Nitrogen Use Efficiency (NUE)
December 2022
The optimum rate of nitrogen for a crop will depend on many variables, one of which is the efficiency of use. This can vary greatly depending on several factors, including the weather conditions around application, the state and health of the crop and particularly its root system, the product being applied, and the availability of other nutrients.
The greater the NUE, the more nitrogen is taken up by the crop and therefore the returns on the investment are likely to be greater, whilst there will be less ‘wasted’ nitrogen that is susceptible to loss from the field potentially causing environmental harm.
Trials carried out by Yara in 2018 looked at the comparative NUE of winter wheat with differing nutritional regimes. The findings showed that balanced crop nutrition, where the proper supply of macronutrients and micronutrients in a balanced ratio supplied throughout the growth of the crop, resulted in the highest level of NUE and the highest yields.
Although nitrogen is likely to give the greatest economic return on investment, even at the significantly higher prices, yield increases will not be gained, and therefore investment wasted, if nitrogen is not the most limiting factor. Where nitrogen is supplied to a crop that has insufficient available potash, the nitrogen use efficiency will be reduced as the return on the investment in nitrogen wated.
More efficient nitrogen management, through the appropriate use of all other nutrients, can help to improve returns, sequester more carbon, and reduce the emissions of greenhouse gasses such as N2O.