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.
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.
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?”
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.
