I remember the co-op's trucks roaring across our farm's soybean fields in the fall, leaving a dusty trail of dry fertilizer behind. The following spring, one of my chores was filling the starter fertilizer boxes on the corn planter. Occasionally, Dad would have anhydrous custom-applied to the cornfields. After that, he put the crop in the hands of Mother Nature to bring home a bin buster.
Back then, nitrogen was relatively cheap and water quality concerns from displaced nutrients were mostly an afterthought of environmentalists and regulators.
Times have changed when it comes to managing fertilizer and that's a good thing. Fertilizer programs today are far more sophisticated than when I was growing up on the Cottonwood Valley Dairy Farm. Technology has spearheaded new thinking and new application tools on how and when nitrogen, phosphorus, potassium and micronutrients are applied.
Nitrogen now is one of the costliest inputs in corn production. Nitrogen use averages 18% and 13% of the variable costs in a corn/corn and corn/soybean rotation, respectively, sometimes more. Growers must use nitrogen efficiently to maximize its value. Keeping nutrients in the field -- out of rivers, streams, and water supplies -- is now at the forefront of state and federal regulatory agencies.
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Maximizing returns on every dollar invested in the crop is top of mind for growers as they prepare for the 2016 growing season. It was on our minds, too, when we began preparing a special series called Finesse Field Fertility. We understand developing the right fertilizer program is challenging. It requires you to minimize nitrogen losses by applying the appropriate rate, and timing applications to coincide with peak uptake by the crop. At the same time, you must ensure potential yield isn't limited by insufficient nitrogen uptake throughout the entire period of crop growth.
The balancing act starts with having the right road map, in this case, soil samples. Pulling accurate information from every field is the foundation for every crop fertility decision. Whether you use a simple manual soil probe or a high-tech automated soil sampler, you need a true picture of a field's fertility profile.
In-season application of nitrogen is also becoming more common as growers analyze more layers of data from their fields. That requires a different set of tests, but like soil samples, accuracy is paramount.
Some growers who apply nitrogen in-season have turned to crop sensors mounted on the application rig. The sensors work by analyzing reflected light to determine the amount of chlorophyll in crop leaves. This is indicative of nitrogen content and/or need. Readings are fed into crop growth and fertilizer rate algorithms to provide the right prescription of nitrogen applied on-the-go at variable rates across the field.
Finally, all the technology and data at your fingertips to calculate nutrient needs won't translate into higher yields unless your soils are healthy. Many growers are turning to cover crops to help build more productive soils. Their goal is to increase organic matter content, and in turn, soil water-holding capacity. In addition, they're integrating nitrogen-producing plants into their cover-crop mixes for added benefits.
The days of applying the standard 1 to 1.5 pounds of nitrogen for every bushel of corn are over. Economics and environmental concerns require we do something better. Keep reading this series, appearing in top stories this week and also available in our Recent Features area, as we continue to post articles that highlight new practices and the growers using them.
Gregg Hillyer can be reached at firstname.lastname@example.org
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