FERTILIZING 109 



from 25 to 50 pounds of actual potash (K,0) should be applied 

 on each acre of bearing trees. Where potash is not known to be 

 lacking in the soil, the smaller amount may be used, and after a 

 little testing it may even be found wise to omit it altogether. With 

 the smaller amount of potash the essentials of the present com- 

 bination are carried in 500 pounds of a 6-10-5 fertilizer or its 

 equivalent. In the ordinary ready-mixed fertilizers the nitrogen is 

 likely to be carried in ammonium sulphate, with which some liming 

 may be necessary if many applications are made, and especially if 

 leguminous cover crops or permanent covers are to be grown. In 

 either special or homemade mixtures the various elements may be 

 carried in any of the materials indicated in the table. 



Time and method of application. 1 The time of application of the 

 fertilizer we believe to be of distinct importance, especially in the 

 case of nitrates. While our evidence on this point is by no means 

 complete, we have found indications that nitrates can be applied 

 too early in the season and thus be wholly lost to the trees. There 

 is also evidence to support the theory that distinct harm may result 

 from their application about fruit-setting time — especially in the 

 case of the peach tree. We feel, therefore, that the nitrates should 

 be applied not earlier than petal-fall in apples and probably not later 

 than the middle of July. In general, about the middle of this period 

 should be all right, though some of our most striking results have 

 come from applications made as late as July 8. 



In the case of the mineral ingredients, with their lower solubility 

 and slower action, the time of application is less important. Some 

 careful orchardists engaged in commercial work apply phosphates 

 and potash to their peach orchards in the fall, and believe that this 

 gives best results. Thus far, however, we have felt that the time 

 of application for the minerals is of relatively little importance, since 

 they are quickly fixed in the soil in any case, and do not leach 

 readily. We therefore apply them with the nitrogen at the time 

 considered best for the latter. Manure also can be applied at almost 

 any time, except possibly late summer or the fall, without danger 

 of loss or other ill effects. Attention should be given to chapter 

 on manure. 



1 From the report of experiments conducted by J. P. Stewart, horticulturist, 

 Pennsylvania State College. 



