THE HOOS FIKLD BARLEY SOILS. 
145 
occurs to some extent on all the plats receiving no nitrogenous 
man ure, but especially on plat 04, manured with full minerals. 
Knowing what we do of the habits of the Leguminosa?, we can not 
doubt that the growth of this weed year after year must add nitrogen 
to the soil, and Sir Henry Gilbert is of opinion — and in the light of 
recent knowledge ii would be difficult to dissent from his view — that 
the high nitrogen of the soil of plat <U is to be accounted for by the 
nitrogen storage produced by the constant growth and plowing in 
of this leguminous weed. The other plats on section O — especially 
plat .1 — WOUld also be to some extent enriched in the same way, but 
not to anything approaching t he same extent as plat 4. Plat ()4 had, 
up to L881, produced on an average II bushels ol grain and three- 
fourths hundredweight of straw more than plat Ol', and 4; bushels 
of grain and L] hundredweight Ol straw more than plat O.'J; but it 
produced a> much as'",.; bushels of grain and 2] hundredweight of 
straw per acre per annum more than plat 01. 
We <lo not timl t he same conspicuous difference in produce between 
plate 3 and 5 on the w heat field as between plats Ol and the cor- 
responding plats of tin' barley field. In the former case, for the same 
thirty years, t he fully minerally manured wheat plat without nitro- 
gen only beat the wholly u 1 1 ma n u iv< 1 plat byan average of bushels 
ot grain and lj hundredweight of Straw, while on these barley plats, 
as we have jusl seen, the gain was bushels of grain ami 2j hun- 
dredweight of st raw. 
Plat ()4 contained in 18*1, in the first 9 inches, 400 pounds, 573 
pounds, and 389 pounds, respectively, more nitrogen per acre than 
plats 1, l\ and 3 Ot its own section, in addition to a large quantity in 
the subsoil. The conservation of nitrogen in increased crop residue 
would, it need scarcely be said, account for no such excess as we find 
in plat 04, which we must attribute to the leguminous influence 
aforesaid. 
In the A section, in which ammonium salts are used throughout, 
the crop on plat I (ammonium salts alone) has been greater than on 
any of the O plats, and its proportion of nitrogen is even lower. The 
nitrogen is considerably higher, however, on plats l\ and 4, which 
receive minerals also, being highest on the most fully manured and 
most abundantly yielding plat, No. 1. in the surface soil of which we 
find 0.10% per cent of nitrogen. 
The next two sections A A and A AS, receive annually the same 
quantity of nitrogen as section A, but differ from it inasmuch as the 
nitrogen is supplied in the form of sodium nitrate instead of in the 
foim of ammonium salts. Section AAS is also supplied with sodium 
silicate. Both of these nitrate sections have given on the average 
considerably larger crops than tin ammonium-salts section. Even on 
plat 1, receiving no phosphates or potassium salts, etc., there has been 
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