HOW MUCH FERTILIZER TO USE 



435 



proximate amounts of nitrate of soda, or its equivalent in other 

 nitrogen carriers, are being used: l^ pound on 1- and 2-year- 

 old trees, and 14 to 1 pound on 3-year-old trees. These 

 amounts are then gradually increased until 2 to 4 pounds are 

 used for 6- to 10-year-old trees, and 5 to 10 pounds for trees 

 ranging from 15 to 30 years old. These amounts should serve 

 only as a general guide, however, as the growth and fruiting 

 of the tree should be used as an index of how much fertilizer 

 to add. 



In general, it is not a good practice to place fertilizer in the 

 hole at planting time; in fact, severe injury to the tree may 

 result. Good results are often obtained by applying the fer- 

 tilizer on top of the soil in a circle 6 to 8 inches from the trunks 

 after growth of the trees has started. 



Since quickly available nitrogen fertilizers are applied to 

 increase fruit spur and terminal growth and the ^^set^^ of blos- 

 soms, as well as to increase the color and size of foliage and 

 fruit-bud formation, and to influence other factors, it should 

 be remembered that fruit-spur growth in length is generally 

 completed within two weeks after blossoming, and that ter- 

 minal growth is usually over in most sections and seasons by 

 July 15. These facts being known, it is at once apparent how 

 important it is to apply fertilizers early in the spring (about 

 one month before blossoming). 



In orchards on light, sandy soils where considerable leach- 

 ing may occur, it may pay to split the applications: about 

 two-thirds of the amount decided upon should be applied before 

 the terminal buds start to grow, and the other third just after 

 blossoming when the set has been determined. 



Results in some fruit regions indicate that it might be de- 

 sirable to apply part of the nitrogen in the spring and part in 

 the fall each year, but further studies are needed before grow- 

 ers in all regions should adopt such a practice, except in an 

 experimental way. 



Thus far it has not been possible to eliminate biennial bear- 

 ing through the use of fertilizers. 



