752 
THE  TROPICAL  AGRICULTURIST 
[June  i,  1893. 
Elements  in  one  hectolitre  of  Sifted  Leaf-mould. 
Total  nitrogen 0'59  lb. 
Lime  . . , . . . . . . . 0'34  „ 
Phosphoric  acid  01 5 „ 
Potash  ..  ..  ..  ..  0'46  ,, 
Silica  sand..  ..  ..  ..  ..  108'68  „ 
Humus 12-39  ,, 
Assimilable  Elements : — 
Nitric  nitrogen  provided  in  6 months 
by  nitrification  . . , . . . 34‘45  grammes 
Phosphoric  acid  (soluble). . ..  2'60 
Potash  (soluble) 47'45 
Knowing,  therefore,  what  are  the  substances 
directly  assimilable  by  plants  in  one  hectolitre  of 
leaf -mould  ; it  is  important  to  enquire  the  best  means 
of  applying  to  the  soil  the  elements  that  are  wanting, 
or  are  not  present  in  sufficient  quantity. 
Nitrogen.—  Although  the  nitrification  in  the  leaf- 
mould  may  be  sufficiently  active  for  us  to  be  able  to 
dispense  with  nitrogenous  manures  in  most  cases, 
yet  there  are  certain  species  of  plants  which  rapidly 
develop  a large  mass  of  foliage,  and  these  cause  a 
rapid  and  extensive  draught  on  the  nitrogen.  For 
such,  it  will  always  be  advisable  to  use  nitrate  of 
soda  in  solution  when  watering,  and  to  supply  it 
frequently  and  in  small  quantities.  The  presence  of 
crystalline  nitrate  of  soda  in  direct  contact  with 
plant-roots  is  sometimes  hurtful,  and  the  plants  do 
not  get  the  full  benefit  of  the  supply. 
Nitrate  of  soda  should  be  given  in  doses  of  1 
gramme  per  litre  of  water,  that  is  about  a quarter 
ounce  for  two  gallons. 
To  calculate  the  quantity  to  be  applied,  we  rely 
on  the  fact  that  nitrate  of  soda  of  commerce 
contains  15  per  cent,  of  nitrogen.  For  cultivation 
removing  30  grammes  of  nitrogen,  there  must  be 
applied  200  grammes  of  nitrate  soda.  The  mould 
containing  so  much  humus,  absorbs  and  strongly 
l’etains  ammonia. 
It  might,  therefore,  be  thought  advisable  to  use 
ammonium  sulphate  as  a nitrogenous  manure.  But 
for  this  to  be  fixed  the  soil  must  contain  a certain 
proportion  of  lime.  This  will  take  the  acid  from 
the  sulphate  and  be  changed  into  ammonia  carbonate. 
For  this  salt  to  get  assimilated  by  plants,  it  must 
be  changed  into  nitric  nitrogen  by  nitrification. 
Phosphatic  Manures. — Assimilable  phosphoric  acid  is 
in  very  small  quantity  in  leaf-mould  ; it  is  therefore 
necessary  to  add  it  in  manure.  The  best  form  is 
that  of  pulverised  bone-phosphate.  Phosphate  of 
potash  is  also  excellent.  Superphosphates  yield  a 
certain  proportion  of  phosphoric  acid  soluble  in 
water,  but  in  leaf-mould  culture  they  are  not  to  be 
recommended,  being  almost  always  acid,  and  this 
introduction  of  sulphuric  acid  into  soils  poor  in  lime 
would  be  certainly  hurtful. 
We  recommend  precipitated  bone  phosphates  which 
may  contain  as  much  as  45°  per  cent,  of  soluble 
phosphoric  acid.  Basic  slag  is  also  strongly  recom- 
mended. This  product,  having  no  acidity  is  very 
good  for  soils  poor  in  lime;  it  must  be  used  finely 
ground,  and  mixed  with  the  earth.  The  quantity 
of  the  phosphates  to  be  applied  will  vary  according 
to  their  percentage  of  phosphoric  acid. 
If  we  have  need  of  more  rapid  assimilation,  phos- 
phates of  soda  and  potash  are  to  be  recommended. 
The  former  contains  one-half  its  weight  of  directly 
assimilable  phosphoric  acid.  It  may  be  dissolved  in 
water,  and  use  for  watering  the  soil  we  wish  to 
enrich. 
Phosphate  of  ammonia  is  sometimes  recommended. 
This  gives  excellent  results ; it  furnishes  both  phos- 
phoric acid  and  nitrogen,  but  it  is  too  costly  for 
general  purposes. 
To  sum  up,  we  shall  apply  bone  phosphates  or 
precipitated  phosphates  according  to  the  duration  of 
the  cultivation. 
For  plants  of  rapid  growth,  phosphates  of  potash, 
soda,  or  ammonia. 
Potash  Manures. — Leaf-mould  contains  a consider- 
able proportion  of  potash,  which  is  only|slowly  avail- 
able for  vegetation.  For  certain  cultivations,  es- 
pecially that  of  Ferns,  potash  manures  have  a very 
beneficial  effect.  The  most  rational  method  is  to 
use  carbonate  of  potash,  and  to  apply  it  dissolved 
in  water  on  to  the  soil  to  be  manured ; this  salt  is 
retained  by  the  soil,  and  the  plants  are  able  to  absorb 
it  as  they  need.  The  proportions  to  be  used  vary 
according  to  the  requirements  of  the  plants  culti- 
vated. Commercial  carbonate  of  potash  contains 
from  52  to  63  per  cent,  of  potash. 
Nitrate  of  potash  will  serve  both  as  a nitrogenous 
and  a pota,sh  manure  It  is  directly  assimilable  by 
plants  ; it  is  very  soluble  in  water,  and  must  be  used 
for  watering  in  the  same  proportions  as  nitrate  of 
soda.  It  is  an  excellent  manure,  containing  45  per 
cent,  of  potash  and  13  per  cent,  of  nitrogen.  It  is 
thus  valuable  when  we  wish  to  associate  nitrogen 
and  potash  together. 
A salt  likely  to  become  of  great  importance  to 
horticulture  is  sulpho-carbonate  of  potash,  which 
acts  as  a manure  and  as  an  insecticide.— J.  J.  Willis, 
Harpenden.— Gardeners'  Chronicle. 
TEA  CULTIVATION : 
PRACTICAL  EXPERIENCE. 
(By  a Tea  Planter.) 
TILTH — BURYING  PRUNINGS — CATTLE  MANURE. 
“ Tilth"  or  tillage. — My  experience  here  quite 
agrees  with  a correspondent  you  quoted  that  on  poor 
soil  tilth  without  manure  does  no  good,  in  fact  in 
my  case  I thought  it  did  harm  as  it  tended  to 
harden  the  wood  and  encourage  seeding.  They  had 
the  same  experience  on  the  adjoining  estate. 
At  the  same  time  I remember  digging  in  stable 
manure  factory  and  line  sweepings  on  a young 
field  in  the  lowcountry,  and  the  supply  running  short 
before  time  to  knock  off,  the  coolies  went  on  digging 
away  till  muster  time;  this  had  quite  a marked  effect, 
but  then  the  case  was  different,  this  was  young  land 
with  lots  of  roots  to  tare  up  and  cause  to  rot  more 
readily. 
Last  week  I saw  you  writing  strongly  on  burying 
primings.  Well  ; I have  done  a great  deal  at  that, 
considering  my  acreages.  It  is  beueficial  certainly , 
but  considering  cost  and  the  number  of  coolies  re- 
quired for  the  work,  especially  at  a busy  time  I 
question  if  it  has  any  advantage  (thats’  strong ! 
you’ll  say). 
But  let  us  reason  it  out.  Prunings  left  on  the 
ground  act  as  thatch  or  shade  and  prevent  the 
ground  from  being  washed  and  baked.  Ultimately 
a percentage  of  the  prunings  get  carried  away;  but 
it  is  principally  dry  twigs,  and  one  can  see  a layer 
of  mould  being  formed  from  the  prunings  which 
must  act  as  a barrier  between  the  atmosphere  and  soil. 
In  the  lowcountry  prunings  disappear  from  white- 
ants  after  a few  months,  but  there  no  one  can  doubt 
the  beneficial  effect  they  have  in  protecting  the  soil 
from  being  baked  by  the  fierce  rays  of  the  sun,  and 
also  shading  young  rootlets  near  the  surface  as  well 
as  collecting  and  retaining  dew  at  night. 
Were  it  not  that  thi  expense  is  prohibitive  there 
is  nothing  exoept  cattle  manure  that  has  so  marked 
or  so  lasting  effects  as  thatching  with  mana  grass 
where  procurable.  I am  not  writing  about  what  I 
have  not  tried  and  more  than  experimented  with. 
I agree  with  I think  all  you  have  written  in  fa- 
vour of,  but  I certainly  differ  about  burying  prunings. 
Thb  Drayton  (Ceylon)  Estate  Co — A Company 
has  been  forme!  umler  the  above  title  to  take  over  the 
Drayton  and  Yuill  field  estates.  The  oapital  is  to  be 
R750,000  in  7.500  snares  of  R100  ; but  the  shares  are 
all  privately  held,  chiefly  by  the  proprietors  of  the 
two  estates  mentioned.  In  future  they  will  be  worked 
together  as  one  estate.  The  tw  > contain  1,120  acres,  of 
which  920  acres  are  now  planted  in  tea.  The  vendors 
take  the  who  e of  the  purchase  money  (R671,000)  in 
fully  paid  up  shares  in  the  company,  and  tho  estates 
are  taken  over  as  from  1st  of  July  next. 
