LIMING OF SOILS FROM A PHYSIOLOGICAL STANDPOINT. » 33 
From all these considerations we can infer that for the culture of 
the sugar beet one of the many conditions of success Is a magnesia 
content nearly equaling the lime content of the soil. 
Numerous manuring experiments have been made, with more or less 
success, to ascertain the best development of the sugar beet to insure 
the maximum production of saccharose. Some attention should also 
be paid to the regulation of the ratio between lime and magnesia in 
the soil, as this may prove of great importance. 
CORRECTION OF LIME AND MAGNESIA CONTENT IN SOILS. 
Although there are crops which require a relatively large amount 
of magnesia when roots, tubers, and seeds are richer in magnesia than 
in lime, yet the entire plants of any crop require more lime than mag- 
nesia, since the stalks and leaves show a preponderance of lime; hence 
such soils would, other things being equal, be best adapted for agri- 
cultural purposes which show a preponderance of Jime over magnesia, 
at least in the finer particles available to the plant roots. The amounts 
of lime and magnesia, in kilograms, extracted from one hectar (nearly 
2.5 acres) of ground by various plants in one year’ are in average as 
follows: 
Lime and magnesia extracted from soil by various plants. 
Plants, ete. Lime. Magnesia. 
Kilograms. Kilograms. 
ERE S Tendo ek ee oie a Se ee a ee 16 10 
oP ST Teens hs5: oo el. 22 ee ee ee 30 15 
UST Se agate ee oe ee ee ee 40 20 
“DER DT TO DF ate bie. ek ee ee 40 27 
iO Pe a Se see SS ee ee ee ee 46 17 
(VERE ee et Sie 4 See ys 50 12 | 
STDS Wf ee eee 7 se) 
Since, however, the roots come into direct contact with only a rela- 
tively small portion of the soil, the absolute amount of available lime 
and magnesia must be very much greater than would follow from the 
data in the table. 
The review of soils above given leaves no doubt that lime prepon- 
derates over magnesia in most soils, and that the very best soils show, 
among other advantages, this peculiarity. But, nevertheless, cases are 
not infrequent in which the amount of magnesia is larger than that of 
lime. As long as this excess is only moderate no evil effects may be 
noticed, but they become evident when this relative excess is consider- 
able. A correction of the soil by liming for the physiological needs of 
the crops will then be in order. The nature of the crops and the depth 
to which the roots penetrate will serve as a basis for the extent of 
1 Ebermayer, Chemie der Pflanzen, Vol. I. 
4784—No. 1—01——3 
