May, 1921. 



SCIENTIFIC AGRICULTURE 



Plows and Plowing 



By J. MacGREGOR SMITH, 

 Professor of Agricultural Encriiieerino:, Univei-sity of 

 Alberta, Edmonton. 

 (Conchided from the April issue.) 



PARTi II. 



203 



Hitch Not Right. 



Now we have come to t^ie last source of trouble 

 and probably the cause of more plow trouble than 

 all the rest put together. Therefore we will be just- 

 ified ill going into some of t.he factors underlying, 

 the draft of plows. They must be thoroughly under- 

 stood if we are to hitch intelligently to a plow. From 

 the questions asked and t^e interest shown it may be 

 safely said that farmers are at least interested and 

 anxious to hear the subject discussed. After this 

 point the battle is won. When you hear of a new 

 idea you do not pass your opinion nyyon it right away, 

 but if you find that it may be of value you most 

 likely adopt the new plan. 



When hitching four horses to a wagon, would you 

 consider it good practice to put three on one side 

 of the tongue and one on the other? You hitc/i to 

 the centre of your stoneboat. Why? For the simple 

 reason that it pulls straight. AMiy do you u'>t jiiitch 

 to the centre of your plow? If you plow tandem or 

 four abreast, with one hoi-se on the plowing, one in 

 the furrow and two on. the unplowed ground, you do 

 hitch to the centre; but if you put one in the furrow 

 and three on tjie land, you do not. If you have a 

 good farm and can get on a good half mile furro\>' let 

 me show you why you should plow tantlein. 





Figure OA 



Take a Itoard and bore a hole in the centre, and 

 when you attach a string and pull it ah)ng you will 

 notice it pulls straight. Bore another hole in one 

 corner and you will see that the board pulls at an 

 angle. T,he centre line is the load line or centre of 

 draft line and is fixed for the board and the stone- 

 boat. But. you say. what has this to do with the 

 plow? Where is the centre line in the plow? 



It Is about two inciies inside the landside of the 

 plow bottom (see Figures 10, lOA and lOB). It may 



move closer to the centre in the steeper form;' of 

 mold boards. You will see the loadline for Ciich plow 

 Ixittom marked as well as the centre of draft line 

 for tlie plow, 19 inches from the furrow wall. Why 

 is the load line not in the centre of each furrow? 

 Because it takes 50 per cent of the total draft of t*ie 

 imjilement to cut the furrow slice, aJid therefore the 

 loadline is nearer the landside. You cainiot hitch 

 four abreast (and further reference to four abreast 



Figure 10. 



means three on the land and one in the furrow) 

 and hitch at a point 19 inc^ies from the furrow wall. 

 You have to hitch further to the land and the result 

 is the plow pulls at an angle. (See Figure IOC.) 

 To overcome this twisting effect you give y(mr front 

 furi-ow wheel "lead'' away from the land. Is that 

 not so? It takes power to hold tiie plow straight. 



Fiiiure lOA. 



