2$ SOIL IMPROVEMENT. 



For 203 pounds of nitrogen, as an average, are 

 required 202 pounds of potash and 49 pounds of phos- 

 phoric acid. That means for every pound of nitrogen 

 u made " by the use of legumes, the crop must have used 

 one pound of potash and about one-quarter of a pound oj 

 phosphoric acid. 



Mucli has been said about clovers " leaving the soil 

 better than they find it," and it is the common belief 

 that they improve the soil. This is true in one sense, but 

 not in another. To illustrate, a clover crop, cut for hay, 

 removed from the soil per acre about 184 pounds of 

 potash, 15 2 pounds of phosphoric acid and 212 pounds of 

 nitrogen. Of this most of the nitrogen may come from 

 the air, but the potish and phosphoric acid come from the 

 soil, and when the crop is removed, the soil is poorer by 

 just that much potash and phosphoric acid. The rowen, or 

 after-crop, contains nitrogen which may be turned into the 

 soil ; also, the roots and stubble count for something. At 

 che same time, all must keep in mind, that the gain is in 

 nitrogen only, and there is not even this gain if potash and 

 phosphoric acid are lacking. Clover failure is very 

 common, indeed, but a farmer rarely stops to think that 

 exhaustion of the soil in potash and phosphoric acid may 

 be the cause of it. 



To sum up : To use legumes profitably, they must be 

 well supplied with potash and phosphoric acid, and the 

 crop either turned under as green-manure, or used as 

 forage and returned to the soil as farmyard manure. In 



