112 WHEAT PRODUCTION IN NEW ZEALAND 



general trend of the average are exactly the opposite 

 to these movements in yield per acre. This confirms the 

 law of diminishing returns, which states that after a 

 certain stage has been reached fresh additions of capital 

 and labour to land do not yield corresponding returns. A 

 modification of the law states that as the margin of 

 cultivation extends and more land is brought under 

 cultivation, the return per unit decreases. But the law 

 of diminishing returns does not fully account for these 

 movements in yield per acre. For, in the first place, the 

 persistent decline of the yield during the " eighties" 

 cannot be the result of soil exhaustion, nor of the intro- 

 duction of inferior soils, since, as far as can be gathered, 

 wheat production did not extend to these on a large 

 scale. Secondly, the remarkable rise of 10 bushels per 

 acre in the yield in the decade after 1895 at once suggests 

 that more scientific methods of culture were introduced. 

 These graphs showing comparisons in yield per acre and 

 acreage for Canterbury and Otago individually, and for 

 New Zealand as a whole, are full of suggestion and 

 conclusively support the view that mixed farming is 

 the most successful type for the wheat producing area 

 of New Zealand. 



I have said that the change in agriculture since 

 the "eighties" has been in both structure and technique. 

 Structural changes have been brought about by the 

 conversion of the large agricultural estate into a com- 

 paratively small farm where both agriculture and 

 pastoral pursuits are followed. The introduction of 

 intensive cultivation in contrast to the unscientific 

 methods of cropping practised on the large estate has 

 fundamentally altered the technique of agriculture. It 

 has been demonstrated that during the period of large 

 scale production wheat growing was pursued extensively 

 with little respect to the methods of cultivation and the 

 distribution of energy over the field of production. This 



