“The roots from the field after clover-seed, it will be borne in mind, were dug up in November, whilst those obtained from the land twice mown, were dug up in September; the former, therefore, may be expected to be in a more advanced state of decay than the latter, and richer in nitrogen. “In an acre of soil, after clover-seed, we have: Lbs. Nitrogen in first six inches of soil 4,725 Nitrogen in roots 51½ Nitrogen in second six inches of soil 3,350 ------- Total amount of nitrogen, per acre, in twelve inches of soil 8,126½ ======= “Equal to ammonia, 9,867 lbs.: or, in round numbers, 3 tons and 12½ cwts. of nitrogen per acre; equal to 4 tons 8 cwts. of ammonia. “This is a very much larger amount of nitrogen than occurred in the other soil, and shows plainly that the total amount of nitrogen accumulates especially in the surface-soil, when clover is grown for seed; thus explaining intelligibly, as it appears to me, why wheat, as stated by many practical men, succeeds better on land where clover is grown for seed, than where it is mown for hay. “All the three layers of the soil, after clover-seed, are richer in nitrogen than the same sections of the soil where the clover was twice mown, as will be seen by the following comparative statement of results: --------------+--------------------------+-------------------------- | I. | II. | Clover-Soil twice | Clover-Soil once mown | mown. | and then left for seed. +--------+--------+--------+--------+--------+-------- | | | | | | | Upper | Second | Third | Upper | Next | Lowest |6 inches|6 inches|6 inches|6 inches|6 inches|6 inches --------------+--------+--------+--------+--------+--------+-------- Percentage of | | | | | | nitrogen in | .168 | .092 | .064 | .189 | .134 | .089 dried soil | | | | | | Equal to | | | | | | ammonia | .198 | .112 | .078 | .229 | .162 | .108 --------------+--------+--------+--------+--------+--------+-------- “This difference in the amount of accumulated nitrogen in clover-land, appears still more strikingly on comparing the total amounts of nitrogen per acre in the different sections of the two portions of the 11-acre field. Percentage of Nitrogen Per Acre.