Ventura County Resource Conservation District
Funding for this project has been provided in full or in part by the United States Environmental Protection Agency and the State Water Resources Control Board under the Federal Nonpoint Source Pollution Control Program (Clean Water Act Section 319). The contents of this document do not necessarily reflect the views and policies of the foregoing, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.
Interactive Irrigation Management to Reduce the Leaching of Nitrogen (IIMRLN)
Program Purpose Nitrogen from non-point sources, including agricultural activities, are contributing to pollutant loadings throughout Ventura County. To address this, VCRCD developed a project called IIMRLN (Interactive Irrigation Management to Reduce the Leaching of Nitrogen) with the specific goal of reducing the amount of nitrogen discharged below the root zone of agricultural crops.
NIM Station Description A NIM station is a discrete unit comprised of a suite of data collection devices located in an agricultural field. The data collection devices associated with each NIM station includes
- two soil moisture sensors for water infiltration depth
- a pressure switch for irrigation frequency
- an atmometer for evapotranspiration
- a rain gauge for on-site rainfall
- a lysimeter for soil water sampling
- a data logger to store in-field data
- a cellular modem for real-time data access
- a solar panel for power.
Program Objectives The project’s objectives include the placement of nutrient and irrigation management technologies within fields, working with growers to track and interpret this data, and, if nitrogen leaching is observed, continue working with them to implement irrigation and nutrient management measures to reduce the amount of nitrogen in their leachate.
NIM Station Purpose NIM station components (soil moisture sensors, pressure switch, and atmometer) will be networked to a cellular modem so the data from these components can be accessed by both the grower and RCD staff via an online data management portal. This will allow RCD staff to collaborate with the grower in near-real time on irrigation related issues and provide a common platform around which irrigation and nutrient scheduling discussions and, ultimately, decisions will occur.
Unlike these three networked components, the NIM station rain gauge and lysimeter will be logged and recorded by RCD staff during regularly scheduled site visits or during triggered sampling events. Normally, data from these units will be collected regularly, be it weekly, bi-weekly, or monthly based on weather and agronomic cycle or need - for example, rain gauge readings will be collected following rain events. Similarly, lysimeter sampling will be triggered whenever the lowest soil moisture sensor indicates the soil below the root zone is near saturation and that nitrogen leaching may be occurring.
Program Approach RCD will provide growers with interactive Nutrient and Irrigation Management (NIM) stations (Figure 1). NIM stations will provide irrigation-related data in a cloud-based format allowing that information to be shared and accessed remotely via an online portal. This will enable RCD staff to work collaboratively with cooperating growers to address irrigation and nutrient management issues. By sharing, viewing, and discussing this information, RCD staff can explain trends, identify issues, discuss remedies, and take action with growers in near-real time. This approach is designed to build grower confidence in the technology, with the goal being that the grower actively engages with the technology when making irrigation management decisions. Similarly, these interactive NIM stations will also provide RCD staff and project’s grower cooperators a way to monitor potential and actual nitrogen leaching. By tracking soil moisture, RCD staff and growers can see if irrigation or rainfall has initiated leaching, whereupon the on-site lysimeter will be sampled to determine the amount of nitrogen present in the soil leachate.
Program Goals By tracking soil moisture, RCD staff and growers can see if irrigation or rainfall has initiated leaching, whereupon the on-site lysimeter will be sampled to determine the amount of nitrogen present in the soil leachate. By coupling together soil moisture and soil nitrate data, 1) a clear connection between irrigation, rainfall, and nutrient management will be established, and 2) nitrogen losses can be quantified and remedies (either through irrigation management, nutrient budgeting, or some other management measure) can be applied and their efficacy tracked.
Interested in participating? Contact Jamie Whiteford at firstname.lastname@example.org to sign up or submit an interest form by clicking here!
Figure 1: Nutrient and irrigation management (NIM) station descriptive diagram.