There are many available tools to aid production agriculture, with most utilizing some sort of technology. But I think one of the most valuable tools for me, as an agronomist, is a well-calibrated yield map.
Using a yield map to develop high-, medium- and low-yielding management zones will pay great dividends, and disburse those dividends quickly.
Management zones are the blueprints for managing nutrients for profit, as well as for environmental stewardship. Once these zones are established, they will repeat through various weather cycles, sometimes alternating between high and low yield, but usually still represented.
Yield zones are a better depiction of the soil types in your fields rather than a digitized soils map. The soil survey says one soil type is present on one side of the line, and another soil type on the other side.
This is not how it happens at field level. There are actually transition zones as one soil type blends into another, and good yield maps will show these areas. These areas will need to be managed differently.
More than likely, with today’s progressive farmers, fertility will not be the limiting factor or the reason yields vary within a field. Water infiltration and drainage is probably the No. 1 factor, and it’s good to know if that’s a problem in your fields.
If it’s a problem, you can decide if it can be improved or if you can manage it more economically than with a “blanket” fertility approach.
The next most limiting factor I see is lime. Management by yield zones has helped me fine tune lime applications better than any other evaluation of the soils.
Lime is the “operating system” of nutrient management, similar to the operating system in your computer. You may be able to squeak by with an out-dated system, but operation will be sluggish and efficiency poor. Lime is like good oil in the crankcase, essential for top performance.
With today’s costs of nitrogen, phosphorus and potassium, you really need the soil to operate efficiently.
Are you getting 60% effectiveness from your applied phosphorus, or just 30%? Does your crop find 25% of the potassium in your soil, or are you in the fast lane to profitability with a 70% capture rate? Can you produce a root system that recovers 90% of the nitrogen available to it, or does it struggle by only utilizing 40%?
Not only does lime create the environment for optimum chemical reactions that are beneficial to nutrient uptake, it also affects soil structure and microbial life by creating a desirable “live soil.”
Depending on your soil composition, calcium and magnesium can have a profound effect on water infiltration rates. Does water run in, or run off? Does soil life thrive after rain, or does it take a step backward due to poor infiltration of water and, in turn, poor air movement into and out of the soil?
Do nutrients tie up after a rain, or in the case of nitrogen become lost forever? Or is your crop able to keep on pace and capture the nutrients it needs, even under stressful weather conditions?
Soil science is complicated and is not a one-size-fits-all program. Yield monitors and in-field plots are helping us prove new practices for agriculture on a farm-by-farm basis.
Farmers need to think outside the box today and not accept Agronomy 101 rules just because that’s the way it was done 30 years ago. Things have changed. There’s a lot at risk and a “prove-it” approach is well warranted.
My next post will dig deeper into this subject and focus more on precision ag tools, so stay tuned.