given treatment. These samples were obtained by harvesting 

 14 X 14 ineli areas. The seven-ineli sparing of tbe band seeder 

 furrow openers dictated the qiuuhaiit dimensions used. The 

 herbage was oven-dried. The yield results are expressed as 

 the average weight of dry herbage per sample unit. Plant 

 counts were made after the yi<dds were taken. Tbe sample 

 area was the same as that used for yield data. Representative 

 phints were dug and taken to the laboratory for crown and root 

 damage studies. 



For evaluating plant damage, three criteria were used: (1) 

 Plant counts (2 I crop yields (3) crown damage. 



Experimental Results 



Results of the plant count studies showed this method to be 

 unsatisfactory for evaluating plant damage. Regrowth from 

 damaged plants was included in the plant counts: therefore 

 plant counts were not indicative of the reduction in yield. 

 However, they did indicate good stand estal)lishment. 



Results of the 1959 plant harvest y ields are shown in Figures 

 3 and 4. Statistical analysis of tlie alfalfa yields showed that 

 both new and smooth tires inflicted significant damage, when 

 compared with the control plot. Increasing the drawbar load and 



ALFALFA 



CONTROL 500 1100 1500 CONTROL 



DRAWBAR PULL IN POUNDS 



Figure 5. Effect of increasing drawbar pull with 

 new tires on vields of alfalfa (1960). 



650 1250 1800 



smooth tires and 



