|Tuesday, June 01|
Adoption of Precision Agriculture in Alberta Irrigation with Implications for Sustainability
* Lorraine Nicol, University of Lethbridge, Canada
Christopher Nicol, Canada
To fulfill world-wide food requirements in the future, agriculture production will need to increase significantly. But given the stress agriculture places on the environment, production must also be sustainable. A new suite of agricultural technologies, commonly referred to as ‘precision agriculture’, has been found to improve farming efficiency and environmental sustainability. Precision agriculture allows fields to be deconstructed into small precise section, based on variability, so inputs can be more precisely applied compared to conventional methods which treat fields as uniform. This study focuses on the potential for adoption of precision agriculture on irrigation farms in southern Alberta. Through irrigation, southern Alberta has become amongst the most fertile and productive agricultural regions in Canada. It is also recognized for its entrepreneurial and progressive farm culture and practices. This economic and cultural environment may provide fertile ground for the adoption of precision agriculture technologies. A survey of farmers in three major irrigation districts in the region finds relatively high rates of adoption. On-farm results include improved crop yields and crop quality as well as reduced irrigation water, fertilizer, pesticides and herbicides use. Further, adopters plan on continuing adoption of precision agriculture technologies in the future. Therefore, precision agriculture on irrigation farms in southern Alberta holds significant promise of contributing to the dual objective of increased production through sustainable agriculture.
Enhancing Yield and Nutrient Use Efficiency of Crops under Subsurface Drip Fertigation in Southern Alberta
* Rezvan Karimi, Lethbridge College, Canada
Willemijn Appels, Canada
In addition to improving water use efficiency, subsurface drip irrigation can be used for nutrient management during the growing season. A field experiment was conducted to evaluate the effect of drip fertigation at a commercial farm near the community of Lomond, Alberta, Canada with a Clay loam soil. A first (banding) application of fertilizer, 175 kg N ha-1, 45 kg P2O5 ha-1, 23 kg K2O ha-1 and 23 kg S ha-1 in 2019 and 90 kg N ha-1, 103 kg P2O5 ha-1, 27 kg K2O ha-1 in 2020, was performed at seeding, based on soil tests performed in the fall of 2018 and 2019. Additional fertilizer, 67 kg N ha-1 and 17 kg P ha-1 in 2019 and 45 kg N ha-1 and 17 kg P ha-1 in 2020, was applied during the growing season. The field experiment was a completely randomized design with 5 treatments and 3 replicates. Treatments included early application of ammonium nitrate as the N source (N), Essential Phos as the P source (P), N+P, split application of N (SN), late application of N (LN) and control. Biomass samples were collected four times: before fertigation, two times mid-season after fertigation, and at harvest. In each zone, biomass samples were taken in eight randomly-selected areas using a 0.25 m2 quadrant for a total area of 2 m2. At harvest, plant samples were taken from an area of 4.0 m2 to reduce variability in the biomass data. The plant material was dried in an oven (60°C) for one week. After threshing, the grain was weighed, and yield was calculated. The weights of pods, beans and leaves were determined separately and the number of the pods for each zone were counted. Total N and P uptake were determined on oven-dry samples. Results of the effects of the various fertigation strategies on the yield and nutrient use efficiency will be presented.
How precise can precision irrigation be?
* Willemijn Appels, Lethbridge College, Canada
"Current developments in irrigated agriculture aim to address spatial patterns of plant water needs and soil water availability. In this study, soil moisture dynamics and yields were observed in irrigated potato fields in southern Alberta. We compared differences in soil moisture in various landscape features and soil textures to small-scale variability around each monitoring point. The magnitude of soil moisture variability was compared to the accuracy of the irrigation schedules. The two years of observations featured years that were relatively low in rainfall. The observations were complemented with simulations of the APSIM model to investigate the stability of the results in wetter growing seasons."
Optimizing pivot irrigation with the right sprinkler package
* Jonathan Holt, Utah State University, Canada
Most pivot sprinkler packages in Canada and the western United States are classified as mid-elevation sprinkler application (MESA). Evaluations of this style of sprinkler package have shown they are about 78% efficient at getting the water that leaves the nozzles into the root zone. Studies on low elevation spray application (LESA), low energy precision application (LEPA), and mobile drip irrigation (MDI) have shown efficiency improvements of up to 19% from MESA. Because of increasing pressure on agricultural water, we set out to evaluate something that few studies have: could the more efficient pivot packages maintain crop yield and quality, while applying irrigation at a reduced rate? To evaluate the possibility, eight site-years of data were collected at four Utah farms from 2018 to 2020. Crop yield and quality responses to full and reduced rates of each system were tested in alfalfa, corn, and small grains. Soil water tension was also measured. Data showed that the advanced systems were sometimes able to maintain yield and quality while applying 15 to 25% less water, yet there were several instances where MESA performed better than the advanced systems. This led us to conclude that there is not one system that will have the best results all the time, but tailoring the sprinkler package to the field characteristics is where optimization with these packages can occur. This presentation will discuss the results and observations used to create the Utah State University Extension publication, “Guide to Irrigation Sprinkler Packages for Pivots and Laterals.”
Crop coefficient development for canola in Saskatchewan
* Hakibu Tanko, Afgriculture and Agri-Food Canada, Canada
Canola is the most extensively grown crop under irrigation in Saskatchewan. However, crop coefficient (Kc) values required to estimate daily water use by the crop have not been developed in the Province. An on-farm field study was conducted in 2019 near Outlook SK to develop local crop coefficients for canola in Saskatchewan. Locally developed crop coefficients would enable better canola evapotranspiration estimation needed for more efficient irrigation management to increase yield, improve crop quality, and reduce costs associated with excess moisture. A Bowen Ratio Energy Balance System (BREBS) was used in the field to determine evapotranspiration. The FAO56 Penman Montieth equation was used to calculate grass-reference (ETo) and alfalfa-reference evapotranspiration (ETr) using data from meteorological station at Canada-Saskatchewan Irrigation Diversification Centre (CSIDC), Outlook SK. Seasonal evapotranspiration obtained for canola from May 25 to September 8 was 399 mm. The daily evapotranspiration for canola ranged from 0.4 to 7.2 mm per day with a mean value of 4.0 mm per day. The canola crop coefficients based on grass-reference (Kco) and alfalfa-reference (Kcr) values obtained ranged from 0.10 to 1.38 and 0.07 to 1.19, respectively. Mean Kco values of 0.27, 0.89, 1.14, and 0.77 were obtained for the initial, development, mid, and late season crop stages while Kcr values were 0.21, 0.72, 0.90 and 0.55, respectively in 2019. Using multiple regression analysis, third-order polynomial equations were developed for estimating Kco and Kcr as functions of cumulative growing degree days. The study will be conducted again in 2021 growing season to further refine the crop coefficient values for Saskatchewan. "