553 
June 27, 1903. 
THE GARDENING WORLD. 
Something about Plant Food. 
(Continued from page 486.) 
By J. J. Willis, Harpenden. 
Reverting to the subject, treated of in our last article, and 
assuming that the constituents—nitrogen, phosphoric acid, 
and potash—are the most important ingredients in a manure, 
and are those in which garden soils are the most likely to 
become deficient, we see from the table already given on the 
chemical composition of certain vegetables how the stores, 
of some of these plant foods within the soil would be affected 
by the removal of one ton of each of the crops enumerated. 
Constituents of Fruit . 
We now give the amount of the nitrogen, phosphoric acid, 
and potash extracted from the soil by the growth and removal 
of one ton of each of the following kinds of fruit in the fresh 
state as gathered for market. 
Amount of selected constituents in one ton of various fruits 
in fresli condition; quantities given in lbs. : — 
De cription of Fruit. 
Strawbcrrie 
Apples... 
Pears ... 
Gooseberries 
Cherries 
Figs ... 
Plums ... 
Apricots 
Grapes... 
Raspberries 
Nitroge . 
Phosphoric 
Acid. 
Potash. 
lb 
,b 
i r ‘- 
3'4 
2-4 
6'7 
2'9 
1-1 
4 2 
2*2 
0 9 
3-8 
1-3 
1-6 
3 4 
40 
To 
8-7 
2-2 
1-0 
146 
4 0 
0-5 
6’9 
4'2 
1-3 
6-4 
3'8 
3-1 
11-2 
3'4 
10-7 
7'8 
The importance of the element potash in the production of 
fruit is very plainly shown in the foregoing figuies, and more 
especially is this the case in the growth of bigs and Grapes ; in 
fact, the maturation and sweetness of the various kinds of 
fruit are particularly influenced by the amount of available 
potash in the soil. 
Looking at the above data without due consideration, one 
might be led to think that the amount of nitrogen, potash, 
and phosphoric acid is so very small in one ton weight of fruit 
that these substances might be neglected in, any manorial ap¬ 
plication that is given. But we have to remember that much 
more plant food is required to be present in the soil beyond 
what is actually taken up by the fruit itself. There are the 
leaves to be fed and nourished, in order that they may elabo¬ 
rate the nutritive juices for the production and ripening of the 
fruit, besides the maintenance of the structure of the trees 
themselves. Consequently the poorer the soil may be in 
what is termed its natural fertility or richness of plant food, 
the more complete must be the restoration of the ingredients 
carried away in the crops of leaves and fruit, if productive¬ 
ness is to bo maintained or increased. 
When land is in good heart, and planted with fruit trees, it 
may be some years before any considerable quantity of manure 
is required, because the range of roots is so very extensive that 
the feeding area is far larger than with ordinary garden crops. 
This seems to be the lesson taught by the Woburn Experi- 
mental Fruit Farm, so far as Apples, Pears, and Plums are 
concerned; but it is quite otherwise with Strawberries, Rasp¬ 
berries, and such-like quick-growing fruits, which must, be well 
fed if they are to be productive. 
Fruit Tree Requirements. 
Professor Yoorhees writes as follows : “ It is argued by many, 
and sometimes by those who should know better, that fruit¬ 
growing is quite similar to growing ordinary ornamental trees ; 
that the question of soil exhaustion is not a matter of veiy 
gieat importance, provided the soil is well cultivated; and 
that all soils contain sufficient quantities of the food elements 
to ensure. the relatively small available supply required by 
tile fruit from year to ye^tr.” 
It is admitted that on soils of good mechanical condition, 
well drained and well cultivated, which are naturally adapted 
for fruit as well as other garden crops, because well supplied 
with the essential constituents—nitrogen, phosphoric acid, 
potash, and lime—the exhaustion arising from the continuous 
removal of fruit crops will not become apparent for a long 
time; but it should be emphasised that it is only upon soils 
which possess these characteristics that the growth of fruit, 
even poor fruit, can be continued for any considerable period 
without the application of manures. 
It is, of course, true that the specific needs of kitchen vege¬ 
tables cannot be applied with any degree of accuracy to fruit 
crops, particularly the larger fruits, as Apples, Pears, Peaches, 
Apricots, Grapes, and Plums, because these differ from the 
vegetables, first in their habit, of growth ; second, in the charac- 
Camfanula balchiniana. #(See p. 555.) 
cer of the produce; and, third, m their relation to sou ex- 
nausuon. 
in Ule urst place, vegetables, as a rule, require but one year 
tor cue entire processes oi grow in ana maturation. nun 
crops, on cue oiner nanu, wim out lew exceptions, snow mat 
me purely vegetative processes continue ior tniee oi loui 
years, anu wim many nnus niucu longer; wluie alter me 
urst nearing penou uegins toe vegetative processes do not 
cease, but are coincident witn tne growtn ana ripening oi Uie 
iruit. 
in the second place, the product of fruit differs very 
materially in its character from that of ordinary iutciien 
vegetables, which mature their produce and die m one season, 
or are entirely removed from tne soil; whereas fruit requires 
a whole season for its growth and development—that is, it is 
necessary that there shall be a constant transfer of the nutri¬ 
tive juices from the tree to the fruit throughout the entire 
growing season; while the growth for each succeeding year 
of both tree, leaves, and fruit is dependent upon the nutrition, 
or, in other words, the plant food acquired and stored up in 
the buds and branches, as well as upon that which may be 
derived directly from the soil. 
In the third place, the relation of fruit-growing to soil ex¬ 
haustion is very different from that of kitchen vegetables, 
because in orchards or Vine borders, etc., there is an annual 
demand for specific kinds and proportions of soil constituents ; 
it is really a continuous cropping of the same kind; there is 
no opportunity, as in the case of ordinary garden crops, to 
correct the tendency to exhaustion by a frequent change of 
crops, or the growth of those which have a different root range, 
and require different kinds and amounts of plant food in¬ 
gredients. 
© 
(To be continued .) 
