MANAGEMENT 51 



extent to delay fruitage. It is needed, therefore, 

 especially on young trees ; but as old trees also 

 must be kept in a state of healthy growth, nitrogen 

 is always required. The nitrogen needs of the tree 

 may be pretty accurately gauged by the color of the 

 foliage. If the leaves are large, glossy and dark 

 green the nitrogen supply is usually sufficient. 

 When they look yellow, small and thin, it is safe 

 to investigate both the nitrogen and the water sup- 

 ply, as the explanation of such symptoms lies usu- 

 ally in a deficiency of one of these. 



Nitrogen is by far the most expensive element in 

 fertilizers, and is, therefore, always to be econo- 

 mized in every way. One of the best ways of 

 economizing nitrogen in orchard management lies 

 in the growing of nitrogen-gathering cover crops. 

 (See page 46.) 



Potash is the fertilizing element next in impor- 

 tance, and is thought to be especially valuable in 

 maturing the crop of fruit. A large percentage of 

 potash enters into the composition of apple seeds, 

 peach seeds, etc. 



The two forms of potash most commonly bought 

 in the market are the muriate and the sulphate. 

 Muriate of potash is largely used and is considered 

 to be one of the cheapest sources of supply. It has 

 the defect of being sour and thus increasing the 

 acidity of the soil. As this condition is especially 

 objectionable to fruit trees, many orchardists have 

 discarded the muriate entirely in favor of the sul- 

 phate. The commercial sulphate is of two kinds, 

 high grade and low grade, the latter containing a 

 certain amount of magnesia, which has somewhat 

 the same effect in the soil as lime that is, a sweet- 

 ening effect. Kainit is a cheap potash fertilizer, 



