- 173 ~ 



and the inevitable waste. The higher the level of production, the 

 greater will be the waste, and, in consequence, the additions of 

 fertilisers must be doubly increased to maintain the balance. How 

 high a level of production can be profitably maintained is determined 

 by the prices that rule for the crops, but there will always come 

 a limit when the production can be no longer increased by additions 

 of fertilisers except at a loss; at such a stage it is only the in- 

 troduction of improved varieties or some variation of the fertiliser 

 which will still profitably increase the production per acre. 



On examining the variations in farming systems in different 

 parts of the country, it will be found that farmers do instinctively 

 adapt their expenditure on fertilisers (including feeding-stuffs), and, 

 therefore, their level of production to the magnitude of the returns 

 they can get for their produce ; one man will have a large cake bill 

 and spend 40 s. per acre on artificial fertilisers during his rotation: 

 he can maintain a high level of condition, and therefore of waste in 

 his soil, because he can get good prices for potatoes or barley or 

 sheep, whatever his staple product may be. But on poorer land 

 and with less suitable markets a man may be driven to cut down 

 his cake bill and spend only 10 s. per acre on fertilisers, because 

 his products are not valuable enough to compensate for the waste 

 at the higher level of condition in the land. Thus the problem 

 of what is a profitable manure for a given crop becomes a very 

 complex one, and the biggest factor is perhaps the level of pro- 

 duction at which the individual farmer can conduct his business 

 remuneratively > . 



A. D. HALL. The Adaptation of the Plant to the Soil. [Third 

 Masters Lecture]. The Gardeners' Chronicle. N. 3609, p. 143, 

 London, Feb, 26, 1910. 



In delivering the first of the Masters lectures for 1910. Pro- 

 fessor A. D. Hall Director of the Rothamsted Experiment Station, 

 referred to the experiments made at Rothamsted where, ever 

 since 1856, a piece of grass-land had been divided into plots, each 

 plot being continuously manured with a different manure. The 

 leguminous plants make up nearly half the vegetation on the plots 

 receiving phosphates and potash only, while they are absent from 

 plots receiving large quantities of nitrogen in the form of ammo 

 nium salts. Festuca ovina is abundant on plots receiving ammo- 

 nium salts and little seen on plots receiving nitrate of soda. In 



