Tackle Field Variability with Strategic Inputs

March 8, 2018 02:46 PM

Field preparation, planting and in-season management would sure be a lot easier if all your fields were the same, right? The truth is, managing field variability is a big challenge for most farmers. How can you best match up what’s needed for each zone of your field with what you actually apply, and even get field variability to work in your favor?

Variable-rate planting and applications can help you allocate in-field investments more precisely and place inputs where they will be most effective. You may be able to optimize yield potential by applying fewer inputs in more marginal acres and ramping them up in areas of the field with greater promise.

Here are some tips on creating variable-rate prescriptions to use this season.

1. Have the right equipment.
As long as you have a planter with a hydraulic drive and the capability to adjust planting rates on the fly, you can do variable-rate planting and applications. Make sure your planter system can effectively manage a prescription and then execute it. If you have an older planter without this capability, talk with your trusted advisor about the feasibility of investing in a newer planter. Because it is a big expenditure, be sure it is the right one for you and what you want to accomplish.

2. Don’t go it alone.
There are some online tools that allow you to create your own variable-rate prescriptions. I would not recommend using them. There are many factors that go into creating a variable-rate prescription, and the ability to accurately create and effectively apply them is most effective with the help of your trusted advisor, whether that’s your agronomist, retail seller or ag technology specialist (or all three). You already have enough to do, so keep in mind that staying current with the latest technology is a big part of their jobs.

Reach out to the professionals you work with to take the lead. Talk with them about your goals, your opportunities and your current capabilities. Then they can work on creating a prescription and save you precious time. 

3. Place seed properly.
A professionally prepared field prescription will help you place the right seed in the right spot at the right rate. Essentially, the prescription is a map your planter monitor reads that lets it know which zones of your fields will get what rates of seed.

Many ag technology programs allow your agronomist to create zones for different areas, with each aspect of your field comprising a “layer” of the prescription map. Those layers can include variables such as soil type, historical yield data and previous fertility rates. It also includes your unique knowledge of your fields. Taken together, these factors go into creating a map that will let your planter know what plant populations to use in different areas of the field to achieve optimal yield and return on investment outcomes.

4. Know the pop per crop.
Because of their distinct physiologies, most crops require different amounts of seed to realize optimal yield potential. For corn, it makes sense to increase planting populations on higher-producing areas to try to improve ear quality and decrease rates on poorer-performing areas.

With soybeans, planting rates can often be reduced on more productive acres and increased in lower-producing areas. Soybean plants that grow too tall can have issues with lodging, particularly if their populations are too high on productive soils. Backing off on populations allows soybean plants to branch out and add more pods rather than just working on getting tall with fewer pods.


5. Apply nutrients as required.
Soil sampling is a good first step for any fertility program, and using historical yield data, in-season imagery or other available satellite imagery helps increase prescription accuracy. Work with your trusted advisor to determine optimal soil test timing.

Proper nutrient management can help you budget more appropriately, thereby optimizing your return on investment potential. For example, you may have an area in your field that requires more lime than another. It doesn’t make sense to put the same rate of lime on both places.

Placing the proper amount of lime where it is needed and cutting back or eliminating it from areas that won’t provide you with better return potential helps you allot your nutrient budget more accurately. You can also use variable-rate prescriptions to allocate other inputs, such as fungicide applications.

Don’t forget that your soil has only so much nutrient-holding capacity. Unused, excess nutrients don’t do your soil, your crop, the environment or your pocketbook any good.

Case in point
I recently worked with a farmer who had sections of a corn field that weren’t performing as well as the rest of the field. So instead of straight-rate seeding the field, we created zones around the trouble areas to drop population in the prescription and reduce competition. One of these problem areas was a low, gravely 14-acre stretch along a railroad track, where we dropped the population 4,000 seeds per acre from the average.

We were able to maximize the yield in this area from a historical average of 115 bushels per acre to around 150 bushels per acre. The area was still low-performing, but we reduced the seed input for those 14 acres and brought the yield up. To the farmer, it was a win-win.

Bottom line: Make your inputs count
No two fields are created equal. The goal of any variable-rate prescription is to improve ROI potential by prioritizing input allocations. Talk with your agronomist today about how you can partner to create the prescriptions that work best with your field variability and your budget.

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