BETTER FARMING WITH NEW CHEMICALS

Press, Volume XCVII, Issue 28701, 26 September 1958, Page 8 (Supplement)

BETTER FARMING WITH NEW CHEMICALS

By

L. J. MATTHEWS,

Weeds Research Officer, Department of Agriculture.

The problem of weeds in crops dates back to the history of man. With a swing from fat lamb farming to more cropping, efficient control of weeds in crops again assumes importance.

Burning and oversowing, and grazing and oversowing allowed nassella tussock to increase. The weedkillers, TCA and dalapon, have offered the one ray of hope in control of nassella tussock.

These chemicals effectively control seedlings or kill parent plants. This is not the problem. The major problem is that of replacing the destroyed nassella tussock with desirable competitive vegetation.

The same applies to sweetbrier. Rabbits caused a plant vacuum in the high country. The rabbit was reduced and man did not have the knowledge to fill the plant vacuum with desirable vegetation. Sweetbrier is filling this gap. It can be killed with chemicals, but the problem of replacing it in low rainfall areas has not been solved.

Ten years ago a yellow field of wild turnip or a sea of fathen or Californian thistle were common .sights. Today such sights are regarded as poor farm management. Modern weedkillers are capable of most weeds from cereals and lucerne. The farmer has no need to delay sowing of his lucerne or new pasture because of weeds. Potatoes were once regarded as a cleaning crop for weeds, now almost any crop can be regarded as a cleaning crop. Twitch-like grass in orchards and vineyards or asparagus beds can now be eliminated. Man has' no need to cultivate for weed control alone, in fact this can be regarded as poor farm 1

management. Nor is he so dependent on fine weather for harvesting of small seeds. Such has been the progress in development of modern weedkillers. Only one-third of the agricultural land in New .Zealand is capable of being developed by ploughing or giant discing. The remaining area cannot be fully utilised because of the difficulty of introducing the correct species to take advantage of such practices as aerial topdressing. If the barrier could be broken between land that can be cultivated and land than can not, then the agricultural potential of New Zealand would be greatly increased. Cultivation essentially destroys existing competition and prepares a seed bed. Weedkillers meet the first requirement more efficiently than cultivation, and the dead litter in most areas forms a suitable seed bed. Where direct comparisons have been made, the chemical method of introducing pastures and some crops has compared favourably with normal practices of cultivation. This remains a challenge for the future.