Tuesday, July 26, 2011

Sustainable corn.

Image from Iowa State University to Science Daily

An interesting article came up in my RSS feeds recently.  According to work done at Iowa State University, corn production might just become a little more sustainable.  Mind you, I feel that there is a little more to this story than what you might (or might not) read about in the papers.

Poa pretensis alongside corn seedlings.  Source.
This work experimented with the planting of perennial cover crops (something to keep soil in place when the land is not producing cash or food crops) between rows of corn in a study that lasted three years.  The work revealed that Kentucky bluegrass (aka poa pretensis) was the best fit for the job.  This may be the case for several reasons.  I have no doubt that the plant itself fits well.  It has a low profile compared to corn, meaning it will provide little to no competition for sunlight, but farmers are also familiar with the plant and how to manage it.  The grass is found in lawns across North America, and it would seem that in this case familiarity has not bred contempt.

The foremost conclusion of this study, however, was that crop yields would not suffer should it be grown among rows of bluegrass.  This is important to the story, because farmers would refuse to utilise a method which would somehow cripple crop yields.  Luckily, the yields were the same when compared to a control crop (one grown using conventional methods nearby).  However, there are other reasons to be excited for these results.  I ask that you refrain from sipping brandy before the next paragraph, and hang onto your monocles.

Corn is a notoriously hungry and thirsty plant.  As I have previously discussed, corn requires comparatively high fertiliser inputs.  The benefits of a perennial cover crop have a lot to do with the stabilisation of the soil.  There is less exposed ground to bake in the sun, so water requirements become lower.  Further, with less soil exposed to wind and rain, the erosion of soil and the leaching of fertilisers are also retarded.  It is also worth noting that the study included two years which farmers described as "funny".  Flooding was commonplace in 2008, and 2009 saw the coolest July on record.  Both situations would doubtless challenge crops, but the corn managed to survive.

For the record, soil erosion may become more important in time.  Though I cannot lend credence to the claims as I have not researched them, I have heard rumblings that the price of top soil may rise in years to come as we deplete our conventional sources of the stuff.  Soil is created over millions of years by the wearing down of rocks, and humans have yet to develop a synthetic route for its synthesis.

Bearing what I have said in mind, it would seem that the benefits of this sort of agricultural method might become more and more obvious in years to come.  Perhaps in drought years the grass will allow for more efficient water use.  Further, it may also prove that farmers in the future will require less fertiliser and additional topsoil to replace that which was lost in wind and rain.  This would all lower the costs (both thermodynamic and financial) of growing corn, and thus feeding humanity.  I am pleased to see this work, and wonder if it could be extended to other crops as well.