220 CHEMICAL FERTILIZERS 



of sulphate of ammonia will be sufficient. In Lancashire, 

 where no farmyard manure is used, as much as 6 cwt. of 

 superphosphate, 2 cwt. of muriate of potash and 2j cwt. of 

 sulphate of ammonia aie used, although in most districts 

 muriate of potash is thought inferior to the sulphate for 

 potatoes. In Devonshire it has been observed that large 

 amounts of phosphates and nitrogen are of little value, but 

 that the ordinary dressings of potash may be increased with- 

 out harm. Where liberal dressings of farmyard manure are 

 obtainable in the northern counties, 10 tons of dung, i cwt. 

 sulphate of ammonia, 2 cwt. basic slag and ij cwt. super- 

 phosphate are recommended. On peaty soils the sulphate 

 of ammonia can be reduced, if not actually dispensed with, 

 but phosphates and potash are generally necessary. On the 

 whole, sulphate of ammonia and superphosphate have 

 proved the most satisfactory fertilizers for potatoes. Nitrate 

 of soda has rarely given good results, but basic slag has 

 proved very advantageous in some districts. 



Leguminous Crops. Under modern conditions of British 

 agriculture, beans only play a small part ; generally they 

 come between two straw crops. A little farmyard manure, 

 phosphate and potash may be used, but nitrogenous manures 

 should be left out for this crop in the rotation. Beans are 

 grown very largely for their subsequent beneficial effect upon 

 other crops, and cannot be considered by themselves. About 

 4 cwt. of basic slag applied to the bean crop may be very 

 successful, but further expenditure of fertilizers is not likely 

 to be repaid. 



Clover. Red clover is a means of supplying the soil 

 with nitrogen derived from the air. As clover cannot be 

 grown continuously on the same land, manurial treatment 

 cannot be considered separately from the rest of the rotation- 

 Even on the best clover soils in the country, clover can rarely 

 be grown more frequently than once in seven or eight years, 

 lyime and potash salts are certainly helpful, and phosphates 

 are good. Clover is nearly always sown in the barley cro p 

 and therefore the manure is applied to the barley. It is 

 better, therefore, that the barley crops, and perhaps even 



