104 BOARD OF AGPJCtlLTURE. 



there, but not hitherto drawn upon. There is often, -within a moct- 

 erate distance from the surface, a gre.at amount of mineral matter, 

 ■which only needs full and free exposure to the atmosphere to yield 

 food in abundance ; but while lying undisturbed, is not in a condition 

 to be of any practical value. 



That there are occasional instances in -sYhich deep plowing may 

 for the present be injurious, by bringing up some salt of iron, or 

 other substance, which before protracted exposure, may operate unfa- 

 vorably upon the growth of plaiits is true, and should induce caution 

 with regard to going very deep at once ; but the cases are rare, if 

 tliey even occur at all, in which an additional inch may not be 

 added to the depth of plowing every year, until it reaches a 

 foot in depth, at least, not only Avithout harm, but with positive 

 advantage. This is now so well understood by our best farmers, 

 that the average depth of plowing is probably noaily, or C|uite double 

 what was customary thirty years ago, and it is believed that had the 

 depth of plowing in years past been as great as now, the exhaustion 

 from which Ave suffer would, in many instances, have been much less 

 than it now is. 



The action of the plow is not wholly beneficial, for with all the 

 good which it accomplishes, it tends to render the soil beneath it 

 more compact, and less penetrable to the roots of plants; conse- 

 quently there is the more reason why it should run deep enough to 

 allow the roots of plants plenty of good pasturage. If these have 

 ten inches in depth of well loosened soil in which to ramble and 

 search for food, it is plain that they can thrive better than if confined 

 to five. If the plowing have been year after year at the same 

 depth, say five or six inches, the stratum immediately below it is 

 every time rendered more compact — we often, in such cases, find a 

 crust formed, which is impenetrable alike to the roots of plants and 

 to water, and not only is the soil above exhausted at an early date, 

 but the plants suffer from drought, or from excess of water, as the 

 season proves wet or dry. Besides bringing into action material for 

 the use of plants, deeper plowing, by allowing excess of moisture to 

 pass readily away, is of great use, and not less so in a dry time, for 

 then the soil is in condition to bring up moisture from below, by 

 capillary attraction. To obtain the full benefits of deep plowing, or 

 of subsoil plowing, upon lands overlying an impervious subsoil, 



