WHEAT AND WEATHER

Evening Post, Volume CVII, Issue 150, 29 June 1929, Page 7

WHEAT AND WEATHER

QUESTION OF YIELD

INTERESTING RESEARCH

Last year, during harvest time in Canterbury, the Meteorological Office made arrangements to broadcast at noon each day a special weather forecast for farmers. Although this innovation was the subject ( of much appreciative comment, last harvest season happened to be one of the best ob record, and so there was not. as much need for these forecasts as there would be in some seasons. Similar forecasts for applo growers were also much appreciated. But it is not altogether upon the harvesting of the wheat crop that the weather plays such an important part: meteorological factors also affect the wheat yield. To what extent this is the case Dr. E. Kidson, Director of Meteorological Services, has been investigating, the wheat yields at Lincoln College since the year 1883 being used for correlation with the meteorological records for the same period. In order to cariy out such an investigation satisfactorily, says Dr. Kidson, one requires to have a homogeneous set of records of wheat yield covering a very long period. The yields should be unaffected by changes in methods of cultivation, manuring, seed varieties, or other extraneous influences. Should such changes have intervened, the-vields should be corrected for their effects and so reduced to a uniform standard. Complete and homogeneous meteorological records for the corresponding period are, of course, equally essential. Unfortunately, there are numerous breaks in the meteorological record, and the growth of trees had, by 1927, very seriously affected the site of the meteorological station. Wind and sunshine would be the two elements most affected, bnt it is probable- that there were smaller influences' on temperature and rainfall. It would appear from the records collected by Dr. Kidson that winter condition's have only a slight influence on the yield, the most important period being from October to February, and especially November to January. Next, any factor leading to increased dryness is favourable to a good yield when it occurs in the winter months and unfavourable when it occurs in the spring and summer months. A special effect is the adverse influence of rainfall in February. This is no doubt duo to losses in harvesting caused by the beating-down oi' the plants and the falling of wheat from the ears. March conditions, as. would be expected, appear to have little influence on the crop. The tentative conclusions drawn from the investigations so far made aro: — (1) The weather variations in winter are responsible for only very slight variations in the wheat yield. Cool and dry conditions are probably favourable. (2) In spring and summer warm and moist conditions are favourable, especially'" in the growing period, but considerable losses may be caused by heavy rain in February. (3) There seems to be little- prospect of making a. useful crop forecast any considerable time before harvest, since conditions in the period immediately preceding the cutting of the crop have the greatest influence on the yield.