FLORIDA STATE HORTICULTURAL SOCIETY 
57 
formation of vegetable matter into humus, 
assists in the retention of humus against 
the oxidizing effects of hot climates, and 
prevents the loss of humic acids by pre¬ 
cipitating them into beneficial lime hu- 
mates. Also, lime corrects the toxic ef¬ 
fect of many compounds that accumulate 
in an acid soil—as proto-sulphate of iron 
and certain other poisonous compounds. 
As to the biological effects of liming 
soils, there are the direct and indirect ben¬ 
efits. Calcium, the active basic element 
in lime, is a direct plant food, and all 
plants require a certain small amount to 
build up their tissues. It enters largely 
into the formation of the cell walls in the 
growing tissues of the plant and aids in 
the formation of feeding roots. Citrus 
trees require it, and remove a small 
amount from the soil each year. Every 
carload of three hundred boxes of oranges 
carries away one hundred pounds of lime, 
and the ash of the citrus tree contains 
about 6 per cent of lime. 
There is also the factor of the lime- 
magnesium ratio which at the present time 
is a bit uncertainly established. It is suffi¬ 
cient to say that the lime content of the 
soil should exceed twice the magnesium 
content. 
It has also been observed by a number 
of growers throughout the state that lime 
tends to give a smoother skin and brighter 
color to the oranges, grapefruit and tan¬ 
gerines. 
Certain plants are benefited by lime, as: 
Lettuce, beets, okra, celery, onions, cauli¬ 
flower, cucumbers, cow peas, eggplants, 
cabbage, cantaloupe, pepper, peanut, tur¬ 
nip, common pea, pumpkin and squash, 
sorghum, alfalfa, clover, velvet bean, 
wheat, orange, grapefruit. In experiments 
with these crops not only were the yields 
greater in many cases, but they were ready 
to be marketed much earlier where the 
soil had been limed. Among the plants 
which have shown a slight injury from 
liming under certain conditions and may 
under other circumstances be helped by it 
are: Cotton, tomatoes, peach, apple and 
pear. 
The plants which have quite persist¬ 
ently shown marked injury are : Common 
sorrel, radish, blackberry, raspberry and 
cranberry. The influence of lime on some 
plant diseases is also important. Lime 
tends to favor the production of potato 
scab, provided the germs of the disease 
are already in the soil or are introduced 
into it on the seed tubers. 
On the other hand, liming is capable of 
lessening materially the injury to turnips, 
cabbage, etc., caused by the disease known 
as finger-and-toe or club root. 
Slaked lime was found to be effective in 
reducing soil rot of sweet potatoes, and 
quick lime in checking or preventing the 
root disease of alfalfa. 
But one of the chief effects of lime is 
the favorable influence it has on the activ¬ 
ities of soil micro-organisms and bacteria. 
“Many important changes are produced 
in the soil by organisms so small that they 
can only be observed by the aid of the 
most powerful microscopes, and these or¬ 
ganisms are the life of the soil. Some of 
the changes of this character in which lime 
plays an important part are the following: 
(i) The change of ammonia and of ni¬ 
trogen in organic matter such as blood, 
