigated lands and one for nonirrigated lands. By default, it uses a Positive Mathematical Programming (PMP) (Howitt et al. 2012) model for irrigated lands and it uses a statistical regression model for nonirrigated (rainfall or dryland) agriculture. You may also choose to run a simple linear version of the model for irrigated lands in place of the PMP model. OpenAg runs each model separately for each region where data are available supporting both models and then pools the results together in the application.

Where the PMP model focuses on decisions of land use and water allocation with user-provided price and yield modifications, for nonirrigated lands OpenAg estimates yields while assuming constant land use. Both models output revenues as their primary output, but only the PMP model estimates land use changes. Each model’s capabilities are summarized in the following table:

Model	User inputs	Outputs
Irrigated Lands PMP (Full) Model	Irrigated water availability, land availability, crop price, crop yield, crop area constraints	Land allocation, water allocation, gross revenue
Irrigated Lands Linear (Simple) Model	Irrigated water availability, land availability, crop price, crop yield	Land allocation, water allocation, gross revenue
Nonirrigated Lands Regression Model	Rainfall, crop price	Crop yield, gross revenue

All models produce employment and value add outputs (when configured) through a connection to IMPLAN data.

The nonirrigated lands model is not included for all regions or all model areas - you will know a region includes rainfall data if the region has a slider to adjust rainfall in the web application.

Warning

Note that the nonirrigated lands model does not take into account land availability adjustments, which can cause apparently skewed results for crops with large proportions of unirrigated cropland when making land adjustments.