HOW TO MAINTAIN FERTILITY 



and two per cent of potash. About sixty bushels 

 per acre of the green seed or its equivalent of 

 meal, together with about one thousand pounds of 

 a complete fertiliser, will be a good dressing for 

 the garden. 



Nitrogen in the form of ammonia is derived 

 almost exclusively from sulphate of ammonia, the 

 commercial product containing about twenty per 

 cent. This form of nitrogen is easily converted in 

 the soil to nitrate, the form in which it is used by 

 plants, but before being converted it will readily 

 combine with the soil becoming fixed, so that there 

 is no danger of its leaching. This quality makes 

 it very valuable for light, sandy loams and for 

 use in wet seasons, when nitrate of soda would 

 leach from the soil rapidly. 



The commonest form of commercial nitrogen is 

 nitrate of soda, which contains about 15.5 per 

 cent of nitrogen. Nitrate of soda dissolves at 

 once upon being put in the soil; it has a strong 

 affinity for water. In this form the nitrogen is at 

 once available to the plants. As it is so soluble, 

 there is danger of its being leached from the soils, 

 especially sandy soils, if more is given than the 



plants can use in a short time. 



[37] 



