Precision Ag’s Role in Getting Nitrogen Right For a Better Environment
Scientists can be forgiven for thinking that when they come up with optimized methods for accomplishing some task, end-users will jump at the chance to implement the new ideas simply because they are better. If only it were that simple.
Farmers in particular have a tendency to stick with the tried-and-true. For precision agriculture to have a greater impact in the fields, research findings must be presented with the farmer’s perspective always in mind. Whether the farmer has a small plot in Africa or a large operation in Iowa, he can always do things smarter and more efficiently. Nitrogen management offers a perfect example of an area in which farmers must do better.
In many places around the world, farmers have a legal duty to ensure their use of the land does not result in an excessive amount of nitrates leaching into the groundwater. The European Commission’s Nitrates Directive, for example, was adopted in 1991.
In response, farmers have leaned on experience to fine-tune their existing management procedures and reduce leaching, but they do not necessarily know the answer to the question of exactly how much of the substance leaches into the groundwater during a cropping season. For them, precision agriculture is not a cure-all. It is a technique that can fill specific and crucial gaps in their knowledge.
Perhaps the biggest gap in the market, from the farmer’s perspective, is the availability of formal decision support tools to help with needs such as nitrogen management. These flexible tools would incorporate all the excellent research that has been done on yield monitoring, variable-rate application of inputs and zone management in a coherent, easy-to-use package.
Such a toolset would be inherently adaptable to the practical needs of the individual farmer, which is important because no two farms are the same. Adaptability and practicality remain the key to securing the buy-in of end users.
Farmers often have an easier time justifying the purchase of a new tractor or combine than, say, a drone, an array of field sensors or a software package. After all, the value of heavy machinery is well established. How much benefit can be had from analytical tools? Quite a bit, it turns out.
Whether the purchase of any particular analytical tool makes economic sense is a question best answered by the tools themselves. Sensors are an integral component of yield monitors that measure field performance against revenue, ensuring that farmers see that the smarter, more accurate decisions they make have an impact on the bottom line. Properly implemented, sensor technologies are critical to achieving the data density required to ensure farmers have the economically actionable intelligence they need to improve their management practices.
Farmers are let down when they turn to methods like the Normalized Difference Vegetation Index (NDVI) to determine how much nitrogen they should use on their crops. NDVI determines the density of green in a field, which serves as a useful measure of plant health. Plant health is not the same as nitrogen stress, which is why relying on NDVI for variable rate nitrogen application can create undesirable results.
For instance, a field might show poor yields because of insufficient irrigation or insect stress. Applying more nitrogen will not improve the situation. Rather, it will waste the farmer’s resources and contribute to environmental degradation. Farmers need remote sensing tools that offer a more direct measurement of nitrogen stress than NDVI can provide.
This is critical, because the days of indiscriminately bombarding fields with nitrogen are coming to an end, to be replaced with more precise application of fertilizer. Precision agriculture lets the farmer know how much is enough, but coming up with the answer depends on having an appropriate array of crop canopy sensors that enable growers to escape old-fashioned methods of basing today’s nitrogen application on how much was applied last year.
True precision requires real-time analysis, as the right amount is always in flux. Dynamic factors such as soil moisture levels and weather conditions constantly alter a plant’s nitrogen uptake. When combined with the technique of in-field reference strips, remote sensors arm growers with the data they need to more precisely apply nitrogen. If the output of a field matches the yield of the reference strip, no more nitrogen is needed. Conversely, if output is down in comparison, more nitrogen may be needed.
The most obvious payoff of advanced nitrogen optimization tools is the extra bushels at harvest time. For the farmer struggling to make it through depressed commodity prices, big savings on input costs are also hard to ignore. Yet the greatest benefit of all would be measured in the environment.
Failure to apply nitrogen with precision causes significant harm. As much as nitrogen delivers a massive boost to corn yield, it has an even greater effect in promoting algae growth when fertilizer runoff hits a stream or lake.
Eutrophication is the term used to describe the resulting overabundance of nutrients in a body of water. While plankton and algae feast upon the bounty of nitrates, they also multiply rapidly and disrupt the ecosystem’s balance. The algae that die end up consuming enough of the available oxygen that native fish suffocate.
In addition to this, nitrates making their way into the water supply raise significant human health concerns. The Environmental Protection Agency considers levels above 10 parts per million a hazard to drinking water, reflecting an elevated risk of various forms of cancer. The situation is so serious in central Iowa that farmers have their livelihoods at risk in a lawsuit filed by the Des Moines Water Works over runoff.
The best way to get ahead of any such developments is to get nitrogen right in the first place, which is to say, by applying no more nitrogen than the plant can absorb. The Iowa Soybean Association keeps track of the performance of nitrogen sensing in the field. Most farmers are reporting savings of between $10 and $20 per acre in reduced fertilizer costs, meaning that growers recoup the cost of sensors within a year or two in many cases
Byrum is Senior R&D and Strategic Marketing Executive in Life Sciences – Global Product Development, Innovation and Delivery at Syngenta. Byrum will present the session, “Solving Big Problems: Innovation Through Open Collaboration” at the PrecisionAg Vision Conference on October 19. For more information visit www.precisionagvision.com