Garden Chemistry in Soil Cultivation 
By William S. Gill 
TO the lover of gardening any science which has a 
direct bearing on his craft mnst be interesting 
and worthy of study, and none more so than the 
science of chemistry. Chemical action, as we may term 
it, permeates the whole system of garden life and goes on 
without interruption and without rest. This is espe- 
cially true of soil, and the reason for soil cultivation is 
to promote that action in the way best calculated to assist 
the soil to the greatest degree of fertility. For the pur- 
poses of this paper I will class soil cultivation under three 
heads, i. e., Drainage, Working the Soil and Manuring. 
Where a soil is waterlogged or soggy draining be- 
comes a necessity. Air cannot permeate soil in that con- 
dition, and it takes so much longer for that soil to be- 
come warm. Warmth and air are absolutely necessary 
for the living organisms of the soil, and without these a 
high state of fertility cannot be attained. A cold, wet 
soil is for that reason a poor rooting medium, and drain- 
ing must be undertaken to correct that condition. 
Under the head, Working the Soil, is included plough- 
ing, digging, trenching, harrowing and hoeing. The first 
three are various forms of one operation, i. e., opening up 
the soil and exposing it to the air and securing a deeper 
rooting medium. Where large areas are to be cultivated 
ploughing is the only practicable way, and for farm 
crops this provides a satisfactory method. In the garden 
digging and occasional trenching are possible, and these 
give us a greater depth of mellow, aerated soil and make 
possible the production of high class garden produce. 
Harrowing serves to break up the coarse lumps and 
clods, thereby insuring better aeration and greater con- 
servation of moisture for the roots. The finer the grains 
of soil the better is moisture conserved and the sweeter 
the soil is kept. Hoeing and cultivating produce this 
required eflfect. 
It is in the practice of manuring that a knowledge of 
chemistry comes most useful. The old meaning of the 
word manure — to till by • hand — would not cover the 
present day use of the word, and it is now accepted to 
mean the application of dung or chemical fertilizers. It 
is very necessary to get the full benefit of manuring that 
lime or chalk be present in sufiicient quantities in the 
soil. E.xcept for growing a few subjects — such as Rho- 
dodendrons, Azaleas, etc., to which lime is a poison — all 
soils require the presence of lime to insure fertility. Lime 
counteracts sourness of the soil, and is absolutely neces- 
sary in the preparation of plant food. 
Dung in some form is probably the manure which is 
most largely used. It contains nitrogen, potash and 
phosjihate in varying quantities, according to its origin 
and storage. 
Pigeon and poultry dung are the richest, and for this 
reason require caution in application. Sheep manure is 
rich in nitrogen. Horse manure is richer than cow, but 
more liable to loss in keeping. Dung should not be ap- 
plied to the soil until it has been stored for a time. If 
kept in a heap it requires frequent turning to keep it in 
good condition and prevent loss of its valuable properties. 
Dung is also valuable as a means of providing organic 
matter or humus to the soil. Humus or decaying vege- 
table matter helps a light soil to retain moisture and 
makes a heavy soil lighter and more workable. In its 
decomposition" it gives ofif carbonic acid, which is useful 
as a potash solvent, and with lime it acts to retain am- 
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monia in the soil. Mulching with dung is a common 
practice and, providing it is not done too early in the 
sprmg before the soil is properly warmed througlt, has 
much to recommend it. It should not be applied too 
heavily or be of such a close texture as to exclude all air 
from the soil. 
Many chemicals necessary to plant growth occur in 
sufficient quantity in most soils, and the three chief ex- 
ceptions are nitrogen, phosphate and potash, and of these 
the first two are the most easily exhausted.. ■ l^Jitrogenous 
manures have the efl:'ect of stimulating leaf and stem 
growth. Nitrate of soda and sulphate of ammonia are 
the two most widely used forms of this manure. 
Nitrate of soda is very soluble in water and is quickly 
available for plant food. Where quick results are de- 
sired the use of this manure has much to recommend it. 
It cannot be retained long in the soil and therefore small 
and frequent applications should be the rule. 
Sulphate of ammonia is, to my mind, much to be pre- 
ferred for genera! use. It can be applied in spring and, 
contrary to nitrate of soda, will be retained in the soil 
and liberated gradually as nitrate all the season. 
Nitrogen in the soil must be changed into nitrate be- 
fore it isavailable for plant food, and this is the work of 
niinute living organisms in the soil, sometimes called 
nitro-bacteria. This knowledge has been turned to ac- 
count in the preparation of bacteria cultures, which are 
put on the market under various names. For inoculating 
the seed or soil for legumes these cultures can be profit- 
ably used. Especially with alfalfa has this method been 
used with great success. 
Phosphatic manures have the property of stimulating 
and assisting flower and fruit production. Superphos- 
phate or acid-phosphate is the most popular form of this 
manure, and an application of this in the spring would 
be of great benefit to most gardens. In the use of this 
manure much may be accomplished in securing a well 
balanced growth in fruit trees and lessening the labor 
of pruning — both root and branch — which is the result 
of too much nitrogen. 
F)One meal is a phosphatic manure and is liest used 
where it is desired to provide phosphate for a long 
period. For applying to the soil previous to planting 
fruit trees or in making up vine borders it is to be 
recommended. 
Basic slag is a valuable form of applying phosphate to 
the soil. This is best applied in fall to reap the full bene- 
fit the following season. Unless the soil is chalky this 
is a splendid manure to use, as it contains a large per- 
centage of lime. 
Potassic manures increase cpiality and aid in the stor- 
ing of sugar in fruits. They tend to increase flavor and 
scent. At present the price of potash is prohibitive, and 
it is fortunate that of the chief soil fertilizers potash is 
probably the one that most garden soils are least in need 
of. This is es]iecially true of soils which have been pe- 
riodically treated with dung which contains a percentage 
of potash, as every bit of potash that goes into the soil 
is gradually available for plant food, providing there is 
a sufficiency of lime in the soil. Kainit and sulphate of 
potash are probabl}' the best forms of potassic manures 
for garden use. Sulphate of potash is a refined, concen- 
trated form of kainit. 
At present the best available substitute for the unpro- 
(Cniifiiiitcd on pati^e 34,x") 
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