- Author: Michael D Cahn
Cool season vegetable production requires significant inputs of water and nitrogen (N) fertilizer to maximize yield and quality. Proposed changes in water quality regulations on the Central Coast and higher fertilizer prices in recent years have prompted grower interest in increasing efficiency of nitrogen fertilizer use in lettuce. By improving water management and matching nitrogen applications to the uptake pattern of the crop, growers could potentially reduce fertilizer use and address water quality concerns.
Two tools available, the quick nitrate soil test and weather-based irrigation scheduling, have been shown to help lettuce producers better manage water and fertilizer nitrogen. Trials we conducted in commercial fields have demonstrated that soil nitrate concentrations greater than 20 ppm NO3-N, are sufficient to maximize crop production. In addition, we have shown that evapotranspiration data available from the California Irrigation Management and Information system (CIMIS), can be used to accurately estimate the appropriate volume of water to apply to meet crop needs and minimize potential leaching losses of nitrate-N.
Both the quick nitrate soil test and weather based irrigation scheduling require more management time for growers to implement in their farming operations. The quick nitrate soil test entails collecting a representative soil sample in the field, extracting the sample, and calculations to estimate the concentration of soil nitrate. Weather based irrigation scheduling requires calculating crop evapotranspiration (ET) from CIMIS reference ET data and a crop coefficient corresponding to the developmental stage of the lettuce crop. In addition, information on the soil type and irrigation system is needed to determine the optimal irrigation interval and run-time. With multiple fields and ranches to track throughout the season, customizing water and fertilizer for individual fields could become a significant cost for growers.
CropManage is an online database-driven tool that assists growers and farm managers in determining water and nitrogen fertilizer applications on a field-by-field basis. The software automates steps required to calculate crop water needs from CIMIS ET data, and estimates fertilizer N needs for lettuce using quick N test data and models of crop N uptake. The web application also helps growers track irrigation schedules and nitrogen fertilizer applications on multiple fields and allows users from the same farming operations to view and share data.
The software was developed by UC Cooperative Extension and is free to use, and can be accessed at: https://ucanr.edu/cropmanage The application can be accessed with a web browser using a smart phone, laptop, or tablet computer. The tool uses a secure login procedure so that only individuals with permission can view and/or edit water and nitrogen fertilizer records of a particular farming operation.
CropManage was designed to be as intuitive as possible for growers and farm managers to use. Once logged on, users can view a list of ranches/farms that they have permission to access. By following the hyperlink for an individual ranch, a user can view a list of all active plantings associated with the ranch. Each planting has a summary of the ranch name, lettuce type, planting configuration as well as soil type, field name and planting and harvest dates:
Tables summarizing soil nitrate tests, fertilizer applications, and irrigation schedule are shown for each planting:
Getting started with CropManage.
There are three steps to begin using CropManage:
- Obtain account username and password by following the “create new account link” at the bottom of the login page and completing the instructions. Read and accept UC privacy and data security policy to continue.
- Set up a new ranch in CropManage by selecting “new ranch” at the bottom of the ranch list page, or request to be assigned to an existing ranch/farm. All users are automatically assigned full access to a ranch named "UCCE Ranch" so that they can try out CropManage. To add a new ranch to CropManage, we recommend that you use the online form. One can also download the excel ranch template from the import/export options link. Fill in the required information and email the template to firstname.lastname@example.org so that it can be uploaded into CropManage. For more details on setting up a new ranch, click here.
- Set up new plantings in fields within a ranch. Select “new planting” at the bottom of the current planting list and fill in or select required information.
If you have interest to learn more about using CropManage, please contact Michael Cahn (831) 759-7377 or Barry Farrara (831) 759-7365.
Note: CropManage is still in the development stage, so new features will be added in the upcoming months. Recommendations are currently specific for romaine and iceberg lettuce production. We plan to expand this tool to a wider group of cool season vegetables in the upcoming months as funding permits.