THE HOOS FIELD BARLEY SOILS. 
151 
namely, plat 04, which is so fertile in the growth of the Leguminous 
w<mm1 to which attention has been directed. 
If we take the three depths (27 inches in all), we find that this plat 
shows over 21 pounds of nitric nitrogen per acre. 
The poorest plat in nitric nitrogen is t ho plat which produces the 
smallest erops (Ol). This contains less than 16 pounds of nitric 
nitrogen per acre in the three depths; plats ( >:> and 04 being inter- 
mediate. 
If plat ot (the leguminous-wood plat) be left out of account, we 
see that the plats manured with ammonium salts and with sodium 
nitrate (sect ions A and AA) are uniformly richer in nitric nitrogen 
than those of section (). But much richer in nitrates are the surface 
soils and higher subsoils of the rape-cake section, owing to abundant 
nitrification of accumulated nitrogenous organic matter. Richer still 
are t lie dunged plats. Plat ~ (1) contains nearly 15 pounds per acre 
of nitric nitrogen per aero in the surface soil (nearly l| pounds more 
than any of the undunged plats), and is as rich as even the rape-cake 
plats in the second depl li. and decidedly richer than even these in the 
third depth. The cont inuouslv dunged plat is much richer in the 
surface depth, and also in the second depth, and 0.1 pounds per acre 
richer in the l'7 inches. It would scarcely have been expected, even 
in the ease of the continuously dunged plat, that so much nitric 
nitrogen would be found in February and March. 
On the wheat plat similarly treated, only ~>'*> pounds of nitric nitro- 
gen per acre were found in ( )ctoher in the first is inches of soil. Here, 
in February and March, we ha\ e 33 pounds, or half the quantity, not- 
withstanding a wet winter. This would seem to indicate that nitrifi- 
cation must have begun early. On the other hand, the accumulated 
organh matter in the dunged soil must, by its absorptive power, render 
the dunged land less suscepi ible, pro rata, to loss by drainage, than the 
undunged plats, more of the rainfall being retained and dispersed by 
surface evaporation. On the IJroadbalk plats, which are, as we know, 
pipe drained, the drainpipes often run freely on the undunged plats, 
while those on the dunged plats are giving no drainage water. • 
CHLORIN. 
In the O series, without nitrogenous manure, the chlorin is greater 
in the superphosphated plats, Nos. '2 and 4, than in the others, the 
difference being especially marked in the third depth. The same 
thing is seen in the A series (ammonium salts). The explanation of 
this is not obvious. It can not be found in the introduction of chlorids 
to the soil, for the difference between the two sets of plats in chlorin 
contents is not great, although the O plats receive no direct addition 
of chlorids, except as slight impurities in the mineral fertilizers, 
beyond those derived from rain; while the plats of the A series 
