- 7 - 



future are, however, damped considerably by the discounting techni- 

 que itself. That is, the effect on the present value of an error 

 of 50 percent in net income in the 27th year will be relatively 

 small. 



A reasonable manager will also consider the fact that the net 

 return in a given year from an existing orchard can be highly vari- 

 able due to the random effects of weather on yield as well as price. 

 Therefore, the blind application of the $640 criterion might well 

 be wrong. 



In summary: A theoretical decision model does exist for re- 

 placement of orchards. The orchardist may use the procedure as a 

 technique to obtain more information concerning such a decision. 

 This knowledge together with other considerations form the total 

 bank of information the manager uses in exercising his judgment in 

 the decision. 



*************** 



CLEANING THE WEED SPRAYER 



Cleaning the weed spray between sprayings will preserve the 

 equipment, help insure uniform spray coverage, and prevent the 

 chance mixing of incompatible chemicals, or applying traces of the 

 wrong chemical. Below are suggestions for cleaning weed sprayers 

 that appeared in Special Circular 81 entitled "Weed Control Sprayers 

 Calibration and Maintenance" and published by The Penn. State Univ. 

 Extension Service, University Park, Pennsylvania. 



"After each day's use, thoroughly flush with water, both in- 

 side and out to prevent accumulation of chemicals. 



"Choose your cleaning area with great care. It is important 

 to discharge the cleaning water where it will not contaminate water 

 supplies, streams, crops, or injure other plants, and where puddles 

 will not be accessible to children, livestock, pets or wildlife. 



"When you change chemicals, or finish spraying for the season, 

 clean the sprayer thoroughly both inside and out. 



"The following steps are suggested for thorough cleaning: 



1. Hose down the inside of the tank completely, filling it 

 half full of water. Then flush out the cleaning water through the 

 nozzles by operating the sprayer. 



2. Repeat the procedure in step 1. 



