254 
Journal of Agricultural Research 
Vol. IX, No. 8 
inorganic plant constitutents. An economic bearing is also given to the 
investigation by the fact that the mulched-basin system has in some 
cases had a marked effect in reducing mottle-leaf on Citrus trees. 
The present paper deals with the solvent action on certain inorganic 
soil constituents of the water-soluble decomposition products of manures 
and other organic fertilizers. Soils were extracted (a) with soluble 
organic matter obtained from decomposing green manures and from 
stable manures; (6) with soluble organic matter obtained from thor¬ 
oughly decomposed green manures; ( c) with artificially prepared humus 
solutions obtained by hydrolyzing organic substances with acids; and 
(d) with osmosed organic solutions derived from the decomposition of 
organic matter. In addition, stable and green manures were added 
directly to the soil and the effect of this treatment was noted (a) on the 
amounts of certain soil minerals dissolved out with water, and ( b ) on the 
change produced in the specific electrical conductivity of the soil. 
METHOD USED IN DECOMPOSING ORGANIC SUBSTANCES 
Green barley hay, sweet clover, and alfalfa were dried and chopped 
into small pieces, and 70 gm. of each of these substances were placed in 
separate large bottles, moistened to saturation with distilled water, and 
allowed to ferment. An equal amount of dry cow manure was similarly 
treated. Fourteen days later these four substances were shaken up 
thoroughly with 1,500 c. c. of distilled water each and the coarser material 
filtered out through muslin. This filtrate was then passed through a 
Chamberland porous filter and collected. The solid organic matter 
from each of the four substances was returned to its respective bottle, 
kept saturated, and at a later period was again shaken with distilled 
water as above, filtered, and the filtrate again collected. The organic 
solutions thus obtained were used for soil extraction. 
Table I .—Intervals between successive extractions of green manures 
No. of 
extract. 
Date 
extracted. 
Number of 
days since 
placing in 
bottles. 
Number of 
days since 
preceding 
extraction. 
I. 
Feb. 
2 
14 
2. 
Feb. 
24 
36 
22 
3 . 
Mar. 
IS 
55 
19 
4 . 
Apr. 
25 
96 
41 
These organic extracts were entirely free from suspended matter. The 
intervals between extractions are given in Table I. The organic solutions, 
or solvents, 1 were added to the soils under investigation in the propor¬ 
tion of 250 gm. of soil to 500 c. c. of solvent. 
1 In order to avoid confusion in the mind of the reader, the term “solvent” will be used in speaking of 
the organic extracts obtained from the various organic substances, and which are used in making soil 
extracts. Relative to the soil, they are solvents, though in themselves they are systems of water-solvent 
and organic and inorganic solutes. 
