360 



disintegration, under the most favourable circumstances, for 

 three weeks. No doubt, at the time the clover died away, 

 not the slightest portion of soluble potash could have been 

 detected, for, be it remembered, that during the heavy rains 

 of winter and spring, considerable quantities of soluble matters, 

 potash, &c., are washed down beyond the reach of the roots of 

 plants, and this, together with the portion extracted by the 

 plant itself, leaves nothing to supply its future demands ; nor 

 is the quantity separated by disintegration in this soil sufficient 

 to do so ; for, considering the state of the ground during the 

 growth of clover, I should certainly say that not more than 

 2 lbs. of potash would be liberated per week ; consequently, 

 only 20 lbs. would be liberated during ten weeks the clover 

 plant was growing ; hence there would be a deficiency of at 

 least 6 lbs. for the crop. 



With these facts and considerations before me, I think I 

 am justified in concluding that the failure of the red clover 

 crop (particularly its disappearance during winter and spring) 

 is mainly owing to a want of soluble potash in the soil. I 

 am particularly borne out in these conclusions, by the fact of 

 all causes which tend to liberate potash from its combination 

 with silica, having the efi^ect of preventing its death; and 

 also by the entire success of the red clover plant in soils 

 where potash abounds. You all observe the success of a 

 wheat crop after a good crop of clover, now this proves that 

 much silica and potash has been liberated during its growth, 

 because the remaining portion of the former which the clover 

 does not require at all, contributes mainly to the success of 

 the wheat. The effect of lime, too, in preventing the failure 

 of clover, has often been observed, and this is undoubtedly 

 owing to the well-known effect of lime rendering soluble the 

 potash of soils. 



With regard to such crops as turnips, which require more 

 potash than clover, it must be borne in mind that the soil is in 



