Advice on watering wheat, peas

Press, Volume CXII, Issue 33094, 8 December 1972, Page 8

Advice on watering wheat, peas

In five years at Winchmore irrigation research station Aotea wheat irrigated only once in a season when the soil moisture fell to the 10 per cent level yielded only three bushels to the acre less than the same variety receiving three or four irrigations in a season at regular intervals.

In giving this information to farmers at a field day at the station last week, Mr E. G. Drewitt said that their recommendation would consequently be that wheat should only be given one irrigation at the 10 per cent soil moisture level. The same result, he added, would be achieved if the

watering was applied when the wheat was in the booting stage. That was just before the wheat came into ear and generally about mid-November. If a farmer wanted to go for the extra bushels obtained with the extra waterings, then Mr Drewitt said that irrigation would have to start a little earlier and the two additional irrigations would need to be given at about three weekly intervals. In this case irrigation would need to start in early November with the second treatment being given at the end of November and the third in early December. But a decision as to whether three irrigations were to be given rather than one would need to be made early as in their

experience where two irrigations had been given at widely spaced intervals in three out of four seasons they had obtained a poorer result than from one irrigation at the booting stage. Another reason why watering should be kept to a minimum was that with more waterings the grain tended to be of a lower nutritional value. Last season he said the new Kopara wheat had been included in their trials and the indications were that it was likely to perform rather similarly to Aotea, in that it would do better at the low rate of irrigation, whereas Arawa tended to yield a little higher at heavier rates of watering. To date Mr Drewitt said that they had had no

response to nitrogen when applied to Aotea wheat sown out of pasture and while there was a suggestion that there was a response with a second wheat crop in succession this had not reached an economic level. And he added that if nitrogen was used under dry soil conditions without water there was just as likely to be a depression in yield.

Discussing irrigation of viner peas on the Limore stony silt loam soil at Winchmore, Dr R. Stoker said that their recommendations were that during the vegetative stage of growth water should be applied if it got very dry, but from flowering through to harvest the soil needed to be kept moist all through this period. On their soil type he said that two to three irrigations might be needed in an average year.