Phosphatic Fertilisers. [June, 



as potatoes are liable to scab if alkaline conditions are set up by 

 the basic slag. Further,, it is not certain that heavy dressings 

 of phosphates are always desirable for potatoes; in Devon 

 experiments 400 lb. superphosphate per acre gave a somewhat 

 larger yield than did 533 lb. per acre. 



For swedes and turnips superphosphate serves the admirable 

 purpose of bringing them earlier to the hoe than would other- 

 wise be possible. This alone often justifies the use of the 

 fertiliser quite apart from the increase in crop and of feeding 

 value. For these crops, however, basic slag is often equally 

 effective in the north, though not always in the south ; but it is 

 always to be preferred wherever finger-and-toe is common. 



Mangolds commonly receive a dressing of superphosphate to 

 bring them on earlier, but as a rule there is no point in applying 

 large dressings; probably 2j- cwt. per acre is all that is needed. 

 Indeed there is some evidence that too much superphosphate 

 has the undesirable effect of reducing the growth of the bulb 

 and hastening the ripening of the crop, i.e., the formation of 

 seed. 



For Cereals. — Another highly important use of superphos- 

 phate is in hastening the ripening of cereals, this being of espe- 

 cial advantage in districts where the harvest is apt to be late. 

 Thus in wet hill districts the harvest is sometimes a source of 

 serious anxiety to farmers and there is a great advantage in 

 expediting it. if only by 6 or 7 days. This has been done by 

 giving a dressing of about 3 cwt. superphosphate along with a 

 small amount (say § cwt.) sulphate of ammonia, to ensure an 

 early development of leaf. 



Superphosphate is also used with advantage on barley grown 

 after roots which have been fed to sheep on the land, especially 

 when cake or corn have also been given. It counteracts the 

 rankness that tends to be induced, improving the quality of the 

 grain and increasing the strength of the straw. The same kind 

 of action takes place when superphosphate is added to the nitro- 

 genous top-dressing given to cereals in the ordinary corn-growing 

 districts. Increased yields are obtained by applying nitrogenous 

 dressings to corn crops in spring. There is, however, often the 

 fear that the corn will be laid owing to the inability of the 

 straw to carry more grain. Experience has shown that this 

 tendency is frequently reduced by the addition of 1 to 1J cwt. 

 of superphosphate to the dressing. 



Effect of Soil and Rainfall. — As a rule dry sandy soils in the 

 eastern and midland parts of the country, where the rainfall is 



