on Permanent Meadow Land. 
509 
The experiments with nitrate of soda (Plots 6 and 7) were 
commenced two years later than those with the other manures, so 
that we have the results of only five instead of seven years to record. 
Unlike those with ammonia-salts alone, however, we have, so far, 
indication rather of progressive increase than decrease of annual 
effect. There is also, as yet, rather more of produce and increase 
from a given amount of nitrogen applied in the form of nitrate 
of soda (Plot 7), than fi-om an equal amount in the form of 
ammonia salts (Plot 4). The description of plants developed 
was, moreover, very different in the two cases. These results 
may be partly due to the fact that the soil having less power to 
absorb and retain the nitric acid of the nitrate than the ammonia of 
the ammonia-salts, the former would probably be more rapidly 
diffused in the soil, and hence minister to the wants of plants 
whose roots take a wider range than those of the plants most 
benefited by ammonia salts. 
The experiments with superphosphate of lime alone (Plot 3a), 
and with superphosphate of lime and ammonia-salts (Plot Sb), 
were commenced three years later than most of the others, so that 
the results recorded refer to the produce of four years only. 
The average annual increase with the superphosphate of lime 
alone was little more than 2 cwts. of hay per acre ; and the produce 
has fluctuated, from year to year, much in the same degree as 
that without manure, excepting that in the fourth season (1862) 
the produce scarcely exceeded the average without manure. 
The addition of ammonia-salts lo superphosphate of lime, 
raised the average annual produce from 28 J cwts. to 43|^ cwts., 
and the average annual increase beyond the produce without 
manure from a little more than 2 cwts. to nearly 17 J cwts. 
When to superphosphate of lime, salts of potass, soda, and 
magnesia were added (Plot 8), the average annual produce was 
raised from 28J cwts. to 36J cwts. of hay per acre ; but the in- 
crease under these circumstances consisted almost wholly, if not 
exclusively, of Leguminous plants — clovers, meadow vetchling, 
and bird's-foot trefoil. Both the average produce and average in- 
crease were rather higher during the last four years than over the 
whole seven years of the experiments, and there is as yet no sign of 
diminution. In fact, this "mixed mineral manure" supplied 
annually more of all the mineral constituents otherwise most 
iikely to be exhausted than would be taken off in the increased 
produce of Leguminous plants. 
The addition of sawdust to the mixed mineral manure (Plot 9) 
scarcely added at all to the produce. It should be observed, in 
regard to the manuring of this plot, that in 1862 the potass-salt 
was omitted, and a larger quantity of soda-salt substituted, and 
the result was (as shown in the last Number of the Journal) 
