Salinity Mapping for Precision Variable Rate Fertilizer Application

The incidence of salinity affected areas in irrigated fields results in restricted crop growth in the saline areas. If fertilizer applications are a constant rate blanket application over the field, the saline affected areas receive a greater rate of nutrients than the crop can use. This can lead to a build up of excess nutrients, especially N and P.

IPNI-2014-CAN-AB33

01 Mar 2014

Project Description


Project Description:
The incidence of salinity affected areas in irrigated fields results in restricted crop growth in the saline areas. If fertilizer applications are a constant rate blanket application over the field, the saline affected areas receive a greater rate of nutrients than the crop can use. This can lead to a build up of excess nutrients, especially N and P.
The purpose of the project is to use salinity level designated management zones to variable rate apply nutrients on the cropped fields. It is planned to delineate at least four variable rate fertilizer rate management zones in the mapped area. For example as follows:
    1. non-saline zone, 0 to 0.5 milliSiemens per cm (mS/cm), receiving full rate fertilizer applications
    2. low level salinity zone, 0.5 to 2 mS/cm, receiving a 0.75 rate of fertilizer compared to the zone 1,
    3. moderate salinity zone,2 to 4 mS/cm, receiving 0.5 rate of fertilizer compared to zone 1
    4. very saline zone, > 4 mS/cm, not receiving any fertilizer.
This applied research project is coordinated by Mr. Dick Puurveen of the University of Alberta – Renewable Resources Department. A Veris™ salinity mapping unit was used on an irrigated farm, Clear Lake Colony, near Stavely, AB, on October 29 through to November 1, 2014. The field mapping done included 1400 irrigated acres of the 10,000 acre farm. Using Global Position System (GPS) tagging, salinity levels were recorded in the area mapped. The Clear Lake Colony, Field Manager Mr. Frank Waldner supplied an auto-steer equipped tractor, and an operator for the project. Salinity mapping was done on 50 ft wide transects over the mapped area. The Versis™ salinity mapping unit used for this project was loaned by the Government of Alberta – Alberta Innovates Department, Manager Mr. Arnold Janz.
The landscape and soils of the Clear Lake Colony farm are described as a veneer to blanket of Sandy Loam to Loamy Sand glacial fluvial deposits overlying Clay Loam textured glacial till. It is rolling to undulating in slope. The soils have been developed for irrigation for the last 15 years. The lower landscape areas are subject to mild to very saline levels of salinity. It is hoped to variable rate fertilizer applications to more closely apply rates of nutrients close to crop use. In the severely saline areas this will probably result in no application of fertilizer.
The specific project to be funded will include the following activities:
    1. The raw Veris™ data will be reviewed and confirmed accurate by Veris.
    2. Dick Puurveen and a graduate student/s will use Veris Soil Viewer software to develop geo-corrected salinity maps of the fields mapped.
    3. Soil sampling will be done in early spring of 2015 to ground truth salinity levels of soils within the delineated zones of salinity.
    4. The Clear Lake Colony will hire the Farmers Edge precision farming consulting company to develop fertilizer rate recipe maps for use with their variable rate equipped planting and fertilization unit. These fertilizer rate maps will be used while planting and fertilizing. There will be both check (no fertilizer) strips, and full rate blanket fertilizer rate strips designed into selected fields. This is standard protocol by Farmers Edge when working with farm customers.
    5. Yield maps will be generated for the mapped variable rate applied fields.
    6. A final report will be completed in the fall of 2015.