Ontario Grain Farmer February 2021

similar climate. Historically, Michigan farmers have adopted the practices of irrigating field crops more than Ontario farmers, but use the practice for the corn in their rotation, with very little soybean irrigation. Dr. Xu also broke down yields on a county basis and there are clear differences between the regions of Ontario. The modeling shows that southern Ontario (Niagara to Lambton and south) could irrigate corn more frequently as compared to other parts of the province. If we consider operating costs only, irrigation benefits would outweigh the costs in southern Ontario approximately three years out of five by 2070 (depending on the climate scenario). However, this assumes no cost for labour and less than $1.03 in fuel or electricity to pump one acre-inch of water (102.8 m3). Now let us add the capital costs to this economic evaluation. At a fixed cost of $1,200/acre, irrigation would only be profitable for a few counties in only a few years in the more extreme future climate likelihood scenario (C3) for 2020-2070. If equipment costs could be reduced to $550/acre, approximately five – 10 counties could have profitable benefits from irrigation 3% 3% 6% 10% Base C1 C2 C3 Percent of Years with precipitation less than 60% of mean of precipitation Climate Scenario ONTARIO GRAIN FARMER 29 FEBRUARY 2021 continued on page 30 At current costs and with current climate conditions, irrigation is not economically attractive to field crop producers across Ontario. FIGURE 1. EXAMPLE: PROBABILITY OF DRY EVENTS IN LAMBTON COUNTY FOR 2020 – 2070. FOUR CLIMATE SCENARIOS ARE EXPLORED: BASE - HISTORICAL TREND; C1 - RCP 8.5 ; C2 - RCP 8.5 WITH ASSUMED MEDIUM INCREASED RAINFALL VARIABILITY; C3 - RCP 8.5 WITH ASSUMED HIGH INCREASED RAINFALL VARIABILITY. GRAPH COURTESY OF OMAFRA. Example: Probability of Dry Events in Lambton County for 2020 - 2070 • The probability of dry events increases as the variability of precipitation becomes larger. • 500 Monte Carlo draws per year per county under the more extreme climate scenarios. In the later years (2054 to 2070) of this same future climate prediction and at the same equipment cost of $550/acre, the number of counties in the province where irrigation is profitable jumps to 20 (see figure 2). A caution on this, however, if we consider the costs of developing a well or pond water supply (~$60,000) the number of counties where irrigation is profitable drops to less than five.