Implementation of the Mississippi Irrigation Scheduling Tool in a Dynamic Web-based Format.

VanRiessen, H., Irby, D., Rice, B., Crumpton, J., Sassenrath, G. F., Schmidt, A. M., & Tagert, M. L. (2013). Implementation of the Mississippi Irrigation Scheduling Tool in a Dynamic Web-based Format. Conference Proceedings of the 2013 ASABE Annual Meeting. Kansas City, MO, USA: ASABE.

The Mississippi Irrigation Scheduling Tool (MIST) has been developed to provide an automated daily calculation of water balance for row crop production. The system has been designed with a three layer approach: Graphical User Interface, processing engine, and database for data storage. The design of the system allows the latest knowledge of crop water use and irrigation scheduling to be implemented into a decision support tool that is readily and continuously accessible to users, with minimal requirements for data collection, data input, software maintenance, data interpretation, and decision development. The system resides on a central server at the Mississippi State University campus and is accessible through common web browser software eliminating the need for software downloads and/or installations by the user. This method streamlines updates of the software package, and eliminates the time required of end-users in maintaining the decision support tools. National databases of soils and weather data are used that maximize the geographical range at which calculations are appropriate while minimizing requirements for users to collect, store, and input data. Specific information on soil hydrology and available water holding capacity are used in determining the Maximum Allowable Depletion (MAD) of the soil water. Weather data (temperature, relative humidity, wind speed and solar radiation), downloaded from state weather center, are used to calculate daily reference evapotranspiration (ETo). Gridded rainfall data from a national weather database are used for calculating the soil available water using the water balance method. Irrigation application amounts and dates are input by the users. The engine calculates reference ETo from the weather data using the modified Penman Monteith equation on a daily basis for each location. Crop ET (ETc) is then calculated from the reference ETo multiplied by the appropriate crop coefficient. The soil water balance is calculated daily for each location. The web-based user interface was implemented using HTML, Java, JSPs, and Javascript. Care must be taken to address incompatibilities between web browsers to ensure pages are displayed correctly. The database stores all input and output data from each user in a MySQL database. Security of the database is maintained through passwords, MD5 encryption, and prepared statements. Prepared statements are used to prevent one of the more common SQL attacks through SQL injections. MD5 checksum is a cryptography-based algorithm that allows the storage of data in a humanly unrecognizable way. The different types of user entities within the interface include: administrator, manager, consultant, company, and user. With each entity there are different permissions for what the entity is allowed to see. For example: a user entity is an accounted created by the company and only has access to the company’s field information. A consultant, given access to a company's account, will be able to see all the company’s farms and field information that are a part of the company. With company permission, consultants can access accounts of multiple companies. After the initial setup of the company’s account, field location information can be entered by uploading shape files or by outlining the field borders with the built-in mapping tool. Because of the complexity of the initial setup of field, well, and irrigation system information, it is anticipated end-users will perform initial system setup in the office. Following setup of field-level information, all access and decisions can be retrieved via any mobile device, greatly improving the accessibility of the decision support tool.