Don't apply urea to snow

Dave Franzen, soil specialist with North Dakota State University's Extension Service, wrote a clever fertilizer-themed version of Charles Dicken's "A Christmas Carol." It's a fun read, with an important message. The gist is that farmers are still applying urea on to snow, and its a big waste of time and money. The urea runs off in the spring before the soil thaws and can absorb it. NDSU studies show a huge drop in wheat yield and protein levels when urea is applied on snow, versus applications into soil before freeze up in the fall or in the spring after the soils have thawed.

Watch for fertilizer best practices

With all the talk of greenhouse gas (GHG) mitigation at Copenhagen and everywhere else — with carbon-regulated Alberta leading the way — farmers will be encouraged (maybe financially rewarded) to pay closer attention to best management practices to reduce fertilizer losses and make more efficient use of their fertilizer investment. This is a good thing.

But it seems we're short on research to clearly show just what practices are best. A report from the International Fertilizer Industry Association, based in Paris, makes these points:

—There is debate regarding the mitigation potential of tillage measures. This is because assessing the net impact on GHG emissions requires comparing the impacts on both soil organic carbon, which is often biased by field measurements taken only in the top 30 cm of the soil profile, and nitrous oxide (N2O) emissions, which are highly variable over time. The balance of evidence does, however,point to a net benefit for suitable soil types, although more research may still aid our understanding in this area. Reducing tillage also gives indirect savings in terms of reducing on-farm fuel use and associated emissions.

—Agronomy measures are perhaps the most difficult mitigation practices to assess at present. Using catch crops, legumes and particular types of crop rotations could potentially reduce GHG emissions per hectare of cropland but can also impact on yields, potentially requiring additional land to be cultivated at great cost in terms of soil organic carbon losses. For example, the global warming potential of an intensive continuous corn crop may be 2-3 times higher, on a per hectare basis, than that of a conventionally-tilled corn-wheat-soybean rotati on, but produce only 63% of the net GHG emissions when compared on the basis of CO2 -equivalent per calorie of food yield. Therefore, more work is needed to compare net GHG emissions from different cropping systems over the long term and on a per unit of production basis.

Considering the source, IFA does lean toward a solution that favours getting more yield out of the same land rather than clearing more land to feed the growing population. That means more fertilizer use, and better yet, improved fertilizer use efficiency. Not applying urea onto to snow and having it wash away in spring, as NDSU reminds us, is a simple step in that direction.