Woods End worked with Highmoor Exp. Station to observe corn growth in plots where plow-down sod produced nigh N-mineralization. Some of the plots took up excess N and stored it as nitrate.

A corn nitrogen study presented at the 2013 Agronomy Society meeting in Palm Beach examined soil tests to indicate potential nitrogen not measured by conventional soil tests. An anomolous result raised interesting questions about excessive nitrogen uptake, also known as “luxury consumption”. The 2 year field plot study conducted by Will Brinton and Mark Hutchinson (University of Maine) at the Highmoor Experiment Station was intended to observe effects of compost on sweet corn yield. Instead a unexpected result revealed some corn plots absorbed a quantity of nitrogen far in excess of that needed to efficiently attain a high yield. The explanation was that some areas of the field had prior permanent sod which when plowed down to enlarge the plots produced a burst of mineralized-N. The plants packed the extra N away in the form of high tissue nitrate. Luxury consumption by plants when encountered with excessive nutrients is curious, since by absorbing unnecessary nitrogen, plants are removing it from the soil, but not using it efficiently for yield gain. “We know that corn silage containing excessive nitrate can be toxic for animals, but here we have to ask more generally what the pathway of the excess N will be”. If corn stover is left in the field the excess nitrogen could become fertilizer for the next season – or lead to climate harmful loss as N2O. “Unfortunately, routine soil testing would not see any of this”. This could lead to reccomending too much N the following season. Brinton and Hutchinson showed that normal corn stalk tissue contained about 250 ppm nitrate but plants from sod-plow down plots had over 1% (10,000 ppm). The slide show with lecture recording will be viewable at the digital library.