Effects of Subsoiling 141 



dance of it in the unstirred soil below, but now prevented from 

 rising into the root zone by the reduced rate at which it is possible 

 for the water to rise. 



This is a matter of great importance to comprehend, because 

 in a humid climate, where the subsoils frequently become satu- 

 rated with water, rendering them unfit for the feeding ground of 

 roots, to develop a deep mulch over this by subsoiling would tend 

 to maintain this lower soil permanently in a condition which 

 excludes the roots of plants from it, while at the same time that 

 water cannot rise into the loosened soil above, and a drought 

 actually occurs when, if the field had not been subsoiled, a good 

 supply of water might easily be reached by the crop. 



In the arid and sub-humid regions, the saturated subsoil is 

 rarely found, except for short periods, at long intervals apart, 

 and hence there is little danger from this score in subsoiling in 

 these climates. 



How subsoiling allows the water to enter the soil more readily. 

 From what has already been said, it will be understood that it is 

 only after the subsoiled layer has become saturated that water 

 begins to percolate through it, and so to store itself in the 

 undisturbed layer below. But when rain enough has fallen to 

 accomplish this result, then whatever else falls drops readily and 

 rapidly through it, not only because there are wider channels for 

 the water to move through under the stress of gravity, but because 

 from an open soil the air escapes quickly and readily, thus making 

 place for the water which cannot enter until the space for it has 

 been vacated. The water entering the soil in time of rain or irri- 

 gation is like water entering an open-mouthed jug, which can only 

 do so as rapidly as the air is permitted to escape. 



A larger percentage of the water contained by subsoiled ground 

 available to crops. With all soils, of whatever kind, there is a cer- 

 tain amount of water they contain which it is impossible for the 

 roots of plants to remove with sufficient rapidity to meet their 

 needs, and this amount is relatively smaller in the coarse-grained 

 soils than it is in those having a finer texture. But whenever any 

 soil has been subsoiled, and its water-holding power thereby 

 increased, this extra amount of water becomes wholly available to 



