Assessing soil N availability is complicated enormously by the complexity of the N-cycle.
Over the years, several methods of estimating potentially available N have been suggested. In an
ongoing study, we have been assessing the suitability of a number of these methods for
predicting potential crop response to fertilizer N. In particular, we correlated amino-sugar N
levels to wheat yield across a variable landscape. This relatively new soil N test appears to be
sensitive to changes in organic matter quality as related to landscape position and holds some
promise for assessing potentially available N. The results presented here are preliminary.