Yesterday, the Des Moines Register reported on continued concerns over nitrogen runoff into the Mississippi River from corn country. The article (click here) pointed out that much of the solution is coming from decreased runoff from small, family operations.
Environmental activists want more regulation, even suggesting the state set limits on fertilizer applications. The Register article reassures farmers that any discussion of setting arbitrary limits on nutrient applications would be 'dead on arrival' at the State Capitol.
There are a number of things growers can do to minimize nutrient loss due to runoff.
A no-till strategy with cover crops is the best way to combat nutrient runoff. Iowa State University released data last month showing nitrogen runoff can be cut by up to 31% by following corn with rye. Hay, oats, and barley are also effective -- anything that holds the soil, keeping nutrient infused soil particles from making it downriver.
Maintain buffer strips between fields and streams, and if livestock is using a creek or stream as a water source, move feedbunks and shelters as far away from the water as possible. This will help to keep solid waste out of the water system.
Apply as much of your fertilizer in the post emergence phase as possible. Fall fertilizer applications are at greater risk for runoff than spring applications, but keep in mind that if the whole state of Iowa decides to apply nutrient in the spring, shortages may push prices higher. ISU does point out, however, that changing from fall application to spring application only reduces nitrate runoff by 6%.
When using manure for fertilizer, consider injecting rather than spreading. Laying the manure on the surface of the dirt can lead to runoff in the event of a post application rain event. Injecting manure will assist nitrification and hinder nutrient motility while recharging your soil more effectively than surface applications.
Application rates must be carefully considered. After this year's spotty yields -- even within individual fields -- consider using GPS related tools to avoid over-application, and target areas of high yield in your plots, where nitrogen carryover is likely minimal.
Along with fertilizer runoff, atrazine runoff is also a concern. Keep in mind that applying more than recommended amounts of atrazine to crops for weed control will not translate into higher effectiveness. Always follow label directions, and consult with your distributor with any questions you may have before applying.
As always, your Inputs Monitor recommends soil testing before making any decisions regarding fertilizer application. Minimizing runoff is not only good for the nation's water supply and environment -- efficient applications will save time and money on the farm. In addition, reducing the environmental footprint of agriculture will insulate growers from the threat of over-regulation.