580 STATE BOARD OF AGRICULTURE. 



nutrition and that strong spurs, well supplied with water and food, 

 are a very important requisite to self-fertility.* It is now considered 

 advisable, therefore, to apply the fertilizer just as early in the spring as 

 growth begins if the eflfect on the setting of the present season's crop 

 and on the formation of fruit spurs for the following season are desired, 

 using such quickly available forms as nitrate of soda or sulphate of am- 

 monia for the nitrogen, acid phosphate for the phosphorus and muriate 

 or sulphate of potash for the potash. Whether any or all of these three 

 essential elements of plant food are deficient in any particular orchard 

 soil is the first question to consider. A soil analysis will not conclu- 

 sively prove this point. A close observation of the present or previous 

 season's growth and production of the trees and a consideration of the 

 general type of top and subsoil, together with the way in which the soil 

 has been handled, should lead to an estimate of the probable deficiencies 

 of the soil. 



Nitrogen. Weak vegetative growth as characterized by a short, thin, 

 new twig and spur development and by the production of small light- 

 colored leaves is generally associated with a lack of nitrogen in the soil. 

 The isandy or gravelly loam soils that characterize our fruit sections are 

 particularly apt to be deficient in this element. Kecent experiments 

 have shown that a lack of nitrogen in the soil especially during the 

 early period of growth, is a most common limiting factor of fruit pro- 

 duction with mature trees.* 



Orchards on strong clay loam soils that are well cultivated and cover- 

 cropped are not so apt to be deficient in this element. When trees are 

 making an excessive vegetative growth as characterized by the produc- 

 tion of long, vigorous, new twigs, large heavy dark green foliage, possi- 

 bly preventing the proper coloring of the fruit or delaying the tree in 

 coming into bearing, it indicates an over-supply of nitrogen. This may 

 be checked by the practice of very light pruning, by light cultivations 

 supplemented with non-leguminous cover crops, by cropping the orch- 

 ard, or by seeding it down for a season or two. Such a condition, 

 while not very general, is apt to prevail on the fertile clay loam soils, 

 particularly about the time the trees have reached a bearing age which 

 may be considered as a transitional stage from that of vegetative growth 

 to fruit production. 



The amount of nitrogenous fertilizer that should be applied to trees 

 is largely a matter of estimate based upon the probable degree of de- 

 ficiency of this element in the soil and the size of the tree. If nitrate 

 of soda is the source of nitrogen used, from 3 to 6 pounds per tree will 

 generally be found desirable. As nitrate of soda tests about 16% 

 nitrogen, this would mean that from one-half to one pound of actual 

 nitrogen was being applied per tree. Upon this basis the proper amount 

 of sulphate of ammonia or other nitrogenous fertilizers to apply could 

 be estimated. 



Phosphorus is an element that is also frequently the limiting factor 

 of groAvth and of fruit production on the orchard soils of this State. 

 Investigations of our Soils Department show tliat the sandy loam soils 

 and sandy soils of our State are commonly low in phosphorus. When 

 phosphorus is deficient in the soil and the moisture and nitrogen supply 



*r)T. Heinicko, Cornell nullptin 393. 

 *Kr:ui8e & Kraybill, ()rcf,'on HuUetiii 149. 



