February  28,  1901. 
JOURNAL  OF  HORTICULTURF  AND  COTTAGE  GARDENER. 
171 
County  Councils  in  particular,  starting  where  he  left  off — and  obtaining 
some  very  valuable  results,  not  less  in  fruit  growing  than  in  farming. 
In  dealing  with  this  large  subject  of  the  manuring  of  fruit  trees 
I  must  assume  that  my  readers  know  something  of  the  nature  and 
origin  of  soil,  as  well  as  its  constituents  ;  but  I  shall  endeavour  to  so 
explain  myself  that  even  those  most  ignorant  of  the  subject  hitherto 
may  be  able  to  follow  me  in  all  my  points — which  I  must  ask  the 
more  intelligent  and  better  informed  to  accept  as  an  apology  for  some 
elementary  explanations. 
There  are  certain  elements  of  plant  food  which  trees  must  have, 
and  without  which  they  will  do  no  good,  or  even  live  if  the  soil  is 
absolutely  destitute  of  them — happily  a  very  rare  condition.  There 
are  other  elements  which  the  trees  absorb  if  within  reach,  but  which 
do  not  appear  to  be  essential.  I  shall  only  deal  with  the  former  class, 
which  comprises  nitrogen,  phosphorus,  potash,  lime,  magnesia,  iron, 
and  sulphur.  As  the  last  two  are  usually  present  in  sufficient 
quantity  we  may  leave  them  out  of  consideration,  and  as  it  is  so 
seldom  necessary  to  supply  magnesia  we  will  leave  that  out  of 
consideration  also,  and  restrict  our  attention  to  nitrogen,  phosphorus, 
potash,  and  lime.  This  article  will  be  confined  to  the  nitrogenous 
manuring  of  fruit  trees. 
The  most  general  form  of  applying  nitrogen  is  in  that  of  dung.  Some 
may  be  surprised 
to  hear  that  ordi¬ 
nary  farmyard 
manure,  well 
rotted,  does  not 
contain  more  than 
1  per  cent,  of  plant 
food,  there  being 
about  10  lbs.  of 
nitrogen,  the  same 
amount  of  potash, 
and  only  about 
5  lbs.  of  phosphates 
in  a  ton.  Stable 
manure  is  a  little 
richer  than  ordi¬ 
nary  farmyard 
manure  (unless 
the  latter  is  from 
a  covered  yard), 
poultry  manure 
about  twice  as 
rich,  and  pigeon 
manure  fully  eight 
times  as  rich,  a 
ton  of  this  con¬ 
taining  about 
70  lbs.  of  nitrogen. 
The  problem  of 
the  most  econo¬ 
mical  keeping  and 
using  of  these 
manures  is  a  com¬ 
plicated  one,  and 
will  not  be  entered 
upon  here,  except  so  far  as  to  say  that  in  using  them  for  manurial 
purposes  alone,  as  distinct  from  mulching  to  retain  moisture,  they 
should  always  be  covered  in,  to  lessen  loss  of  ammonia  to  the  air,  even 
if  it  is  by  simply  covering  them  over  with  a  sprinkling  of  earth. 
Some  guanos  are  very  rich  in  ammonia,  and  it  is  ot  the  utmost 
importance,  if  economy  is  an  object,  that  they  should  be  dug  in, 
however  lightly.  Other  organic  manures  are  rape  dost,  containing 
about  5  per  cent,  of  nitrogen,  meat  refuse,  horns  and  hoofs,  shoddy 
and  greaves,  and  other  like  substances. 
The  digging  in  of  green  garden  refuse  is  also  a  useful  form  of 
nitrogenous  manuring.  It  is  a  pity  to  put  this  in  the  ashpit  if  it  can 
be  helped,  and  also  a  pity  to  burn  it,  as  in  that  case  the  nitrogen  is 
lost.  If  the  refuse  consists  of  weeds  the  earth  clinging  to  the  roots  is 
rich  in  nitrogen.  Vetches  may  very  profitably  be  grown  in  the  late 
summer  when,;  the  ground  would  otherwise  be  bare,  and  dug  in  in 
November.  They  enrich  the  supply  of  nitrogen  in  the  soil,  being  able, 
in  common  with  other  leguminous  plants,  to  get  nitrogen  direct  from 
the  air  through  the  instrumentality  of  the  nitrogen-producing  germs 
which  live  in  colonies  in  the  little  nodules  on  the  roots. 
Coming  to  artificial  nitrogenous  manures,  the  most  generally 
known  and  used  are  nitrate  of  soda,  containing  about  15  per  cent,  of 
nitrogen,  and  sulphate  of  ammonia,  containing  about  20  per  cent,  of 
nitrogen.  The  effect  of  these  two  manures  is  practically  the  same, 
though  different  in  their  method  of  action.  The  nitrate  of  soda  is 
very  Boluble,  and  being  very  easily  washed  out  of  the  soil  should,  for 
economical  use,  be  applied  in  small  quantities  several  times  duriug 
the  [season.  It  is  ready  formed  plant  food,  whilst  the  ammonia  of 
sulphate  of  ammonia  has  to  be  gradually  converted  into  nitrate  by 
the  nitrifying  germs  in  the  soil,  which  can  only  be  done  in  the  presence 
of  chalk.  Hence,  on  soils  lacking  in  lime,  sulphate  of  ammonia  is  not 
;  so  effective  as  nitrate  of  soda.  Not  being  so  liable  to  be  washed  out 
!  as  nitrate  of  soda  it  can  be  applied  in  une  dressing  in  the  spring, 
i  Given  suitable  soil  the  sulphate  is  more  economical  than  the  nitrate, 
when  the  price  of  the  former  does  not  exceed  the  price  of  the  latter. 
Having  very  briefly  described  the  forms  in  which  nitrogen  is  used 
and  their  action  on  the  soil,  we  come  to  consider  their  application  and 
effect  as  regards  fruit  trees.  At  the  outset,  let  it  be  stated  positively 
that  newly  planted  trees  should  never  be  treated  with  nitrogenous 
manures,  either  as  dung  put  in  the  hole  when  planted,  or  as  liquid 
manure.  The  effect  of  nitrogen  is  to  promote  growth  of  leaf  and 
stem,  making  the  leaves  dark  and  vigorous.  Trees  are  sometimes 
ruined  in  their  earlier  stages,  as  fruit-bearing  trees  by  the  application 
of  too  much  nitrogen,  as,  when  not  accompaaied  by  a  plentiful  supply 
of  phosphates,  it  induces  long-jointed,  sappy  wood,  which  does  not 
ri  pen  well,  and  rarely  produces  fruit.  When  the  tree  is  planted,  the  hole 
is  generally  filled  with  good  dark  soil.  If  it  is  taken  up  in  a  few  years 
the  soil  will  have  become  light  in  colour.  Why  is  this  ?  And  what 
caused  the  darkness  of  the  soil  In  the  first  place? 
The  humus,  or  orgmic  matter  in  the  soil,  which  contains  the 
nitrogen,  caused 
the  dark  colour. 
The  tree  has  fed 
on  this  and  used  it 
up.  There  is  no 
doubt  that  trees 
pretty  generally 
receive  too  much 
nitrogen  in  their 
earlier  stages,  and 
too  little  in  after 
years  when  they 
are  getting  ex- 
hausted  by  bear¬ 
ing.  It  is  not  for 
the  good  of  the 
tree,  from  a  bear¬ 
ing  point  of  view, 
that  it  should 
make  much  wood 
until  its  roots  have 
got  well  estab¬ 
lished  over  a  good 
sized  feeding  area. 
It  is  better  to  wait 
another  year  or  so 
for  the  wall  to  be 
covered  or  the 
space  to  be  nicely 
filled.  Ic  by  no 
means  follows  that 
because  the  soil 
round  the  tree  re¬ 
ferred  to  above  was 
light,  the  tree 
needed  nitrogen.  It  may  have  put  out  its  roots  so  that  it  was  getting 
plenty  2  or  3  yards  away. 
The  needs  of  a  tree  must  be  carefully  considered  as  a  case  by  itself. 
The  most  usual  index  to  its  requirements  in  the  way  of  nitrogen  is  in 
the  amount  and  quality  of  the  young  wood  it  is  making.  If  it  is 
very  vigorous,  especially  if  it  is  long-jointed  and  sappy,  the  tree  does 
not  need  any  nitrogen.  If,  on  the  other  hand,  the  tree  is  growing  in 
a  weakly  manner,  nitrogen  will  be  of  great  benefit.  If,  too,  the  tree  is 
bearing  heavily,  nitrogen  will  assist  the  swelling  of  the  fruit,  and  there 
will  be  no  fear  of  inducing  too  rank  a  growth  with  such  a  drain  on 
its  resources.  As  a  general  rule,  it  may  be  stated  that  if  the  tree  is 
making  less  than  a  foot  to  a  foot  and  a  half  of  growth  in  a  season, 
according  to  the  character  of  the  tree,  it  needs  nitrogen,  and  if 
making  more  than  that  amount  it  does  not  need  it.  Another  general 
rule,  not  necessarily  conflicting  with  the  above,  is  that  very  old  trees 
will  generally  benefit  by  the  application  of  nitrogenous  manures, 
preferably  animal  manures.  Hank  growth  is  not  usually  compatible 
with  fruitfulness,  and  must  not  be  encouraged.  An  exception  to  this 
and  to  some  other  statements  above  must  be  made  in  favour  of  some 
fruits  which  bear  principally  on  the  young  wood,  such  as  Raspberries, 
Black  Currants,  and  Gooseberries,  all  of  which  respond  to  liberal 
nitrogenous  manuring,  especially  a  mulohing  of  animal  manure,  by 
abundant  crops,  the  difference  in  both  the  size  and  quantity  of 
Black  Currants  being  especially  noticeable.  This,  of  course,  is  not  to 
the  exclusion  of  phosphates.  Some  growers  favour  the  application  of 
nitrate  of  soda  just  before  the  trees  come  into  blossom  to  facilitate  the 
setting  of  the  fruit. — A.  Petts. 
Peak  Olivier  de  Serres. 
