Impact of enhanced-efficiency fertilisers on potato productivity in a temperate cropping system

Nitrification inhibitors are intended to improve the productivity of agricultural crops, 19 however there is limited data available on the efficacy of this approach in potato crop 20 production. A field experiment was carried out in temperate Australia to compare the 21 effect of standard commercial fertiliser nitrogen (N) management with fertiliser treated 22 with two nitrification inhibitors, 3,4-dimethylpyrazole phosphate (DMPP) and 1H-1,2,4-23 triazole and 3-methylpyrazole (3MP+TZ) on potato productivity and soil N dynamics for 24 three irrigation regimes. Despite evidence of increased soil ammonium (NH+4 ) concentrations in the DMPP and 3MP+TZ treatments, crop yield and quality parameters 26 (tuber number, average tuber size, potato specific gravity, three tuber size classes and 27 grade yields) were similar across treatments. Further, DMPP and 3MP+TZ treatments did 28 not reduce either the concentration or the flux of nitrate leached. These findings suggest 29 that further research into the agronomic benefits of nitrification inhibitors for potatoes 30 grown in cool temperate regions is needed.