“According to these data, an acre of land will yield three tons 12 cwts. of nearly dry clover-roots, and in this quantity there will be about 66 lbs. of nitrogen. The whole of the soil from which the roots have been picked out, was passed through a half-inch sieve. The stones left in the sieve weighed 141 lbs.; the soil which passed through weighing 218 lbs.
“The soil was next dried by artificial heat, when the 218 lbs. became reduced to 185.487 lbs.
“In this partially dried state it contained:
| Moisture | 4.21 |
| Organic matter* | 9.78 |
| Mineral matter† | 86.01 |
| 100.00 | |
| * Containing nitrogen | .391 |
| Equal to ammonia | .475 |
| † Including phosphoric acid | .264 |
“I also determined the phosphoric acid in the ash of the clover-roots. Calculated for the roots in a nearly dry state, the phosphoric acid amounts to .287 per cent.
“An acre of soil, according to the data, furnished by the six inches on the spot where the clover was thin, produced the following quantity of nitrogen:
| Ton. | Cwts. | Lbs. | |
| In the fine soil | 1 | 11 | 33 |
| In the clover-roots | 0 | 0 | 66 |
| Total quantity of nitrogen per acre | 1 | 11 | 99 |
“The organic matter in an acre of this soil, which can not be picked out by hand, it will be seen, contains an enormous quantity of nitrogen; and although, probably, the greater part of the roots and other remains from the clover-crop may not be decomposed so thoroughly as to yield nitrogenous food to the succeeding wheat-crop, it can scarcely be doubted that a considerable quantity of nitrogen will become available by the time the wheat is sown, and that one of the chief reasons why clover benefits the succeeding wheat-crop, is to be found in the abundant supply of available nitrogenous food furnished by the decaying clover-roots and leaves.