64 CAMPBELL'S SOIL CULTURE MANUAL 



packing, as shown in cut No. 4, we have that firm strat- 

 um at the point where the roots mainly grow, and with 

 our loose mulch on the surface we prevent the loss of 

 our moisture by evaporation. 



Cut No. 5. Sub-surface Packer. 



Results obtained by Professor King in these one hun- 

 dred and forty-seven tests certainly prove very effectually 

 the correctness of the conclusion of sub-packing. We 

 secure a much deeper or thicker stratum of packed soil 

 than can possibly be secured from a surface roller. This 

 would of itself create a greater force of capillary lifting 

 power. Then again, and don't lose sight of this fact, 

 as the sub-packed soil lifts the moisture it is not lost by 

 evaporation as is the moisture from the surface packed, 

 but is held there beneath the loose surface or soil mulch. 

 This fact causes an accumulation of moisture in the packed 

 portion which further aids in the upward movement of 

 the moisture from below. This translocation of water 

 brought about by the sub-packing is of the highest im- 

 portance when we reach the long dry periods so common 

 in midsummer, a condition we rarely fail to get some- 

 time each and every year. We have proven by practical 

 tests, over and over again, that by this increased move- 



