The Tillage of Peach Orchards 107 



surface, or if the dust mulch becomes compact, evaporation 

 of the moisture that is in the soil will become excessively 

 rapid and an unnecessary and perhaps serious loss of mois- 

 ture which is needed by the trees will occur. As the surface 

 is made compact by rain, it follows that tillage is advisable, 

 as a rule, after each rainy period or after heavy showers; 

 also as much more frequently as the impaired condition of 

 the dust mulch may make necessary. In irrigated orchards 

 tillage should follow generally soon after each application 

 of water. 



Tillage operations are usually continued, except in special 

 cases, until midseason, the middle of July or the first of 

 August. By that time the growth of the trees for the season 

 will have been largely made, fruit-buds for the next season's 

 crop will have begun to form, the fruit of the midseason 

 varieties will have completed a large proportion of its growth, 

 and the later varieties will finish their development during 

 a period when less moisture is required for the various 

 functions of the tree than earlier in the season. Where 

 cover-crops or green-manure crops are desired, they should 

 be sowed, in many cases at least, by this time. 



However, no arbitrary rules governing tillage operations 

 can be stated, but if a grower grasps the fundamental prin- 

 ciples which underlie the objects of tillage as summarized on 

 pages 101-2, there should be little difficulty in making efficient 

 application of them. It may not be possible — on the other 

 hand, it probably will be impossible — for one to determine 

 with definite accuracy what chemical and bacteriological 

 activities are going on in the soil at any particular time or 

 what in the way of tillage will best promote those activities 

 for the optimum condition of the trees. But as a rule, the 

 changes resulting from them are gradual and their effect 



