Aerial topdressing has been the key to an increase in the productivity of our hill country. Without its development large areas of hill land would no doubt have gone out of production and many farms would have become uneconomic units. The full utilisation of greater soil fertility, however, demands changes in farm management such as closer subdivision, heavier and more carefully controlled stocking, and, in some cases, larger areas of supplementary crops and hay to feed the greater number of sheep and cattle during periods of feed shortage. Better provision of drinking water, more access tracks, closer shepherding, but more worries about diseases in stock, such as seasonal hypomagnesaemia in cattle (grass staggers) and pregnancy toxaemia in ewes, are also an inevitable adjunct of higher productivity.

Aerial topdressing has greatly stimulated investment on hill-country farms. It also demands greater managerial skill from the farmer. In all, it has become one of the most important and most beneficial features of our farming industry and one without which we could not progress at the rate needed.

by Cornelius During, B.AGR.SC., formerly Farm Advisory Service, Department of Agriculture, Wellington.

• For further information, see N.Z. Civil Aviation Statistics, 1 Apr 1964.