alcohol, add :i drop ,,f n HHI lt,; iT, \
tU* until neutral \m\ i |tl i u ..
(or an cquivMfei f v< }Uiii» t • „,. i ,,
and add, dropwise arid with « ,M • -4 • .*
solution of barium chloral* t,, pro pit i
boiling until the prwipituto *» ttl* - n
barium sulphate and \\ath \\nli i,.»t \u>tt
fully burn the paper in an indmtd ITU'
white but do not allow the indhlt t > ><
longer than is necessary to burn a'a ^
sulphur in the soil, expressing as the element
Lime Requirements of Soils.—Lime ^ ad(k\I n a<-«I ^"*:^ A^
the purpose of neutralizing their exeex- of a<';«i i -r J J!M» :- i *zi -
the physical texture of the soil. la atMiti* ?i ti th* ^ t£r t-,
there is a precipitation of iron ami aluiiiini<ini :u»iri -ouibk >^>^
as hydroxides, in this way lessening their toxicity.
Calcium itself is regarded as one of the necessary elements
in the plant economy. There is considerable difference with
regard to the need of different plants for calcium and also with
respect to their ability to draw this element from the less available
sources. Alfalfa Is an example of a that needs inndi cal-
cium in its metabolic processes but having a rather limited feed-
ing power while, on the other hand, the rye plant much ^
less calcium but possesses ample feeding capacity to secure the t'f{i
little it requires. , ']
«
It is generally considered that many soils possess acidity
through the presence of insoluble acid salts of organic ami I>!
inorganic acids and a number of methods in use for the deter- I *
inlnation of soil acidity are based upon this assumption. Certain 'f ^
fertilizers have a tendency to cause a soil to become acid. This \, f»
is especially true of ammonium sulphate. As nitrogen Is taken >,( \
from this salt by the plant, sulphuric acid remains as a \^\
residue in the soil. Green manures have been credited also with £J \
producing acid soils, acid being formed during fermentation. I| |
However, much confusion still exists concerning the true nature //j |
of soil acidity and consequently there is no generally accepted ^ f
method for its determination. The lime calculated to be { ^
required to neutralize acidity varies, therefore, according to the
method employed for the determination of acidity.