New Zealand Journal of Crop and Horticultural Science abstracts

Wheat (Triticum aestivum) response to micronutrients (Mn, Cu, Zn, B) in Canterbury, New Zealand

D. Curtin
R. J. Martin
C. L. Scott

New Zealand Institute for Crop & Food Research
Private Bag 4704
Christchurch, New Zealand
email: curtind@crop.cri.nz

Abstract Trials were carried out at 20 sites in 2004–05 and at three sites in 2006–07 to determine if micronutrient application is required to maximise wheat yields in Canterbury, New Zealand. Micronutrients were applied at recommended rates as solid fertiliser (zinc (Zn) and boron (B)), foliar spray (manganese (Mn)), or both (copper (Cu)). Foliar treatments increased Cu and Mn in vegetative tissue, but not in grain. Soil-applied CuSO4 had little or no effect on plant Cu. Sodium borate (2.3 kg B/ha) increased plant B by an average of 68% at mid-late tillering (Zadoks growth stage 22–29). Zn (4.4 kg/ha as ZnSO4) gave small improvements in plant Zn (generally <20%). In 2004–05, there was no yield response to the treatments, even though about half the sites were below the suggested critical soil thresholds for Cu and Zn. In 2006–07, two sites showed yield responses (up to 0.9 t/ha) to Mn, but not to Zn or Cu. The soil EDTA (ethylenediaminetetraacetic acid) test was generally a poor indicator of wheat micronutrient status. The critical tissue Mn concentration to achieve 95% of maximum yield was estimated at 13 mg/kg at ear emergence. Our results suggest that wheat crops with >12 mg Zn/kg at mid-late tillering or >10 mg Zn/kg at ear emergence do not respond to applied Zn. Crops with >2 mg Cu/kg at mid-late tillering were not responsive to Cu.

Keywords manganese;copper; zinc; boron; wheat; fertilisation; tissue testing; diagnosis of micronutrient deficiency

New Zealand Journal of Crop and Horticultural Science, 2008, Vol. 36: 169–181
0014–0671/08/3603–0169 © The Royal Society of New Zealand 2008
H08006; Online publication date 11 August 2008
Received 29 January 2008; accepted 20 June 2008

PDF file of entire paper: Print-quality (332K) | screen-quality (264K)