540 TRANSACTIONS OP SECTION M. 



method is on a sound basis and is going to increase very considerably the crop- 

 production of the country. 



Now, this is distinctly unfortunate. During the last twenty years the 

 farmers' appreciation of science has been steadify rising, and the most cordial 

 relationships exist between the men of science at the Agricultural Colleges and 

 Research Institutions and the best farmers and agricultural journalists. 

 Promises made in the name of Science are taken seriously and remembered, anrl 

 if they are not fulfilled Science will be blamed. Those of us who are trying 

 to apply Science to Agriculture are placed in the very awkward position of 

 either having to disclaim a piece of work that may finally turn out very useful, 

 or else appearing to acquiesce in a promise — real or implied — that will never 

 be kept. 



The position we have reached is that crop-production may be increased :— 



1 On light soils by more extended cultivation of crops that bring in a higli 

 return per acre, and therefore provide the money for the constant culti- 

 vations and manurings necessary on this class of land. This would 

 involve improvements in the machinery for distribution of the produce. 



2. On heavy land by chalking or liming, followed by drainage. To obtain 



the best results a better system of control of main drains and ditches 

 is needed. Cultivation of this land is always risky, but the risk can 

 be reduced : — ■ 



(fl) By quicker ploughing in autumn so as to bring the work well 



forward : this seems only possible by the use of the motoi - 



plough. 

 {b) By keeping up the supplies of organic matter in the soil; the 



simplest plan seems to be the adoption of the North Country 



system, in which the land is alternately in grass and in tillage. 



There still remains a risk which on present conditions the 



farmer may not feel able to take. 



3. On all soils increased yields may be obtained by increasing the supply 



of fertilisers. 



4. Finally, however, there comes a point where further increases in fertiliser 



dressings cease to be effective : the plant either cannot grow any bigger, 

 or it cannot stand up any longer. 

 o. Further crop increases can only be obtained by finding new varieties that 

 ran grow bigger or stand up better. Considerable improvements may 

 be anticipated by a closer co-ordination of crop variety and soil and 

 climatic conditions. 



But there is another way in which Science can further the problems of croji- 

 production. Instead of aiming solely at increased yields per acre, attempts may 

 be made to reduce the cost per acre and increase the certainty of production. 



One of the most hopeful ways of attacking this problem is to increase the 

 efficiency of the manurial treatment. No manurial scheme is perfect; no farmer 

 ever recovers in his crop the whole of the fertilising constituents applied to the 

 soil; there is always a loss. In our Broadbalk experiments, where wheat is 

 grown year after year on the same land and large dressings of artificials ari- 

 used, we do not recover in the crop more than about 30 to 40 per cent, of the 

 added nitrogen. 



Now, whilst we can never hope for perfect etficiency, i.e. for 100 per cent, 

 recovery, we can hope to do better than this. On our own fields we improve con- 

 siderably on it every year by the adoption of a proper rotation. Thus, whereas wc 

 apply 400 lb. of ammonium salts every year in addition to potash and phosphate 

 on the continuous wheat-plots, and only get 32 bushels of wheat in return, we 

 get the same yield on the rotation-plots without any addition of ammonium 

 salts and even without clover : when clover is introduced we get an even higher 

 yield. There are several causes at work which I need not now discuss. The 

 broad conclusion is that the efficiency of a manurial scheme can be enhanced by 

 arranging a proper rotation, with the practical result that the same yields can 

 be got at less expenditure on manure. 



Further experiments on the relationship between the efficiency of fertiliser 

 action and the rotation are very desirable. Rotation experiments have a way of 



