Soil moisture data and Water Driven Yield Potential support confident decision making.

I was introduced to Crop Intelligence and soil moisture probes in the spring of 2018 by Ryan Hutchison. That fall, I joined South Country Equipment as a Crop Intelligence Agronomist and put two stations on my family farm in SE Saskatchewan for the 2019 season. This was De Roo Family Farms first year using Crop Intelligence, but I knew we could trust the data to push our yields higher. Weather is tricky to predict, but we knew that understanding moisture conditions on the farm was a no brainer for making better decisions.

Once our stations were installed, and the data showed strong positive yield potential on our fields. Adding a top-dress application to our to-do list required some planning to be logistically manageable. We booked product and purchased streamer bars at the end of May to be ready to go in June – no excuses. To make the most of our learning and start to understand how far we can push yields, we set up a replicated trial in a wheat and a canola field.

CANOLA:

We applied nitrogen to the canola field at the 5-leaf stage. The plant stand in the field was 3-4 plants per square foot, a little lower than our target of 6-7, but frost damage and flea beetle feeding caused some early stand reductions. Our Water Driven Yield Potential had a strong positive trend throughout the season and when we streamed UAN on June 24^th. There was a 1-inch rain in the forecast for that afternoon. The 1-inch turned into a ¼-inch, and rest of the rain came 5 days later. We applied 3 rates, 10, 15, 20-gallon UAN per acre to chase 10, 15, 20 bushel per acre yield gain, respectively and replicated 3 times.

The following costs and income are shown on a per acre basis:

All the application rates resulted in a yield increase of 7-8 bushels above the untreated check. All treatments resulted in a net profit. However, the results showed no significant difference when the nitrogen rate was increased from 10 gallons to 15 or 20. A lack of additional yield response above the 10 gallon per acre application rate, confirmed our thinking that other key macronutrients were not in adequate supply to support a significant yield increase. Tissue tests prior to top-dressing suggested the plants did not have adequate phosphorus or potassium uptake to support a 15+ bushel yield bump.

HARD RED SPRING WHEAT:

The wheat trial was top-dressed at the 6 leaf, 2 tiller stage. The plant stand was adequate at 24 plants per square foot. This field did not have a weather station but was located within 2 miles of our canola station. Soil moisture conditions were ideal, and a few timely rain clouds had passed over the field in early June. We estimated that the Water Driven Yield Potential for this field was about 30 bushels positive and top-dressed the same day as the canola trial. We applied 3 rates; 12, 16, and 20 gallons per acre to target 15, 20, and 25 bushel per acre yield gains, and 4 replications.

The following costs and income are shown on a per acre basis:

All top-dressing treatments produced significantly higher wheat yields and protein over the untreated. The treatments did not have a significant difference in yield between each other, but there was a significant difference in protein. Like the canola, all treatments resulted in a net profit. Lack of additional yield increases at 16- and 20-gallon applications may have been influenced by inadequate levels of other key nutrients in the soil and the crop stage at the time of application. The added nitrogen was applied relatively late in the growing season. The crop was well into tillering, where added nitrogen has an increased chance of contributing to protein content than to additional yield.

In all cases, regardless of crop type or rate, and despite the less than ideal rain and plant growth conditions, we saw a positive return on investment. As a result, we have already committed to more in-season nitrogen for the 2020 crop year. These decisions were further informed by our fall soil moisture data, that showed moisture reserves have the potential to support above average yields in 2020, if we receive one or two timely rains. We have also made it a priority to increase the phosphorus and potassium rates in our blends at seeding time to support our higher yield goals. Long term, we are looking into strategies pre-seeding and post-harvest to build fertility in our soils.

What we learned in 2019:

1. Be prepared. Book product early, find nozzles or another application method that works logistically.
2. Learn on your farm. 10 gal/ac is a good target to start and you do not have to commit to the whole farm.
3. Document results. It is not necessary to set up a replicated trial but take the time to measure the effectiveness of any actions taken this year.