ROLLING, PLANKING, AND HOEING 175 



cineraria or petunia seeds into the soil with a board 

 all are illustrating, on a small scale, the_,phil- 

 osqphy of rolling. 



OTHER BENEFITS OF ROLLING 



The chief purpose of rolling, in ordinary farm 

 practice, is to increase the supply of moisture for 

 the seeds, but it may serve other useful purposes, 

 or it may be used for these alone and not for mois- 

 ture. Rolling to crush lumps is a profitable and 

 common practice on soiTs~~which become cloddy. 

 Great care must be taken, however, not to roll these 

 soils when they are wet, as they are then cemented 

 into a hard crust by heavy rolling. There is a time 

 between wetness and dryness when the clods 

 crush easily; this is the time for rolling. The 

 seeds are brought into close contact with the soil 

 by rolling, while they might lie dry and unre- 

 sponsive among the clods. Rolling heavy soils in 

 spring after seeding is beneficial if the season is 

 dry, but injurious if the season is wet. 



The benefits from crushing clods lie not only in 

 the improvement of the soil conditions as affecting 

 germination, but also in the liberation of the plant 

 food that has been locked up in the lumps. Rol- 

 ling heavy soils, when the chief object is to crush 

 clods, is always attended with more or less un- 

 certainty as regards its influence on the moisture 

 of the soil; so it is usually preferable in such cases 

 to break the lumps with a planker or clod-crusher 

 instead of running the risKs of rolling. An in- 

 cidental benefit of rolling, on some soils, is that it 

 presses all small stones on the surface into the 

 ground, so that they will not interfere with 

 harvesting. 



