EXPERIMENTS ON CLOVER-SOILS. 165 



Nos. 1 and 2 are from a one-year-old crop of clover. The field 

 was a calcareous clay soil. It was somewhat hilly ; or, perhaps, 

 what we here, in Western New York, should call " rolling land." 

 The soil on the brow of the hill, " was very stony at a depth of 

 four inches, so that it could only with difficulty be excavated to 

 six inches, when the bare limestone-rock made its appearance." 



A square yard was selected on this shallow soil, where the clover 

 was good ; and the roots, air-dried, weighed at the rate of 7,705 Ibs. 

 per acre, and contained 100 Ibs. of nitrogen. A few yards distance, 

 on the same soil, where the clover was bad, the acre of roots con- 

 tained only 31 Ibs. of nitrogen per acre. 



So far, so good. We can well understand this result. Chemistry 

 has little to do with it. There was a good stand of clover on the 

 one plot, and a poor one on the other. And the conclusion to be 

 drawn from it is, that it is well worth our while to try to secure a 

 good catch of clover. 



"But, suppose," said the Doctor, "No. 2 had happened to have 

 been pastured by sheep, and No. 1 allowed to go to seed, what 

 magi3 there would have been in the above figures ! " 



Nos. 3 and 4 are from the same field, the second year. No. 4 is 

 from a square yard of thin clover on the brow of the hill, and 

 No. 3, from the richer, deeper land towards the bottom of the hill. 



There is very little difference between them. The roots of thin 

 clover from the brow of the hill, contain five Ibs. more nitrogen 

 per acre, than the roots on the deeper soil. 



If we can depend on the figures, we may conclude that on our 

 poor stony "knolls," the clover has larger and longer roots than 

 on the richer parts of the field. We know that roots will run 

 long distances and great depths in search of food and water. 



Nos. 5 and 6 are from a heavy crop of one-year-old clover. No. 

 5 was mown twice for hay, producing, in the two cuttings, over 

 four tons of hay per acre. No. 6 was in the same field, the only 

 difference being that the clover, instead of being cut the second 

 time for hay, was allowed to stand a few weeks longer to ripen its 

 seed. You will see that the latter has more roots than the former. 



There are 24 Ibs. of nitrogen per acre in the one case, and 51 

 Ibs. in the other. How far this is due to difference in the condition 

 of the land, or to the difficulties in the way of getting out all the 

 roots from the square yard, is a matter of conjecture. 



Truth to tell, I have very little confidence in any of these figures. 

 It will be observed that I have put at the bottom of the table, the 

 result of an examination made in Germany. In this case, the nitro- 

 gen in tho roots of an acre of clover, amounted to 191^ Ibs. per 



