Afi’TANf AGES AND DISADVANTAGES OP SUBSOIL AND TRENCH PLOWING, ETC. 
107 
ADVANTAGES AND DISADVANTAGES OF 
SUBSOIL AND TRENCH PLOWING. 
Subsoiling, we are to understand, consists of 
loosening the ground below the depth it is ordina¬ 
rily disturbed by common tillage. A heavy plow 
is first run along the field, say from six to ten 
inches deep, and is then followed, in the bottom of 
the same furrow, by a subsoil plow, which has no 
mould board, stirring the soil to a depth of six or 
eight inches more. 
The reasons generally slated in favor of this 
system, by its advocates, are the follow¬ 
ing:—1st. That where there are drains in a field, 
subsoil plowing facilitates the escape of water into 
these drains. 2d. It deepens the actual thickness 
or amount of soil to the extent of from eight to six¬ 
teen inches; thereby affording double nourishment 
to the crops. 3d. It increases the heat or tempera¬ 
ture by lessening evaporation. 4th. In dry sum¬ 
mers, when crops are parched, the increased thick¬ 
ness of soil, which causes the roots to penetrate to 
a greater depth than usual, enables the crop to 
withstand the drought. 
The chief objections urged against subsoiling are, 
1st. The extra labor of men and horses. 2d. From 
the tardiness of the operation, it drives out of sea¬ 
son the other work of the farm. 3d. On light, 
leachy soils, it is attended with little or no benefit, 
but on the contrary, is injurious in causing rains 
and liquid manure to descend more readily beyond 
the reach of the roots of the plants. 
By trench 'plowing , the soil is cast up to the sur¬ 
face, and is either benefitted or injured thereby, ac¬ 
cording to the nature of its constituents and the 
manner in which it is trenched, after it is turned up. 
For instance, there is often contained in subsoils, a 
considerable proportion of matter, called by chem¬ 
ists, protoxide of iron , which is readily dissolved 
by rain water, and in that state, is poisonous to 
plants, if directly applied to their roots; but if 
these subsoils are opened to the influences of the 
atmosphere, this substance will gradually be con¬ 
verted into peroxide of iron (common red iron rust), 
and may be applied to crops without injury. It 
often happens, also, that some subsoils embrace 
fragments of rocks containing sulphur combined 
with iron (sulphuret of iron), which, on exposure to 
the atmosphere, is changed into green vitriol or 
common copperas (sulphate of iron), and in that 
state is quite as unfit for the food of plants as the 
protoxide of iron. Both of the two last-named salts, 
however, when brought into contact with lime, or 
any of the alkaline carbonates, are easily decom¬ 
posed, changing the iron into a peroxide, which is 
not only harmless to plants, but in some cases bene¬ 
ficial to them. The sulphuric acid, contained in the 
copperas, also, at once combines, in definite pro¬ 
portions, with the lime, or other alkaline bases, 
spread upon the soil, and forms in one case, sul¬ 
phate of lime (gypsum or plaster), and in others, 
sulphates of soda, potash, &c., according to the na¬ 
ture of the alkaline carbonate applied, the fertilizing 
influences of which are too well known to require 
repetition here. Hence, the good effects which often 
occur from abundant top-dressings with air-slacked 
lime, or of wood ashes, carbonates of soda, potash, 
&c., on land that has been trenched or deeply plowed. 
If a soil be sandy, gravelly, or light, with little or 1 
[ no sod on its surface, or vegetable matter beneath, 
j no particular advantage will result from trenching, 
unless there be plowed under a liberal supply of coarse 
barn-yard manure—green clover, vetches, buck¬ 
wheat, or weeds—-dry leaves, grass, stubble, straw, 
or some compost rich in animal and vegetable salts; 
and then it will often become necessary to add a 
slight top dressing of guano, poudrette, or some 
stimulating manure, in order to give vigor to the in¬ 
fant plants. But if the upper soil be deep, and is 
interwoven with the roots of grass, weeds, &c., it 
may be turned under to a depth of ten inches 
to a foot ) and so long as this vegetable matter re¬ 
mains in the soil, it will serve as a proper 
food for other plants. In short, if due atten¬ 
tion be paid to the application of plaster, lime, 
ashes, vegetable and animal manures, if the ground 
be hot and sandy, trench plowing will make it cool 
and moist * and if it be strong and clayey, it will 
open it and keep it loose, rich, and mellow. 
For an interesting article on pulverization of the 
soil, see page 196 of our sixth volume. 
AGRICULTURE OF THE CHINESE.—No. 4. 
Hemp , or Ma , and Other Fibrous Productions .— 
Among the fibre-bearing plants of China, there is a 
species of urtica [ma], both wild and cultivated, 
that grows from one to two yards in height, and 
produces a strong fibre, in the bark, which is pre¬ 
pared by the natives, and sold for the purpose of 
making cable and ropes. ( a) 
Another strong fibre is obtained from the bracts 
of a palm tree, cultivated on the hill sides of 
Chusan, as well as in similar situations all over the 
province of Chekiang. These articles answer the 
purposes to which they are applied extremely well; 
but the ropes made from the Manilla hemp is of much 
greater strength and durability. ( b ) From the 
bracts of this same palm, the natives of the north 
make what they call a so-e , or garment of leaves, 
and a hat of the same material, which they put on 
during rainy weather; and although they look 
comical enough in the dress, still it is an excellent 
protection from wind and rain. In the south of 
China the so-e is made from the leaves of the bam¬ 
boo and other broad-leaved grasses. 
(<z) The ma, if we can rely upon the account of 
Tingqua’s “ Outlines,” illustrating the cultivation 
of hemp and the manufacture of grass cloth, as 
published in a late number of the Chinese Reposi¬ 
tory, may be found in almost every description of 
fabric—in the largest cables of the junks, and even 
in the choicest textures of clothing, worn by the 
luxurious classes. Like silk, it is an article of uni¬ 
versal consumption with the Chinese. 
This plant is represented as an annual, of easy 
production, sown in February, and gathered in Au¬ 
gust. It grows on dry, hilly soil, like tea, in every 
variety of climate, all over the empire, and may be 
cultivated in a similar manner as the common hemp 
is with us. The seed is carefully collected, dried 
in the sun, and put up closely in jars, in order to 
preserve it from injury, in which state, it is probable 
it might be brought to this country, without losing 
its power of germination. We would, therefore, 
recommend that some of cur agricultural friends, 
who are engaged in the China trade, procure a small 
