iv] WHEAT 45 



(b) Special circumstances. Wheat at 50s. Straw at 20s. 



Single Double Treble 



dressing dressing dressing 



s. d. s. d. s. d. 



Value of increase 338 6 10 10 871 



Cost of extra manure 160 2 12 3 18 



Profit on extra manure ... 1 17 8 3 18 10 491 



The additional cost of harvesting the larger crops is not 

 included, and has still to be deducted from the profits. 



On the other Broadbalk plots it is shown that a double dressing 

 of nitrate of soda gives better results than a single dressing. The 

 figures are : 



Single dressing ... 13-5 bushels increase, 

 Double dressing ... 4-2 bushels additional increase. 

 The dressings contain the same amount of nitrogen as 200 and 

 400 Ibs respectively of sulphate of ammonia : thus on the basis 

 of equal nitrogen content the nitrate of soda gives the better 

 return. Roughly speaking each additional hundredweight of 

 nitrate of soda or sulphate of ammonia up to 4 cwts gives an 

 additional sack of wheat per acre. At present prices this is 

 profitable (see Fig. 8, p. 24). 



The following dressings may be suggested: 



Lighter soils. 



Autumn or Spring. 2 cwts superphosphate unless the pre- 

 ceding crop received 3 or 4 cwts. 



Spring. 1 to 2 cwts nitrate of soda or sulphate of ammonia. 

 2 cwts of salt, where kainit is known to be beneficial. 



In districts of low rainfall, however, these dressings may not 

 prove remunerative. Farmyard manure will probably be the 

 best under these circumstances. 



Heavier soils. 



Autumn. 2 or 4 cwts superphosphate or basic slag, especially 

 if the winter is usually wet and the plant stands still, or if the 

 weather at harvest time is uncertain. Superphosphate could, 

 however, go on as a spring dressing. 



As a rule the wetter the climate and the heavier the soil, the 

 more pronounced becomes the need for phosphates. 



