N'ORFOLK SOCIETY. 473 



There are other advantages of subsoil ploughing. In ferru- 

 ginous soils, a hard pan, occasioned by a deposit of iron, is 

 often found so near the surface as to be injurious to crops. If 

 the soil is sufficiently drained and the hard pan is properly 

 broken up by the subsoil plough, the rain water, in connection 

 with the air, will dissolve out the substances which were inju- 

 rious to vegetation, and give to the roots of plants a wider 

 range for food. 



The advantages of subsoil ploughing on tenacious soils, 

 without underdraining, is at least but temporary. Where 

 there is considerable descent to the furface it has been found, 

 in some instances, to have, for a while, the effect of draining 

 the soil to some extent ; but where there is not much declivity, 

 the water, from being confined, soon packs the earth, even 

 more closely than it was before, so that the ultimate result is 

 rather injurious than otherwise. 



And here it is proper to remark, that the effects of subsoiling, 

 on tenacious soils, even those which have been drained, depend 

 much on the state of the ground, as to moisture, at the time 

 the work is done. Thus, if the subsoil is charged with water, 

 the subsoil plough produces no pulverization, but rather packs 

 the earth more closely, by the pressure it causes in passing 

 through ; but if the subsoil is dry, or comparatively so, the 

 implement thoroughly breaks it in pieces, and it remains in 

 this open condition, allowing the water to pass freely through 

 to the drains below. 



Subsoil ploughing has, in some instances, had a favorable 

 effect in enabling crops to withstand drought, as ascertained 

 by using the implement in alternate breadths through fields. 

 But further and more particular experiments are required to 

 prove its effects with certainty, on different descriptions of soil, 

 and for different crops. 



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