Arizona Agricultural Experiment Station 591 



WATER REQUIREMENT STUDIES 

 The purpose of this project is to further the development 

 of fruit growing in sections of the State having a comparatively 

 heavy rainfall. It is divided into the following special lines 

 of investigation : 



To determine: (a) the actual water requirement of fruits; 



(b) the effect of pruning on the water requirement of fruits; 



(c) the effect of special cultural practices on the water require- 

 ment of fruits; (d) the environmental factors concerned with 

 plant growth. 



Work on the phase of this project dealing directly with field 

 practice was started in the spring of 1920 at the Prescott Dry- 

 Farm, as outlined in last year's report. However, investiga- 

 tions relative to the actual water requirement of fruits were not 

 begun until February of this year. Because of early bearing 

 and adaptability to a wide range of territory, the peach and 

 grape were chosen for use in the experiment. The plants are 

 confined in waterproof cement tanks constructed and handled 

 so that the amount of water used by each plant can be accu- 

 rately determined. The pruning factor will be embodied in the 

 experiment as soon as the plants have reached the proper stage 

 of development. 



PRUNING STUDIES 



This project, conducted at the Salt River Valley Farm, 

 deals largely with deciduous fruits and involves eight distinct 

 methods of pruning. Two standard varieties of the peach, 

 apricot, plum, and apple are used in the experiment ; and it was 

 enlarged during the past spring to include the Thompson Seed- 

 less and Emperor varieties of grapes. In the case of the grape, 

 six different methods of pruning and training are being fol- 

 lowed. The fruit trees passed their formative stage of growth 

 last season and have been handled since that time according 

 to the several methods of pruning provided for in the outline 

 of the experiment. The work has not reached the point where 

 it can be expected to yield results. 



THE WALNUT AND PECAN 



Progress on this subject has consisted largely in top- 

 grafting commercial varieties of the walnut and pecan upon 

 native walnut stock. The work was started early in the spring, 

 as soon as the bark would slip, and is being continued at inter- 



