578 



STATE BOARD OF AGRICULTURE. 



periods wlieu the fruit spur is developing and storing its food supply 

 for the following season; also, during the setting and developing of the 

 fruit. Maintaining a high organic content of the soil, to enable it to 

 hold more soil moisture, by manuring or cover-cropping, heavy mulch- 

 ing with straAV, and the early plowing of cover crops followed by regu- 

 lar cultivations, are practices which tend to insure an ample and uni- 

 form moisture supply. 

 While the temperature and moisture conditions of the soil are factors 



FIG. II. A STEONG FKUIT SPUR CHARACTERISTIC OP PRODUCTIVE TREES. 



that greatly influence growth, the availability of the chemical elements 

 in the soil is a most common limiting factor. This deficiency of avail- 

 able chemical elements in the soil may be due to the fact that the soils 

 are ''infertile'' or are deficient in one or more of these elements. Other 

 orchard soils are rich enough but the elements are not in available 

 forms at the most favorable season for growth. Studies of the Soils 

 Department on the relative availability of nitrogen, phosphorus, potash 

 and such other essential elements in the soil at different periods of the 

 growing season show that in very early spring there is a very slight 

 amount of these elements present in available forms. As the season 



