Fertilizer nitrogen use efficiency in irrigated cotton cropping systems

Irrigated cotton in Australia is mainly grown on heavy textured clay soils which are prone to waterlogging and loss of significant amounts of nitrogen to the atmosphere.

This study investigated fertilizer nitrogen use efficiency (fNUE) on commercial cotton farms. Fertilizer NUE was consistently low, with on average 47% of the applied fertiliser lost over the season and only 17% of the N taken up by the crop derived from fertiliser. The results demonstrate that currently nitrogen fertiliser is not used efficiently and that cotton growers could significantly reduce N fertiliser inputs without any negative impact on lint yield.