The 2017 growing season started with warm dry planting conditions, followed by significant rain delays in May in many parts of the state, and a summer of intermittent weeks of hot and cool temperatures. The net result is that crops may mature over a longer period than usual this fall. Fortunately, the following procedure for making end-of-season irrigation decisions is based on crop maturity stage rather than the calendar.
I have worked with irrigation management for almost 20 years. Today most farmers are doing a better job than when I started, however many still tend to over apply water -- leaving room for improvement. That left me wondering “Why” and “What could help more farmers apply the optimal amount of irrigation water?”
Factors such as the amount of water a soil can hold, the amount of water a crop will use until it reaches maturity, and the maximum allowable soil water depletion should be considered when deciding the last few irrigations of the season.
Extension recommendations for calculating the amount of nitrate-nitrogen in irrigation water and optimal timing of applications to reduce the cost of nitrogen inputs in irrigated corn.
In a dry spring like 2025, early irrigation may be needed — but applying too much water too soon risks losing nitrogen and rainfall storage. Learn how soil moisture monitoring and timing can protect yields and inputs.
The key to knowing the correct setting for a chemigation pump is to first determine how many acres per hour the pivot will cover at the desired irrigation application depth or rate.
Scheduling the last few irrigations of the season deserves extra attention because the goal is not only to focus on keeping the crop wet enough to produce optimal yields, but also on using up stored soil water. Leaving the field a little drier at the end of the season will save irrigation costs, decrease leaching losses, improve soil conditions for harvest traffic, and save water for future years. Growers also don't want to miss out on capturing off-season precipitation.
