The Bistory of a Field newly laid doivn to Permaneni Gh-ass. ^ 
there is much drainage. Under similar conditions, there may 
also be more or less loss from the soluble nitrogenous portion of 
dung. It is probable, however, that, in the case of the mixed 
herbage of grass-land, with a great variety of plants, hnving 
widely different root-ranges and habits of growth, and with vege- 
tation going on to a greater or less extent almost the whole year 
round, there will be much less loss of nitrogen by drainage, even 
from artificial manures, than when they are applied to aia'ile 
land — especially when such small quantities are used, ana at 
the commencement of the active growth of the season, as in the 
case now under consideration; whilst it maybe doubted whether 
there will generally be any material loss of nitrogen by drainage 
from farmyard manure or town dung applied to grass-land. But 
when dung is applied in excessive quantities to arable land, or to 
soil which becomes water-logged and is not sufficiently aerated, 
there may be more or less loss by the evolution of free nitrogen. 
Changes within the Soil in the Formation of the Meadow. 
Before discussing the experimental results obtained, relating 
to the changes which have taken place in the condition of the 
land during the formation of this particular meadow, it will be 
well to direct attention, in general terms, to the main distinctions 
between the soil of arable land and that of permanent grass. 
If we examine arable land after the removal of a grain crop, 
we find that the amount of roots left in the soil is very small. 
Thus, in a case in which a large crop of barley had been grown, 
four samples of soil were taken, each 12 inches square and 
9 inches deep, and from each the roots were very carefully sepa- 
rated. The calculation of the results showed an average of only 
536 lbs. of roots per acre in the surface-soil to the depth of 
9 inches. Of above-ground residue, or stubble, there was on the 
average 1,104 lbs. per acre. The nitrogen in the stubble and in 
the roots of the surface-soil, taken together, amounted to oiily 
about 8^ lbs. per acre. Where, in the same field, clover had 
grown, there was, on the other hand, an average of 3,107 lbs., or 
nearly 1 ton 8 cwts. of roots per acre, in the first 9 inches of 
depth ; and there was 2,669 lbs., or nearly 1 ton 4 cwts., of above- 
ground residue ; and the nitrogen in the two together was more 
than 90 lbs. per acre. There was, besides, a greater amount of 
roots, and of nitrogen in them, in the second and third 9 inches 
than in the case of the barley-ground. 
When land is laid down to permanent grass the seeds are 
more frequently sown with barley than with any other crop ; 
and afler a certain number of years, greater or less according to 
