34 BULLETIN NO. 161 



Let "n"= the number of nights a year that the orchard is 

 heated. 



Let "g"= the number of gallons of oil burned a night on an 

 acre. 



Let "r"= the cost of oil per gallon. 



Let "L"= the cost of labor for heating one acre for one night. 



Let "Dh"= the over head cost and includes the interest and 

 depreciation on the heating equipment, the cost of placing, filling 

 with oil, and gathering up again as well as cost olf clothes of 

 workmen. 



Using the above notation we derive the following equation: 



b (s k) c n (g r+L) Dh IP=iP (1) 



Solving for "s" in this equation we obtained : 



bk+c+n (gr+L) +Dh-fIP-fiP (2) 



s= 



b 



An example will make it clear. Using typical Utah data for 

 an apple orchard and considering the labor (L) as 2 men at 

 $2.50 a night for ten acres or 50 cents per acre and a consump- 

 tion of 100 gallons of oil an acre, the equation becomes: 



400 x.20+50-f-6 (100x.09+.50) +22+.04x300 



s= or s=$0.55 



400 



i. e, considering the yield (b) as 400 bushels of apples a year, 

 the cost of picking and packing a box (k) as 20c, the cost of 

 producing the yield on an acre (c) as $50, the number of nights 

 you must heat the orchard a year (n) as 6, the cost of oil (r) as 

 9c (a gallon) interest on the money invested (I) 4%, then in 

 order to be able to do this you must get at least 50c a box for 

 your apples after they are picked. 



This equation says in words that if you subtract tfrom the 

 amount of money that you receive for the sale of the fruit, the 

 entire cost of producing it, including the cost of heating the 

 orchard and the interest cost on the investment, what you will 

 have left will be profit. If the yield and selling price are high, 

 while the amount of money invested and cost of production are 

 low then you will of course make a large profit, In a section 

 where frost diminishes the yield of 'fruit and by heating the yield 

 is raised to the normal value, then heating must be reckoned as 

 part of the cost of production. If when the interest on the 

 money value of the farm and equipment and the remaining cost 

 of production is subtracted from the amount of money received 

 from the crop during a normal yield, there will be no money 



