334 
MESSRS. J. B. LAWES AND J. H. GILBERT ON THE RESULTS OF 
period compared with the first, there is, under the influence of the nitrate of soda, 
an increase in each of the three items over the later period. 
When considering the effects of the two nitrogenous manures used alone, attention 
was called to the fact that the nitrogen of the nitrate of soda distributed much more 
rapidly through the soil than that of the ammonia-salts (p. 306), and that, coincidentlv, 
not only were those plants favoured by the nitrate which could the most rapidly take up 
the supplies near the surface, but those also which had a tendency to distribute their 
roots in the deeper layers ; and hence, under them influence, there was a greater 
development of root in the lower layers, and with this the growing herbage acquired 
possession of wider and deeper ranges of soil and subsoil. 
This was strikingly illustrated in the results obtained on the two plots now under 
consideration (14 and 9) in the season of drought of 1870. In that year the produce 
of hay on plot 9, with the mixed mineral manure and ammonia-salts, was nearly 
23 cwts. below its average amount, whereas on plot 14 it was less than 1^- cwt. below 
its average. In view of this extraordinary difference of result from the same mineral 
manure and the same amount of nitrogen applied, not only the description of plants 
grown, but the distribution of the roots was examined ; and samples of the soils were 
taken, every nine inches, down to a depth of 54 inches, on these and on the unmanured 
plot, for the purpose, among others, of determining the amount of moisture remaining 
in the soil at the different depths. 
The following table shows the percentage of moisture (as determined by drying at 
100° C., and including the loss by evaporation during preparation for analysis) in the 
samples of the different soils at the different depths. 4 ' 
Table XIII.—Samples of soil collected July 25-6, 1870. 
Depth of sample. 
Per cent, moisture. 
Plot 3. 
Without 
manure. 
Plot 9. 
Mineral manure 
and 
ammonia-salts. 
Plot 14. 
Mineral manure 
and 
nitrate soda. 
First nine inclies . 
10-83 
13-00 
12-16 
Second nine inclies . 
1334 
10-18 
11-80 
Third nine inclies . 
19-23 
16"46 
15-65 
Fourth nine inches . 
22-71 
18-96 
16-30 
Fifth nine inches . 
24-28 
20-54 
17-18 
Sixth nine inches . 
25-07 
21-34 
18-06 
Means .... 
19-24 
16 - 75 
15-19 
Now, if we assume, as is sufficiently near the truth for the purpose of illustration, 
that down to the total depth of 54 inches an acre of the soil would weigh (exclusive 
* See “ Effects of tlie Drought of 1870 on some of tlie Experimental Crops at Rothamsted.” (Jour. 
Roy. Ag. Soc. Eng., vol. vii., S.S. Part I.) 
