THE HRdADHALK WHEAT SOILS. 
73 
attributable to the creeping upward, under i he influence of hot weather, 
of nitrates which may liave been washed down earlier. 
Up to 1884, plate 9a and 9b received twice the quantity of sodium 
nit rate that they had received for the nine years immediately prior to 
1*93, so that the greater accumulation of erop residue in plat 9a is no 
doubt partly attributable to more liberal treatment in the past. 
Plat it!) gets the same dressing of sodium nit rate as plat 9a, but with- 
out any mineral manures, and gives naturally much poorer crops year 
[by year. Consequently it is poor in organic crop residues. In the 
first 27 inches it contained, in L893, 6H pounds of nitric nitrogen per 
acre, or I'.t pounds more than its brother plat 9a. Unlike the case of 
9a, most of the nitric nitrogen is found in the second ami third depths. 
It seems that in plat 9a more of the applied nit rate has been used and 
jess washed into the second and third depths. On plat 9b, jrherethere 
Is less Utilization, we find much Of the residue of the unused nitrate 
in thesubsoil: but in the surface soil, at this late period of the year 
(October), there is less nitric nitrogen, possibly because there is less 
crop residue and less oxidation. Doubtless, if we had samples of the 
lower dept lis we should find much more nitrate that lias been wasted 
for lack of mineral food to enable the crops to take it up. 
As may be seen hereafter, the analyses of the soils of these two 
plats in 1881 showed very similar results, as was very clearly pointed 
out to you in Professor Warington's Lectures dealing with the subject 
of nit i i licit ion. 
When we turn to plats 7 and L6, similarly manured to plais 6 and 
9a, but with twice the quantities of ammonium sails and of sodium 
nitrate, respectively, we find not a great deal of difference in the suf- 
fice soil. In the subsoil, however, we find in the second 9 inches 
more than twice as much nitric nitrogen on the nitrated plat Idas on 
the ammonia-manured plat. 7, and about-.' t hues as much in the third 
depth. Then we have a great decrease as we pass the level of the 
drainpipes; still the fourth depth contains about times as much on 
plat 1 <") as on plat 7, and alt hough t he difference becomes then less, there 
is much more nitric nitrogen in each succeeding depth as far as we 
go. In the first -7 inches plat 1(5 contains about 34 pounds more 
nitric nitrogen per acre than plat 7, and in 7i } inches aboul 50 pounds 
more, equivalent to about 3 hundredweighl of commercial nitrate of 
soda ; a good deal of w hieh nit ric nit rogen has sunk too low for 1 here 
to be much hope of its future recovery, and is as virtually lost as 
though it had escaped by way of the drainpipes. It should be men- 
tioned that t he crop on plai L6 was very poor, having been injured by 
so heavy an application of manure in a dry season. 
It is not remarkable, after an annual spring dressing of 550 pounds 
per acre of sodium nitrate, to find a Large quantity of the necessarily 
nnassimilated nitrate in the subsoils, but as somewhat more nitrogen 
is usually assimilated on the nitrated plat than on the ammonium 
salts plat the annual loss of nitrogen must be greater on plat 7 than 
