42 



produces considerably more food than grassland ; one acre of arable 

 land yields on an average more than half a ton of flour and over live 

 tons of potatoes; but it commonly gives less than one hundredweight of 

 beef, and sometimes considerably less. Translated into food units, 

 one acre of arable land furnishes sufficient calories to keep a man going 

 for 500 to 1,500 days, according as cereals or potatoes are grown : 

 while an acre of grass will only furnish sufficient calories to keep liim 

 going for 6 to 200 days, according as it is used for rough grazing or as 

 good pasture for dairy stock. 



On the other hand the cost of working the aral)le land is considerably 

 higher. Numerous estimates are available of the cost of growing 

 wheat. These show^ that prior to the War it. was about £6 to £S j^cr 

 acre ; during the War it has risen to £10 to £12 per acre. Less informa- 

 tion is available as to the cost of growing other crops, but at 

 Rothamsted barley and oats cost sometimes more and sometimes less, 

 but on an average almost as much as wheat ; mangolds cost £14 per 

 acre before the War, but £18 now ; while potatoes cost £20 before the 

 War and £24 now. Moreover, the farmer has to stand out of his money 

 for many months. Grassland, on the other hand, costs much less per 

 acre, and the money is turned over more quickly. Less capital is 

 therefore required for grass than for arable land. 



But if the cost of working arable land is greater than that for 

 grassland the returns are also higher. Recent instances are quoted in 

 which grassland that only yielded 10 to 15 cwts. of hay per acre, or 

 kept only one sheep or less per acre, gave, when ploughed up, from 

 40 to 70 bushels of oats, and similarly good yields of other crops. 

 Further, arable farming presents far greater possibilities of improve- 

 ment than grass farming. Ordinary grassland can rarely be made to 

 yield more than 40 cwts. of hay or 2 cwts. of beef per acre, but the 

 possibiHties of arable land are considerably greater, and the gross 

 returns may be pushed up very considerably. There is, of course, a 

 corresponding increase in risk, but this can be diminished by the 

 adoption of co-operative methods and by the technical improvements 

 that one hopes will be forthcoming. 



XXXV. " How can Crops be Grown without Potash Manures next 

 Year ? " E. J. Russell. Journal of the Board of 

 Agriculture, 1915. 22, 393-4o6. 



Two methods can l)e adopted (i) other sources of potash can be used 

 instead of the usual Stassfurt salts, (2) the reserves of potash in the 

 soil can be made available. It is shown that various plant ashes, bon- 

 fire ashes, etc., contain about 10 per cent, of potash (K.^O), not much 

 less than is present in kainit. Sheltering the manure heap w^as found 

 to reduce loss of potash considerably, an exposed heap losing 30 per 

 cent, of its total potash, while a corresponding sheltered heap lost 

 12 per cent. only. The ploughing up of grassland and clover leys also 

 sets free potash stored up in the root residues. The utilisation of 

 potash stored in the soil is made possible l)y liming the land or applying 

 dressings of sodium salts, such as agricultural salt or sulphate of soda. 

 Salt lias long been known to l)enefit mangolds, and on light land it has 

 good effects on most other crops. Sodium salts have the further 

 advantage of economising the supplies of potassium salts. The appli- 

 i'ation of tliese Narioiis methods to different crops is discussed. 



