88 CULTIVATION OF THE SOIL. 



class, including rye and oats, buckwheat, corn, and other ce- 

 reals, may not add plant-food to the soil, but the rotting of the 

 tissues affords vegetable mould or humus, and therefore may 

 greatly improve the land. By holding the snow and prevent- 

 ing the washing by rains, and by preventing the cementing of 

 hard soils, they may also exert a distinctly beneficial mechan- 

 ical influence. It is an easy matter to use too freely of legu- 

 minous crops, since one is likely to secure too much nitrogen, 

 and induce too large a growth. This is particularly true with 

 grapes, peaches, and various tender fruits. For hard and 

 rough soils, the best general cover in the North is rye, and in 

 the South cow-peas. In the North, the crimson clover may 

 be used now and then, but it is successful, as a rule, only 

 on lands which are fairly rich and fine, in which the plant is 

 able to secure a good foothold comparatively early in the 

 fall. Whether one shall use a cover-crop every year de- 

 pends upon the condition of his land and his trees. The 

 orchardist will have to determine that point for himself. 



Fertilizers. 



The old notion that the chemist can analyze the soil and 

 then tell what kind of fertilizer, and how much, shall be ap- 

 plied to it, is now given up. The chemist can tell what is in 

 the soil, but in the Northern States, where the soil is largely 

 composed of drift, the land is usually not suflSciently uniform 

 to enable the chemist to get a representative sample of the 

 whole field. Judicious and thorough tillage will unlock much 

 of the plant-food which the chemist finds to be unavailable. 

 The chemist can give hints and suggestions here and there, 

 but only in exceptional cases can he give positive and specific 

 directions. 



. As a rule, there are only three of the elements of plant-food 

 which the fruit-grower needs to add to the soil — potash, phos- 

 phoric acid, and nitrogen. Good tillage may supply these, or 

 at least make them available. If trees are not making a good 

 growth and are of a yellow cast, one or all of three things is 

 to be suspected: they may be attacked by borers or other 

 difficulties; they may be suffering from lack of moisture; 

 they may lack nitrogen. If the grower is satisfied that they 



