30 June 1998
Potential wheat yield without soil N testing

Question

WHAT shoot count should I aim for in shoots/m2 to reach potential yield of my wheat if I do not carry out soil nitrogen testing?

Response

Dick Neale, technical manager, H L Hutchinson

Answer

TO capture as much as 1t/ha extra yield, growers should be aiming for early drilling dates, but sowing rates should be adjusted – downwards – accordingly. Then in February you can apply nitrogen confident that the crop isnt rank and running away with you. A rate of 150 seeds/m2, for instance, would make a lot of growers splutter, but that should be a typical target.

However, early drilling will demand a careful choice of variety. Weak-strawed varieties – those rated 6 or below for standing power, such as Hussar or Reaper – should be avoided for the first 15-20 days of September.

Lower seed rates also mean that each individual plant receives a proportionately higher dose of fungicide, and the microclimate in a denser crop is more conducive to septoria development. In company trials this year, septoria was much more apparent in the bottom of wheat drilled at 312 seeds/m2 than at 112 seeds/m2.