MANURES FOR POTATOES.
Some time ago, a farmer in Pennsylvania wrote me that he wanted “to
raise a first-rate crop of potatoes.” I answered him as follows through
the _American Agriculturist_:
“There are many ways of doing this. But as you only enter on the farm
this spring, you will work to disadvantage. To obtain the best results,
it is necessary to prepare for the crop two or three years beforehand.
All that you can do this year is to select the best land on the farm,
put on 400 lbs. of Peruvian guano, cultivate thoroughly, and suffer not
a weed to grow. A two or three-year-old clover-sod, on warm, rich, sandy
loam, gives a good chance for potatoes. Do not plow until you are ready
to plant. Sow the guano broadcast after plowing, and harrow it in, or
apply a tablespoonful in each hill, and mix it with the soil. Mark out
the rows, both ways, three feet apart, and drop a fair-sized potato in
each hill. Start the cultivator as soon as the rows can be
distinguished, and repeat every week or ten days until there is danger
of disturbing the roots. We usually hill up a little, making a broad,
flat hill. A tablespoonful of plaster, dusted on the young plants soon
after they come up, will usually do good. We recommend guano, because in
our experience it does not increase the rot. But it is only fair to add,
that we have not found even barn-yard manure, if thoroughly rotted and
well mixed with the soil the fall previous, half so injurious as some
people would have us suppose. If any one will put 25 loads per acre on
our potato land, we will agree to plant and run the risk of the rot. But
we would use some guano as well. The truth is, that it is useless to
expect a large crop of potatoes, say 350 bushels per acre, without
plenty of manure.”
This was written before the potato-beetle made its appearance. But I
think I should say the same thing now--only put it a little stronger.
The truth is, it will not pay to “fight the bugs” on a poor crop of
potatoes. We must select the best land we have and make it as rich as
possible.
“But why do you recommend Peruvian guano,” asked the Doctor, “rather
than superphosphate or ashes? Potatoes contain a large amount of potash,
and one would expect considerable benefit from an application of ashes.”
“Ashes, plaster, and hen-dung,” said the Judge, “will at any rate pay
well on potatoes. I have tried this mixture again and again, and always
with good effect.”
“I believe in the hen-dung,” said I, “and possibly in the plaster, but
on my land, ashes do not seem to be specially beneficial on potatoes,
while I have rarely used Peruvian guano without good effect; and
sometimes it has proved wonderfully profitable, owing to the high price
of potatoes.”
Sometime ago, I had a visit from one of the most enterprising and
successful farmers in Western New York.
“What I want to learn,” he said, “is how to make manure enough to keep
my land in good condition. I sell nothing but beans, potatoes, wheat,
and apples. I feed out all my corn, oats, stalks, straw, and hay on the
farm, and draw into the barn-yard the potato-vines and everything else
that will rot into manure. I make a big pile of it. But the point with
me is to find out what is the best stock to feed this straw, stalks,
hay, oats, and corn to, so as to make the best manure and return the
largest profit. Last year I bought a lot of steers to feed in winter,
and lost money. This fall I bought 68 head of cows to winter, intending
to sell them in the spring.”
“What did they cost you?”
“I went into Wyoming and Cattaraugus Counties, and picked them up among
the dairy farmers, and selected a very fair lot of cows at an average of
$22 per head. I expect to sell them as new milch cows in the spring.
Such cows last spring would have been worth $60 to $70 each.”
“That will pay. But it is not often the grain-grower gets such a chance
to feed out his straw, stalks, and other fodder to advantage. It cannot
be adopted as a permanent system. It is bad for the dairyman, and no
real help to the grain-grower. The manure is not rich enough. Straw and
stalks alone can not be fed to advantage. And when you winter cows to
sell again in the spring, it will not pay to feed grain. If you were
going to keep the cows it would pay well. The fat and flesh you put on
in the winter would be returned in the form of butter and cheese next
summer.”
“Why is not the manure good? I am careful to save everything, and expect
seven or eight hundred loads of manure in the spring.”
“You had 60 acres of wheat that yielded 25 bushels per acre, and have
probably about 50 tons of wheat straw. You had also 30 acres oats, that
yielded 50 bushels per acre, say 35 tons of straw. Your 20 acres of corn
produced 40 bushels of shelled corn per acre; say the stalks weigh 30
tons. And you have 60 tons of hay, half clover and half timothy. Let us
see what your manure from this amount of grain and fodder is worth.
Manures from
50 tons wheat-straw, @ $2.68 $ 134.00
35 tons oat-straw, @ $2.90 101.50
30 tons corn-stalks, @ $3.58 107.40
30 tons timothy-hay, @ $6.43 192.90
30 tons clover-hay, @ $9.64 289.20
14 tons oats (1,500 bush.), @ $7.70 107.80
24 tons corn (800 bushels), @ $6.65 159.60
---------
Total 213 tons $1,092.40
“This is the value of the manure _on the land_. Assuming that there are
600 loads, and that the labor of cleaning out the stables, piling,
carting, and spreading the manure is worth 30 cents per load, or $180,
we have $912.40 as the net value of the manure.
“Now, your 250-acre farm _might_ be so managed that this amount of
manure annually applied would soon greatly increase its fertility. But
you do not think you can afford to summer-fallow, and you want to raise
thirty or forty acres of potatoes every year.”
“I propose to do so,” he replied. “Situated as I am, close to a good
shipping station, no crop pays me better. My potatoes this year have
averaged me over $100 per acre.”
“Very good. But it is perfectly clear to my mind that sooner or later,
you must either farm slower or feed higher. And in your case, situated
close to a village where you can get plenty of help, and with a good
shipping station near by, you had better adopt the latter plan. You must
feed higher, and make richer manure. You now feed out 213 tons of stuff,
and make 600 loads of manure, worth $912.40. By feeding out _one third_,
or 71 tons more, you can _more than double_ the value of the manure.
50 tons of bran or mill-feed would give manure worth $ 729.50
21 tons decorticated cotton-seed cake 585.06
---------
$1,314.56
“Buy and feed out this amount of bran and cake, and you would have 800
loads of manure, worth _on the land_ $2,226.96, or, estimating as before
that it cost 30 cents a load to handle it, its net value would be
$1,986.96.”
I am well aware that comparatively few farmers in this section can
afford to adopt this plan of enriching their land. We want better stock.
I do not know where I could buy a lot of steers that it would pay to
fatten in the winter. Those farmers who raise good grade Shorthorn or
Devon cattle are not the men to sell them half-fat at low rates. They
can fatten them as well as I can. For some time to come, the farmer who
proposes to feed liberally, will have to raise his own stock. He can
rarely buy well-bred animals to fatten. A good farmer must be a good
farmer throughout. He can not be good in spots. His land must be
drained, well-worked, and free from weeds. If he crops heavily he must
manure heavily, and to do this he must feed liberally--and he can not
afford to feed liberally unless he has good stock.
“I have, myself, no doubt but you are right on this point,” said the
Doctor, “but all this _takes time_. Suppose a farmer becomes satisfied
that the manure he makes is not rich enough. To tell him, when he is
anxious to raise a good crop of potatoes next year, that he must go to
work and improve his stock of cattle, sheep, and swine, and then buy
bran and oil-cake to make richer manure, is somewhat tantalizing.”
This is true, and in such a case, instead of adding nitrogen and
phosphoric acid to his manure in the shape of bran, oil-cake, etc., he
can buy nitrogen and phosphoric acid in guano or in nitrate of soda and
superphosphate. This gives him richer manure; which is precisely what he
wants for his potatoes. His poor manure is not so much deficient in
potash as in nitrogen and phosphoric acid, and consequently it is
nitrogen and phosphoric acid that he will probably need to make his soil
capable of producing a large crop of potatoes.
I have seen Peruvian guano extensively used on potatoes, and almost
always with good effect. My first experience with it in this country,
was in 1852. Four acres of potatoes were planted on a two-year-old
clover-sod, plowed in the spring. On two acres, Peruvian guano was sown
broadcast at the rate of 300 lbs. per acre and harrowed in. The potatoes
were planted May 10. On the other two acres no manure of any kind was
used, though treated exactly alike in every other respect. The result
was as follows:
No manure 119 bushels per acre.
300 lbs. Peruvian guano 205 ” ”
The guano cost, here, about 3 cents a lb., and consequently nine
dollars’ worth of guano gave 84 bushels of potatoes. The potatoes were
all sound and good, but where the guano was used, they were larger, with
scarcely a small one amongst them.
In 1857, I made the following experiments on potatoes, in the same field
on which the preceding experiment was made in 1852.
In this case, as before, the land was a two-year-old clover-sod. It was
plowed about the first of May, and harrowed until it was in a good
mellow condition. The potatoes were planted in hills 3½ feet apart each
way. The following table shows the manures used and the yield of
potatoes per acre.
Experiments on Potatoes at Moreton Farm.
P. Number of Plot.
Y/A Yield of Potatoes per acre, in bushels.
I/A Increase of Potatoes per acre, in bushels, caused by manure.
---+-----------------------------------------------------+-----+----
| Description of Manures Used, and Quantities | |
P. | Applied per Acre. | Y/A |I/A
---+-----------------------------------------------------+-----+----
1. | No manure | 95 |
2. | 150 lbs. sulphate of ammonia | 140 | 45
3. | 300 lbs. superphosphate of lime | 132 | 37
4. | 150 lbs. sulphate of ammonia, and 300 lbs. | |
| superphosphate of lime | 179 | 84
5. | 400 lbs. of unleached wood-ashes | 100 | 5
6. | 100 lbs. plaster, (gypsum, or sulphate of lime,) | 101 | 6
7. | 400 lbs. unleached wood-ashes and 100 lbs. plaster | 110 | 15
8. | 400 lbs. unleached wood-ashes, 150 lbs. | |
| sulphate of ammonia and 100 lbs. plaster | 109 | 14
9. | 300 lbs. superphosphate of lime, 150 lbs. sulphate | |
| of ammonia and 400 lbs. unleached wood-ashes | 138 | 43
---+-----------------------------------------------------+-----+----
The superphosphate of lime was made expressly for experimental purposes,
from calcined bones, ground fine, and mixed with sulphuric acid in the
proper proportions to convert all the phosphate of lime of the bones
into the soluble superphosphate. It was a purely mineral article, free
from ammonia and other organic matter. It cost about two and a half
cents per pound.
The manures were deposited in the hill, covered with an inch or two of
soil, and the seed then planted on the top. Where superphosphate of lime
or sulphate of ammonia was used in conjunction with ashes, the ashes
were first deposited in the hill and covered with a little soil, and
then the superphosphate or sulphate of ammonia placed on the top and
covered with soil before the seed was planted. Notwithstanding this
precaution, the rain washed the sulphate of ammonia into the ashes, and
decomposition, with loss of ammonia, was the result. This will account
for the less yield on plot 8 than on plot 2. It would have been better
to have sown the ashes broadcast, but some previous experiments with
Peruvian guano on potatoes indicated that it was best to apply guano in
the hill, carefully covering it with soil to prevent it injuring the
seed, than to sow it broadcast. It was for this reason, and for the
greater convenience in sowing, that the manures were applied in the
hill.
The ash of potatoes consists of about 50 per cent of potash, and this
fact has induced many writers to recommend ashes as a manure for this
crop. It will be seen, however, that in this instance, at least, they
have very little effect, 400 lbs. giving an increase of only five
bushels per acre. One hundred pounds of plaster per acre gave an
increase of six bushels. Plaster and ashes combined, an increase per
acre of 15 bushels.
One fact is clearly brought out by these experiments: that this soil,
which has been under cultivation without manure for many years, is not,
relatively to other constituents of crops, deficient in potash. Had such
been the case, the sulphate of ammonia and superphosphate of
lime--manures which contain no potash--would not have give a an increase
of 84 bushels of potatoes per acre. There was sufficient potash in the
soil, in an available condition, for 179 bushels of potatoes per acre;
and the reason why the soil without manure produced only 95 bushels per
acre, was owing to a deficiency of ammonia and phosphates.
Since these experiments were made, Dr. Vœlcker and others have made
similar ones in England. The results on the whole all point in one
direction. They show that the manures most valuable for potatoes are
those rich in nitrogen and phosphoric acid, and that occasionally potash
is also a useful addition.
“There is one thing I should like to know,” said the Doctor. “Admitting
that nitrogen and phosphoric acid and potash are the most important
elements of plant-food, how many bushels of potatoes should we be likely
to get from a judicious application of these manures?”
“There is no way,” said I, “of getting at this with any degree of
certainty. The numerous experiments that have been made in England seem
to show that a given quantity of manure will produce a larger _increase_
on poor land than on land in better condition.”
In England potatoes are rarely if ever planted without manure, and the
land selected for this crop, even without manure, would usually be in
better condition than the average potato land of this section, and
consequently a given amount of manure, applied to potatoes here, would
be likely to do more good, up to a certain point, than the same amount
would in England.
Let us look at some of the experiments that have been made in England:--
In the Transactions of the Highland and Agricultural Society of Scotland
for 1873 is a prize essay on “Experiments upon Potatoes, with Potash
Salts, on Light Land,” by Charles D. Hunter, F.C.S., made on the farm of
William Lawson, in Cumberland. Mr. Hunter “was charged with the manuring
of the farm and the purchasing of chemical manures to the annual value
of £2,000,” or say $10,000.
“Potatoes,” says Mr. Hunter, “were largely grown on the farm, and in the
absence of a sufficiency of farm-yard manure, potash naturally suggested
itself as a necessary constituent of a chemical potato-manure. The soil
was light and gravelly, with an open subsoil, and the rainfall from 29
to 38 inches a year.”
The first series of experiments was made in 1867. The following are some
of the results:--
Bushels per acre.
No manure 221
4 cwt. mineral superphosphate 225
4 cwt. mineral superphosphate and } 240
4 cwt. of muriate of potash }
15½ tons farm-yard manure 293
“That does not say much for potash and superphosphate,” said the Deacon.
“The superphosphate only produced four bushels more than the no manure,
and the potash and superphosphate only fifteen bushels more than the
superphosphate alone.”
It may be worth while mentioning that one of the experimental plots this
year was on a head-land, “where the cattle frequently stand for
shelter.” This plot was dressed with only eight and a half tons of
manure, and the crop was over 427 bushels per acre, while a plot
alongside, without manure, produced only 163 bushels per acre.
“That shows the importance,” said the Deacon, “of planting potatoes on
rich land, rather than to plant on poor land and try to make it rich by
applying manure directly to the crop.”
The following are some of the results in 1868:
Bushels per acre.
1. No manure 232
{4 cwt. superphosphate }
2. {2 ” muriate of potash } 340
{2 ” sulphate of ammonia }
3. 20 tons farm-yard manure 342
4. {4 cwt. superphosphate } 274
{4 ” muriate of potash }
“Here again,” said the Doctor, “superphosphate and potash alone give an
increase of only forty-two bushels per acre, while on plot 2, where two
hundred weight of muriate of potash is substituted by two hundred weight
of sulphate of ammonia, the increase is 108 bushels per acre. It
certainly looks as though a manure for potatoes, so far as yield is
concerned, should be rich in available nitrogen.”
The following are some of the results in 1869:
Bushels per acre.
1. No manure 176
2. {4 cwt. superphosphate }
{¾ ” sulphate of magnesia } 306
{2 ” muriate of potash }
{2 ” sulphate of ammonia }
3. 4 cwt. superphosphate 189
4. {4 cwt. superphosphate } 201
{2 ” sulphate of ammonia }
5. {4 cwt. superphosphate }
{2 ” muriate of potash } 340
{2 ” sulphate of ammonia. }
6. {4 cwt. superphosphate } 249
{2 ” muriate of potash }
“This is a very interesting experiment,” said the Doctor.
“Superphosphate alone gives an increase of thirteen bushels.
Superphosphate and potash an increase of seventy-three bushels. The
potash, therefore, gives an increase of sixty bushels. Superphosphate
_and_ ammonia give twelve bushels more than superphosphate alone, and
the reason it does not produce a better crop is owing to a deficiency of
potash. When this is supplied the ammonia gives an increase (plots 5 and
6) of ninety-one bushels per acre.”
In 1870 the above experiments were repeated on the same land, with the
same general results.
In 1871 some experiments were made on a sharp, gravelly soil, which had
been over-cropped, and was in poor condition. The following are the
results:--
Bushels per acre.
1. {9 cwt. superphosphate } 186
{3 ” sulphate of ammonia }
2. {9 cwt. superphosphate }
{3½ ” muriate of potash } 204
{3 ” sulphate of ammonia }
3. No manure 70
4. {9 cwt. superphosphate }
{3½ ” muriate of potash } 205
{3 ” sulphate of ammonia }
5. 20 tons farm-yard manure 197
“On this poor soil,” said the Doctor, “the ammonia and superphosphate
gave an increase of 116 bushels per acre; and 3½ hundred weight of
muriate of potash an increase, on one plot, of eighteen bushels, and on
the other nineteen bushels per acre.”
In the same year, 1871, another set of experiments was made on a better
and more loamy soil, which had been in grass for several years. In 1869
it was sown for hay, and in 1870 was broken up and sown to oats, and the
next spring planted with potatoes. The following are some of the
results:
Bushels per acre.
{6¼ cwt. superphosphate }
1. {2½ ” muriate of potash } 321
{2½ ” sulphate of ammonia }
2. {6¼ cwt. superphosphate } 296
{2½ ” sulphate of ammonia }
3. No manure 252
4. {6¼ cwt. superphosphate } 311
{2½ ” muriate of potash }
5. 2½ cwt. sulphate of ammonia 238
6. 15 tons farm-yard manure 365
“It is curious,” said the Doctor, “that the plot with sulphate of
ammonia alone should produce less than the no-manure plot.”
“The sulphate of ammonia,” said I, “may have injured the seed, or it may
have produced too luxuriant a growth of vine.”
Another series of experiments was made on another portion of the same
field in 1871. The “no-manure” plot produced 337 bushels per acre.
Manures of various kinds were used, but the largest yield, 351 bushels
per acre, was from superphosphate and sulphate of ammonia; fourteen tons
barn-yard manure produce 340 bushels per acre; and Mr. Hunter remarks:
“It is evident that, when the produce of the unmanured soil reaches nine
tons [336 bushels] per acre, there is but little scope for manure of any
kind.”
“I do not see,” said the Doctor, “that you have answered my question,
but I suppose that, with potatoes at fifty cents a bushel, and wheat at
$1.50 per bushel, artificial manures can be more profitably used on
potatoes than on wheat, and the same is probably true of oats, barley,
corn, etc.”
I have long been of the opinion that artificial manures can be applied
to potatoes with more profit than to any other ordinary farm-crop, for
the simple reason that, in this country, potatoes, on the average,
command relatively high prices.
For instance, if average land, without manure, will produce fifteen
bushels of wheat per acre and 100 bushels of potatoes, and a given
quantity of manure costing, say $25, will double the crop, we have, in
the one case, _an increase_ of:--
15 bushels of wheat at $1.50 $22.50
15 cwt. of straw 3.50
------
$26.00
Cost of manure 25.00
------
Profit from using manure $1.00
And in the other:--
100 bushels of potatoes at 50 cents $50.00
Cost of manure 25.00
------
Profit from using manure $25.00
The only question is, whether the same quantity of the right kind of
manure is as likely to double the potato crop as to double the wheat
crop, when both are raised on average land.
“It is not an easy matter,” said the Deacon, “to double the yield of
potatoes.”
“Neither is it,” said I, “to double the yield of wheat, but both can be
done, provided you start low enough. If your land is clean, and well
worked, and dry, and only produces ten bushels of wheat per acre, there
is no difficulty in making it produce twenty bushels; and so of
potatoes. If the land be dry and well cultivated, and, barring the bugs,
produces without manure 75 bushels per acre, there ought to be no
difficulty in making it produce 150 bushels.
“But if your land produces, without manure, 150 bushels, it is not
always easy to make it produce 300 bushels. Fortunately, or
unfortunately, our land is, in most cases, poor enough to start with,
and we ought to be able to use manure on potatoes to great advantage.”
“But will not the manure,” asked the Deacon, “injure the quality of the
potatoes?”
I think not. So far as my experiments and experience go, the judicious
use of good manure, on dry land, favors the perfect maturity of the
tubers and the formation of starch. I never manured potatoes so highly
as I did last year (1877), and never had potatoes of such high quality.
They cook white, dry, and mealy. We made furrows two and a half feet
apart, and spread rich, well-rotted manure in the furrows, and planted
the potatoes on top of the manure, and covered them with a plow. In our
climate, I am inclined to think, it would be better to apply the manure
to the land for potatoes the autumn previous. If sod land, spread the
manure on the surface, and let it lie exposed all winter. If stubble
land, plow it in the fall, and then spread the manure in the fall or
winter, and plow it under in the spring.