USDA/ERS's Take on Nutrient Reduction
Nov 22, 2013
This week marked the 43rd annual North Central Extension-Industry Soil Fertility Conference and most of the research presented revolved around nitrogen and nutrient reduction. This was a tricky year for reducing the flow of N&P because of last year's drought. A lot of nutrient was left in the dry soil and the heavy spring rains washed fall applications -- and some spring nutrient -- out of the soil and down the creek.
USDA/ERS Weighs in --
The topic of nutrient reduction has thus far been presented at the state level and by the Hypoxia Task force and the EPA. But two speakers from USDA's Economic Research Service (ERS) were on hand at the conference and they each talked about nutrient reduction strategies to limit N&P loss from farms. Dan Jaynes from USDA/ERS spoke of a threefold approach to nutrient reduction. Avoid, Control and Trap. Jaynes noted that there are a number of external factors in nutrient runoff including precipitation, acreage to corn, population/food demand, drainage... the list goes on. These are things that contribute to increased nitrogen use which are beyond the control of individual growers.
To combat the external factors, Jaynes suggested three areas for consideration.
Avoid -- This phase looks to improve N management with the use of cover crops, urease inhibitors and a fresh look at the good 'ol 4R's. The most useful part here is the idea that nitrogen applications could be cut on the farm if a greater focus was placed on nitrogen synchronization. This would have growers applying nitrogen to the crop at various points throughout the life of the plant. We already have seen a shift in that direction and Jaynes suggested that with strategically timed applications throughout the lifecycle of the crop, nitrogen efficiency would improve, and amounts of N&P runoff would fall.
Control -- This is drainage water management, but Jaynes highlighted the fact that this would have no impact on yield and would offer little motivation for farmers to change practices.
Trap -- This includes riparian buffers, in-field bio-reactors and increased acreage to wetlands. De-nitrification bio-reactors have been shown in studies to have reduced N&P egress by 65% over the last eight years. The trouble is the addition of bio-reactors would add expense to the operation and specialized equipment in far flung fields, and would add little if any economic benefit.
Jaynes concluded his presentation with an ominous suggestion of three things that growers can do today.
1) Reduce nitrogen applications by 20%.
2) Plant cover crops to salvage N in the off-season.
3) Eliminate fall N applications.
To the good, USDA/ERS expects nutrient reduction to take a number of years before a difference will be noticeable. This gives growers some time to sort through all the suggestions of new management practices against practices already in place. To encourage adoption, projects in the past have offered incentives to participating growers, but when those incentives run out, participation falters.
While the suggestion of eliminating fall N altogether may run contrary to current practices, it is widely known that significant loss occurs during the winter and in some cases, less than half of fall applied nutrient is still there when the spring crop is planted. Much more is known about the life-cycle of crops given the amount of hybrid variability available to growers than in years past and knowing how to place nitrogen when and where uptake is taking place will make a big dent in nutrient runoff, and may lower nitrogen bills.
As the conference went on, the clear theme was increased N utilization, and these researchers recognize that growers will need to see a little bang for their buck before stepping out and trying a new system. In the months ahead look for buzzwords like nitrogen synchronization, and increased accountability when it comes to nutrient reduction.
Still voluntary --
The EPA and USDA/ERS recognize that they need farmers on board with whatever methods they may come up with regarding nutrient reduction, and that works in our favor. The speakers had an appreciation that best management practices are in place for a reason and that growers may be reluctant to risk a crop on a new approach. But if these management practices lead to gains for producers, or even just don't cost anything, adoption rates will be higher.
Dan Schaefer, Director of Nutrient Stewardship for the Illinois CBMP suggested growers, "Manage nitrogen as a system, not as an application."
Split nitrogen applications starting with pre-plant UAN in the spring after winter cover crops would increase synchronization between nitrogen uptake and N applications. According to research presented this week, scattering nitrogen applications across the growing season will help minimize risk of loss to external factors, maintain current yields and send less N&P down the river at no extra cost to growers -- if managed carefully.
This represents a shift for some, but as environmental factors combine with the pursuit of high yielding crops, farmers are given the chance to try these things out voluntarily, and while no-one is currently talking about regulations on the farm, many believe that day will come if nutrient reduction does not become a priority in crop management.