There is a new version of the app that allows you to get a quick snapshot of the water status on all your fields. Go to the Apple App Store or Google Play store and download the newest version of the CropX app
Scheduling Your Last Irrigation
If you’ve look closely at your sum graph on your commercial corn fields, you will notice that we lowered our refill line now that the crop is past pollination and moving towards maturity. We are often asked why and how we do that. There are some very sound agronomic principles behind finishing the season with a 65% depleted profile (UNL Recommendation). One is that a dry soil will compact less during the harvest. Also, if the soil is dry at black layer and we start to get rains during harvest you can get back into the field much quicker than those fields that entered Black Layer with a full profile. Drier soils also allow for more freezing and thawing in the winter, helping improve soil structure. And, one of the most important reasons is applying water that is not needed, COSTS MONEY.
All that being said, achieving that 65% depletion goal and making sure we have enough water to get us to black layer requires some careful agronomic planning. Because of the tall corn canopy and the dropped leaves on the soil surface, evaporation is very limited. To dry down the soil profile, we need to rely on the plants to extract moisture. And since little ET takes place after Black Layer we must dry it down before physiological maturity.
To do that we first must estimate when Black Layer will happen. We use charts like the one below to help. Here you see the projected BL (Black Layer) date (September 14th) of a 113 hybrid planted April 25th in Hall County. Of course, the two critical pieces of information here are hybrid maturity and planting date. This is why we are adamant about getting that data into the system early in the season.
Once we have an estimate of maturity date and we also calculate the days we have before BL happens and compare it to the chart above. In the chart below you see that at soft dough we would normally have 30 days to maturity.
Then we look at water needs between current stage of growth and black layer. For example in the chart if we are at the dough stage (most fields will probably be there next week) we would need 7.5” of water to finish.
We then compare the current profile storage (see below) to see how much additional water will be needed to get us to maturity. Here we have 16.7” but because we are above Field Capacity that will drain back to full at 16.3”. 16.3” – 10.6” (our refill point of 65% depletion) leaves us with 5.7” available. If our field was at dough stage (7.5” needed to finish) we would be 1.5” short. But that is assuming we will get no rain in the next 30 days.
However, our normal rainfall for this time period is more than two inches (see chart below) so if we have normal weather (what ever that is) we probably would not need to irrigate this field again before BL.
As always, if you have any questions ask:

Probe Management Team
Nick Lammers 308-380-0509 / Matt Maloney 308-380-1200
Curt Maloney 308-380-5761/ Jenie Maloney 308-380-3900
Soil Moisture Probe Optimization Program
Full-service soil moisture monitoring program. From the leaders in precision irrigation management!

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