071 Pennanent Jfeadbrc Land. 
513 
obtained by the most active artificial manures. The descrip- 
tion of herbage was, however, very different — that grown by 
the farmyard manure being very much more complex and, upon 
the whole, superior in quality to that grown by the very active 
artificial Manures. 
The addition of 200 lbs. of ammonia-salts to the comprehen- 
sive, but not verv rapidly active, farmvard manure increased the 
average annual produce by only about 6 cwts. of hay ; still, 
therefore, giving a produce considerably less than that obtained 
by the most active artificial manures. Nor did the addition of 
ammonia-salts improve the character of the herbage, which was 
more Graminaceous, consisted in larger proportion of compara- 
tivelv few species, and was much more stemmy, than when the 
farmyard manure was used alone. The number, and proportion 
in the produce, of miscellaneous or weedy plants was, however, 
considerably reduced under the influence of the ammonia-salts. 
Reviewing the results of the whole series, it is observed that 
the average produce without manure is slightly higher over the 
last four than over the whole seven years of the experiments ; 
indicating, therefore, that the conjoint resources of soil and 
season were at least equal, if not more favourable, during the 
later years. A similar result is observed in the case of the farm- 
yard manure plot, and of the plots where there was a liberal 
supply of mineral constituents without ammonia in the artificial 
manures ; but where ammonia-salts Mere used in large quantity, 
either alone or in conjunction with the mineral manures, there 
was a tendency to a rather diminished rate of increase as 
the experiments proceed. The indication, so far as the gross 
amount of hay obtained is concerned, is, however, as yet but 
slight ; and in the present season (1863) the produce on Plot 13a, 
where the very excessive amount of ammonia-salts was used, 
and where the mineral manure contained no silicates, is heavier 
than in any previous season. The chief indication of exhaustion 
of certain constituents, or of deterioration of the produce, is 
afforded by a consideration of the description and composition 
of the herbage developed. Where nitrate of soda is used, whether 
alone or in conjunction with the mixed mineral manure, there 
is as yet no evidence of progressive falling off in the annual 
yield. . 
Produce of After-Grass. 
Table II. (p. 531) shows the amounts of hay per acre to which 
the after-grass of each of the last four seasons is estimated to be 
equivalent, and also the annual average over the four and over the 
seven years of the experiments. As already mentioned, the after- 
grass was always consumed by sheep (once or twice, as might be 
2 L 2 
