CHAPTER VIII 



ROLLING, PLANKING, HOEING 



FARMERS have long noticed that grain 

 sprouts quickest wherever the horses' hoofs 

 have trod. Gardeners have observed the 

 benefits of walking above newly planted vegetable 

 seeds. They have noticed, also, that the soil on 

 the bottom of the hoof track or foot print is more 

 moist than adjacent soil. The conclusion has 

 been that compacting the surface soil makes it 

 more moist; this view is held by many farmers. 

 Rolling, which had its origin in these observations, 

 is practised by many with the idea that it increases 

 the amount of moisture in the soil. 



ROLLING TO ASSIST GERMINATION 



The chief object of rolling on many soils is to 

 increase the amount of water supplied to the ger- 

 minating seeds, but rolling does not actually in- 

 crease the total amount of water in the soil; it 

 diminishes it. Rolling compacts the surface soil, 

 bringing the particles closer together so that film 

 water passes upward more readily and is lost by 

 evaporation. But while passing upward much of 

 it comes into contact with the seeds and is absorbed 

 by them; thus the seeds are supplied with more 

 moisture and germinate quicker and better, even 

 though it is at the expense of a loss of water to the 

 soil. Since so much of the success of a crop 



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