1346 RURAL ECONOMICS 



These rates of depreciation are based on an extensive use of the mach- 

 ines, as is apparent from the low unit rate per acre obtained on taking into 

 account the area annually tilled (see Table II). 



Table II. 



Average value 

 consumed annually 

 Machinery per acre 



For cereals : 



Binders $0,168 



DriUs .072 



Fanning mills .014 



Waggons, sleds and racks .077 



For maize : 



Reapers and binders .604 



Cultivators .223 



Planters .083 



Silage cutters 1.21(1 



Waggons, etc .105 ^ 



For hay : 



Movpers .167 



Rakes .079 



Forks, slings etc .046 



Loaders .095 



Tedders .062 



Waggons, etc .155 



For cultivation generally : 



Ploughs .095 



Harrows .019 



Disc pulverisers .037 



Manure spreaders .337 



1014 - Profit ensured in Southern Rhodesia by Treating Potatoes with Bordeaux 



Mixture. — jack Rupert W., in The Rhodesia A-ricultitral JohdmI, Vol. XIII, Xo. 3 

 pp. 354-360, PI. I-II. .Salisbury, Rhodesia, June 1916. 



The writer proposed to ascertain whether, from the financial point 

 of view, there was any advantage in treating potatoes with Bordeaux mix- 

 ture for control of the disease known as " early blight " caused b}* Alter- 

 naria Solani. 



The experiments, which were continued for three years, dealt with the 

 " Up-to-date " variety, the chief one grown in the region under examina- 

 tion, and also one of the most resistant to the disease. In the experiments, 

 every second row of potatoes was treated and the intermediate row left 

 for control of the results. In this way, the errors due to the differences of 

 fertility in the other plots and those produced by irregularity in the spread 

 of the disease were avoided. Furthermore, the rows treated were never- 

 theless exposed to infection from the untreated neighbouring rows, while 

 in the latter, the risks of infection by the passage of spores from one plant 

 to another were reduced by the presence of treated rows. 



