434 MANAGING ORCHARD SOILS AND FERTILIZING TREES 



tilizers such as nitrate of soda or ammonium sulfate. New 

 nitrogen fertilizers now available may give as good results, 

 for less money, as can be obtained from nitrate of soda. The 

 grower should review the fertilizer situation each year and 

 shop around to determine the best buy. 



The addition of phosphorus has been beneficial only in an 

 indirect way, in that it has seemed to improve the nature and 

 amount of the sod in many sod orchards, and likewise has 

 helped in causing a heavier cover crop to be produced in tilled 

 orchards where it was applied at the seeding of the crop. 



The popular notion of a few years ago that potash would 

 improve the color of fruit has not been borne out in recent 

 experiments. On the contrary, the development of color seems 

 to depend more on having the fruit well exposed to sunlight 

 and other favorable climatic conditions such as the proper 

 amount of moisture and cool nights, and in having it properly 

 matured. The lack of some of these conditions explains, in 

 part, why fruit from orchards fertilized with nitrogen some- 

 times has the reputation of being somewhat poor in color. 

 Such fruit is usually produced under more shaded conditions, 

 unless very thorough detailed pruning is given, since the trees 

 make a more vigorous growth, and thus have more and larger 

 leaves. Its maturity is also delayed, and the fruit on vigorous 

 trees should be allowed to hang on the trees longer in order to 

 improve in color as much as possible and reach a stage of 

 maturity equal to that borne on less vigorous trees. 



3. Deciding How Much Fertilizer to Use and When to Ap- 

 ply It. The amount of fertilizer to use will depend on the color 

 of the foliage and on the amount of new growth being produced. 

 Each orchard thus presents a different problem. One orchard 

 may, under certain conditions, need a heavy application of 

 nitrogen to bring about desirable growth conditions, whereas 

 another orchard under different conditions may need very little 

 or none. 



In orchard sections where it has been found desirable to 

 fertilize most of the orchards each year, the following ap- 



