10 THE HANDBOOK FOR PRACTICAL FARMERS 



This mode of action has been described as a ''slacking" of the 

 soil, althongh technically it is a different ]3rocess. The earth 

 seems to fall apart and loosen to such an extent that certain 

 persons have thought they noticed an elevation of the surface 

 adjacent to the lines of drain. Too much emphasis cannot be 

 placed on the fundamental value of drainage in imjiroving the 

 physical condition of compact soils. 



Fig. 4. — Cutting, pulverizing and compacting tlic vicdhcd .\i one operation. — 

 Bij permission of Dunham Co., Bcicn, Ohio. 



2. Tillage of soil that contains only capillary (film) water is 

 very helpful. If the soil is either too wet or too drj^ the best 

 results cannot be obtained. That nicely moist condition in which 

 a mass of moist soil pressed in the hand will hold its form but 

 will not show free water, is the right stage for proper tillage. 

 ■\^nien too dry, a soil breaks into chunks, or clods, that must be 

 broken down. 



3. Plenty of decaying organic matter in the form of humus 

 is very helpful in developing good tilth. Humus is a dark- 

 colored, gelatinous substance that in many ways helps to pro- 

 duce granular structure. The tendency of soils to settle and 

 bake after years of cultivation is often due to exhaustion of the 



