Ontario Grain Farmer March 2021

Drip systems require filtration units to provide clean water and avoid emitter plugging (Figure 1). Overhead irrigation is based on replacing the amount of water used by the crop after a certain time period, usually every five to 10 days. The overhead irrigation systems that have been successful in Ontario are traveling gun and centre pivot. The traveling gun is the most common irrigation equipment because of its low capital cost and portability to different fields. Traveling guns require significant labour to move and operate; they also have high power/energy requirements. Centre pivots are the equipment of choice for grain farmers in Michigan. They also have low capital costs compared to drip but can be automated and have lower power/energy requirements than traveling guns. Their disadvantage is that they irrigate a circle pattern, so are best suited to a square field. MANAGEMENT In addition to the basic labour requirements of setting up and operating an irrigation system, there are also management choices that need to be made. When should irrigation be started? How much should be applied? A flow meter is an essential component of an irrigation system package. No manager can do a good job without knowing how much water is being used, when, and on what fields. Decision making tools such as soil moisture monitoring probes and/or weather stations are also important for success. Irrigation ensures that the season’s crop inputs are fully optimized for the crop — making efficient use of seeds, fertilizers, crop protectants, fuel, equipment use, and labour. But venturing into irrigation involves a new level of permitting, environmental considerations, and management. The next and final article in this water series will focus on grain farm water management and interactions with ground water. For more information on irrigation see OMAFRA’s on-line resources, videos, and fact sheets at www.omafra.gov.on.ca/english/ engineer/irrigation.htm also see the BMP 26 book “Irrigation Management” which can be ordered free from Service Ontario at www.publications.gov.on.ca/browse- catalogues/livestock/best-management- practice-series/best-management-practices- series-irrigation-management-revised-2004. This article was written with input from Ian McDonald, Trevor Robak, and John Molenhuis from OMAFRA. l continued from page 25 FIGURE 1: TYPES OF FILTRATION UNITS. (TOP TO BOTTOM) DISK FILTER, SAND FILTER, SCREEN FILTER. PHOTOS COURTESY OF OMAFRA.