VOL.. XXXVIII. No. 43. i 
WHOLE No. 1351. I 
NEW YORK, OCT, 18, 1879. 
PRICE FIVE CENTS. 
£2.00 PER YEAR, 
[Entered according to Act of Congress, in the year 1879, by the Rural Publishing Company, In the office of the Librarian of Congress at Washington. — Entered at the Post-Office at New York City, N. Y., as second-class mat ter.] 
Jiflh Crops. 
Potato Number. 
COMPOSITION, MANUBING AND FEEDING 
QUALITIES OF THE POTATO. 
PROFES80R G. C. CALDWELL. 
Composition of the Potato. 
The resnlts of seventy analyses of the tuber, 
by various chemists, embracing a great many 
varieties and modes of culture, are summed up 
iu the following table ; 
Minimum. 
Maximum. 
Average. 
Water. 
88.29 
82.88 
75.77 
Nitrogenous sub- 
stance. 
0.60 
3.60 
1.70 
Crude fat. 
0.06 
0.8 
0.16 
Nou-nitrogenous ex- 
tractive substancea 
(starch, sugar etc.) 
t2.05 
26.57 
20.56 
Fiber. 
0.27 
1.40 
0.75 
Ash. 
0.42 
1.46 
0.97 
As the result of fifty-three analyses of the 
ash of the tuber, we have the following 
: 
Minimum. 
Maximum. 
Average. 
Potash. 
43.97 
73.61 
60.37 
Soda. 
U.oo 
16.93 
2.62 
Lime. 
0.51 
6.23 
2.67 
Magnesia. 
1.32 
13.58 
4.69 
Ferric oxide. 
0.04 
7 -18 
1.18 
Phosphoric acid.. .. 
8.3!) 
27.14 
17.33 
Sulphuric acid. 
0.44 
14.89 
6.49 
Silica.... 
0.00 
8.11 
2.13 
Chlorine. 
0.80 
10.75 
3.11 
Six analyses of the tops give the following 
average results: Potash, 31.78; soda, 2.81; 
lime, 32.65; magnesia. 16.51; ferric oxide, 2.80. 
phosphoric acid, 7.89; sulphuric acid, 6.82; 
Bilica, 4.82; chlorine, 5 78. Potash and phos¬ 
phoric acid are therefore the predominating 
ingredients of the asli of the tuber, and soda 
aud silica are evidently quite uuesseutial since 
they may be entirely absent; soda may also be 
entirely wanting in the tops. 
From these figures it may be estimated that 
in a crop of 150 bushels weighing 9,000 pounds, 
aud 600 poundB of tops, we should remove, of 
the three most valuable ingredients of plant- 
food, the quantities per acre given in the fol¬ 
lowing table, oruittiug fractions. For the 
purpose of comparison, I shall give also the 
quantities of these three substances gathered 
by a crop of wheat, 25 bushels, aud straw, 
2,500 pounds; aud of Iudiau corn, 50 bushels, 
stover 4,500 pounds, aud cobs 600 pounds. 
Nitrogen. 
Phoa. Acid 
Potash. 
Potatoes: tubers. 
26 
15 
53 
tops. 
— 
4 
u 
— 
— - ■ 
. 
Total. 
26 
19 
64 
Wheat: grain. 
30 
13 
8 
straw. 
12 
6 
17 
. 
— 
■ 
Total. 
42 
19 
25 
Indian corn: grain.. 
48 
20 
12 
Btover. 
22 
23 
41 
cobB... 
2 
— 
4 
■ ■ . 
■ 
Total.. 
72 
Manuring. 
43 
67 
From these figures it appears that to produce 
tiie potato crop, potash is required iu larger 
proportion than either nitrogen or phosphoric 
acid, and Dial more is required for this crop 
than for either wheat or corn, notwithstand¬ 
ing that the latter Is such a gross feeder. 
When we come to consider the comparative 
exhaustion of the soil by the two crops, re¬ 
membering that of the coru crop only the grain 
with 12 pounds of potash, is liable to leave the 
farm, while of the potato crop the tubers, with 
58 pounds of potash from every aere, are usu¬ 
ally exported, the usefulness of potash manures 
in potato culture would appear to be very 
plainly indicated. To the quantity of nitrogen 
gathered by the potato crop, as given iu the 
table, something must be added for the tops, 
with reference to which we find no determina¬ 
tions of this element. Making due allowance 
for this, the best manure for the potato would 
seem to be a complete one; that is to say, one 
containing all three of these substances—ni¬ 
trogen, phosphoric acid aud potash, with a 
large proportion of the last. 
No long and careful series of experiments 
have been tried with various manures und the 
potato, such as we have by Lawes and Gilbert 
with the cereals; but the general tenor of the 
results of such scattered field experiments as 
have been tried, supports this conclusion :— 
potash salts added to other manures, have, in 
most cases, increased the crop to a profitable 
extent, and, iu some cases, very considerably. 
Of the two potash salts used for agricultural 
purposes in Germany, and brought over here, 
the sulphate aud the chloride, the former gave 
decidedly better results in Grouveu’s experi¬ 
ment extending over three years; but refined 
Peruvian guano—guano treated witU.sulphuric 
acid—gave the best yield, much better than 
was obtained with stable manure. Bret- 
b.‘- hueidler obtained excellent results on a good 
6oil with potash salts alone, applied broadcast 
just before furrowing out for planting and 
harrowing in. Voeicker. as the result of field 
experiments conducted under his direction by 
several farmers, concluded that,|for light land, 
400 pounds of superphosphate, 200 of potash 
salts aud 200 of sulphate of ammonia would be 
the most profitable manure, and that on heavy 
laud the ammonia salts might be omitted, and 
a small quantity of nitrate of soda used. Other 
experiments, in Germany, have obtaiued the 
best results with sheep manure to which about 
one-tenth of potash salts had been added] 
Lawes and Gilbert have given the results of 
experiments for two years, which show much 
better yields with 400 pounds of ammonlt salts 
(or 550 of nitrate of soda), 350 of superphos¬ 
phate, 300 of sulphate of potash, 100 of sul¬ 
phate of soda and 100 of sulphate of magnesia, 
than with 14 tons of stable manure. Iu the 
experiments conducted in New Euglaud under 
Atwater s direction, the most uniformly good 
results were obtained with a complete manure 
containing a liberal proportion of potash salts, 
150 pounds of nitrate of soda, 300 of dissolved 
bone-black and 200 of chloride of potassium, 
costing $15.38 per acre, and yielding, in all but 
one of the experiments, from 40 to 130 bushels 
increase. But in a small majority of the same 
series of experiments, profitable results were 
obtained with either potash salts alone, applied 
at a cost of $4.50 per acre, or with superphos¬ 
phate and Ditrate of soda costing $10.58 per 
acre; that is, the increased crop would, at any 
ordinary prices, more than pay for the manure. 
From a general review of all the resnlts, it 
appears that on ordinary soils only complete 
manures are the safest, and that manures con¬ 
taining nitrogen alone, and no phosphoric acid 
or potash, are the most unlikely to yield profit¬ 
able returns. The larger yield and the better 
quality of potatoes obtained by so many ex¬ 
perimenters with commercial fertilizers than 
with stable manure, wtU suggest to the pro¬ 
gressive farmer experiments on his own farm 
with these manures. Salt on potatoes, while 
it may occasionally somewhat increase the 
crop, impairs its quality by diminishing the 
proportion of starch. 
Feeding Quality. 
The first table given above shows how widely 
the potato may vary in composition, especially 
with reference to the albuminous substance, 
which is taken to represent the proportion of 
albuminoids. A share of this variation may 
be due to differences in variety, but it is caused 
also by different modes of culture. In one ex¬ 
periment illustrative of this, while iu the pota¬ 
toes from the manured plot the nutritive ratio 
was 1:9, in potatoes manured with stable ma¬ 
nure and nitrate of soda, it was 1:6.5, But, 
although generally the richer an article of fod¬ 
der is in nitrogenous substance, just in that pro¬ 
portion it is more valuable, this is not always 
necessarily so, for, as recent investigations 
have shown, this Bubstance is made up partly 
of compounds of nitrogen that cannot in any 
sense discharge the important functions in the 
animal economy that belong to the albumin¬ 
oids. In the potato but little more than half of 
the nitrogenous matter is albuminous. We do 
not yet know what variations there may be 
in the proportion of real albuminous matter, 
whether induced by different modes of cultiva¬ 
tion, or the result of difference in variety. 
The nutritive ratio of the potato, or the ratio 
of the albuminoids to the non-nitrogenous ex¬ 
tractive matters, plus 2} times the fat, is given 
iu the books at 1:10.6; this is based on the as¬ 
sumption that all the uitrogenous substance 
consists only of albuminoids ; this reduction in 
the proportion of allnuuiuoids to about 53 per 
cent, of the total uitrogenous substance, makes 
still greater the already wide nutritive ratio of 
the potato, and increases the necessity of sup¬ 
plementing it, when used for fodder, with other 
materials, like bran or oil-cake, rich in nitro¬ 
gen, it being desirable that this ratio should be 
1:5 to 7 in all ordinary feeding. 
POTATO CULTURE IN OHIO. 
W. I. CHAMBERLAIN. 
Certain counties or parts of counties in 
northern Ohio seem specially adapted in soil 
and climate to the culture of potatoes. Such 
are portions of Lake, Cuyahoga, Portage aud 
Summit counties. The “ potato regions” lie 
chiefly on, or near, the bank of the lake or of 
the Cuyahoga River where the soil is a sandy 
or gravelly loam, where local showers are 
SUPERIOR. 
RUBY. 
MANHATTAN. 
