PRIMARY RESULTS 73 



It is not possible to draw any useful conclusions as to 

 the economy of tractor labour from experience on one farm 

 or from one set of figures. The table given above as an 

 example does not suggest that tractor work is cheap in itself. 

 The economic employment of the machine must depend 

 very largely upon ability to keep it in regular use, for whilst 

 labour, fuel, lubricant, and repairs will vary directly with 

 the number of days worked the item of depreciation, which 

 forms the second highest element of cost, accounting as it 

 does for more than one-fifth of the total, will vary more or 

 less exactly in an inverse ratio. It is commonly remarked 

 that, in comparison with horses, a tractor costs nothing 

 when it is not at work, but this hardly states the true facts, 

 and it is obvious that tractor labour cannot stand more than 

 a certain percentage of idle days without an excessive 

 inflation of its cost, though when the advantages of ability 

 to carry out work at speed are taken into account it is 

 equally clear that maximum employment is not the only 

 factor to be considered. The tractor taken for purposes of 

 the illustration given will plough 4 acres per diem, and will 

 harrow or roll 30 acres per diem when running without 

 stoppage. It worked for 193 full days in the year ; the farm 

 extended to 405 acres of which 125 acres were arable land ; 

 one of the questions still to be settled is the minimum limit 

 of area on which the tractor can profitably be employed. 



2. FARM- YARD MANURE 



The determination of the cost of farm-yard manure is 

 one of considerable importance to the farmer. In com- 

 pounding rations for stock the idea prevails so generally 

 that what is wasted as food is recovered as manure, that 

 there is a danger of piling up the cost of dung beyond its 

 value, by too heavy allowances of concentrated food. 

 The high cost of purchased foods and the difficulty of getting 

 supplies during the past few years have done something, 

 doubtless, to counteract this tendency towards extravagant 

 feeding, but the danger still exists and it would be reduced 



