This report presents the results of an impact assessment of a cluster of nine nutrition research projects funded by the CRDC over the years 2008-2016.

Nutrition is a critical component for profitable agricultural production. Australian cotton producers are heavily reliant on fertiliser inputs to provide crop nutrition, and this typically represents a substantial proportion of overall input costs. Rates, timings, and application methods all need to be optimised, while plant and soil testing methods need to provide information capable of enabling adjustment of these variables under different circumstances. Ongoing nutrition research is required to capitalise on new technologies, adjust current practices to new cultivars and farming systems, and address long-standing knowledge gaps.

In addition to these economic aspects, crop nutrition also has environmental implications in areas including greenhouse gas emissions and water quality.

While the projects in this cluster focused on a wide range of issues, there were two issues of prominence that were addressed. The first was that of nitrogen use efficiency, as growers were applying increasing volumes of nitrogen (N) fertiliser, either due to decreasing NUE or as ‘insurance’ for achieving high yields. The second was that of ongoing depletion of soil reserves of key nutrients, particularly phosphorus (P) and potassium (K).