442 
THE  TROPICAL  AGRICULTURIST. 
[Jan.  2,  1893. 
priate  that  I should  begin  this  Handbook  with 
analyses  which  represent  the  composition  of  Ceylon 
soils,  so  far  as  this  has  been  determined. 
Much  has  been  said  for  and  against  the  prac- 
tical utility  of  soil  analysis.  When  first  the 
principles  of  chemistry  were  brought  to  bear 
upon  the  cultivation  of  the  soil,  it  was  confi- 
dently expected  that  methods  of  agriculture 
would  assume  the  nature  of  an  exact  science. 
The  cultivator  had  but  to  get  his  soil  and  a 
crop,  such  as  he  meant  to  raise,  analysed,  and 
he  would  see  at  a glance  what  constituents  it 
was  necessary  for  him  to  add  to  the  soils  in  the 
shape  of  manure.  Cases,  however,  occurred  in 
which  soils  which  yielded  good  results  on  ana- 
lysis, were  nevertheless  found  to  be  much  less 
fertile  than  others  which  appeared  to  be  lacking 
in  a due  proportion  of  available  elements  of 
plant  food.  Such  instances  still  occur  of  failure 
on  the  part  of  the  agricultural  chemist  to  ac- 
count for  the  infertility  of  a soil  by  the  analysis 
of  a sample  thereof.  Thus  the  planters  of  Ceylon 
have  had  before  them  the  case  in  which  the 
late  Dr.  Voelcker  analysed  a sample  of  soil  taken 
from  a patch  of  land  on  which  coffee  trees  were 
dying  out ; but  was  unable  to  discover  any  pe- 
culiarity in  the  composition  of  the  soil  to  account 
for  the  failure.  The  three  most  important  ele- 
ments of  plant  food-nitrogen,  phosphoric  acid, 
and  potash— Avere  found  in  proportions  consider- 
ably above  the  average  for  Ceylon  coffee  soils, 
while  no  actively  injurious  substance  Avas 
discovered.  While  frankly  admitting,  then,  that 
present  methods  of  soil  analysis  may  fail,  in 
certain  cases,  to  detect  a deficiency  of  available 
plant  food,  the  solvents  used  in  the  laboratory 
beiug  different  from  those  at  Avork  in  the  soil, 
chemical  analysis  may  neverthless  be  generally 
trusted  to  detect  an  absolute  deficiency  of  plant 
food  in  the  soil,  to  discover  the  presence  of  in- 
jurious substances,  and  to  give  a general  indi- 
cation of  the  resources  of  the  soil.  The  utility 
of  soil  analysis  is  also  greatly  increased,  Avhen 
a number  of  carefully  selected  samples  of  soils 
knoAvn  to  be  fertile  for  any  particular  product 
have  been  analysed,  so  as  to  afford  a standard 
Avith  Avliich  to  compare  other  soils  on  Avhiclx  it 
is  intended  to  raise  the  same  kind  of  crop,  or 
Avhich  have  disappointed  the  hopes  of  the  culti- 
vator. Care  should,  of  course,  be  taken  that  the 
sample  selected  for  analysis  is  representative. 
The  folloAving  are  the  instructions  issued  by  the 
Royal  Agricultural  Society  for  the  collection  of 
samples  of  soil  for  analysis:— 
“ JtxciA'e  a Avooden  box  made  6 inches  long  and 
6 inches  Avide  and  from  9 to  12  inches  deep, 
according  to  the  depth  of  the  soil  and  subsoil  m 
the  field.  Mark  out  in  the  field  a space  of  about 
12  inches  square ; dig  round  in  a slanting  di- 
rection a trench  so  as  to  leave  undisturbed  a 
block  of  soil  with  its  subsoil  from  9 to  12  inches 
deep  ; trim  this  block  or  plan  of  the  field  so 
as  to  make  it  fit  into  the  Avooden  box  ; invert 
the  open  box  over  it,  press  down  firmly,  then 
pass  a spade  under  the  box  and  lift  it  up,  gently 
jurn  over  the  box  and  nail  on  the  lid.  The  soil 
win1  then  be  received  in  the  exact  position  in 
which  it  i*  found  in  the  field. 
“ In  the  case  of  very  light  sandy  and  porous 
soils  the  wooden  box  may  be  at  once  inverted 
over  the  soil  and  forced  down  by  pressure  and 
thonWhen°the  soil  is  evidently  i of  unequal  char 
tie  ter,  separate  samples  should  OC  taken  0.  tne 
different  qualities  and  examined  separately, , as 
an  indiscriminate  mixing  could  only  by  chance 
result  ill  yielding  an  average  composition  of  t^e 
ivhole  fie’d.-,!  1 
Professor  Church,  formerly  of  the  Royal  Agri- 
cultural College,  Cirencester,  recommends  the  fol- 
loAving  method  of  sampling:  — 
“Where  the  soil  of  a field  is  uniformly  and 
distinctly  marked  out  from  the  subsoil,  three  or 
four  parcels  of  earth  may  be  taken  from  different 
parts  of  an  acre.  The  surface  vegetation  and 
accidental  foreign  matter  are  first  cleared  from 
the  selected  spots  ; then  a trench  is  dug  doA\-n 
to  the  subsoil,  so  as  to  leave  a square  block  12 
or  18  inches  square  of  the  surface  soil  intact ; 
from  this,  Aertical  slices  are  cut  until  5 kilo- 
grams or  10  lb.  of  each  have  been  obtained.  This 
material  is  then  placed  on  a piece  of  sacking  in 
AvheelbarroAv.  The  same  operations  are  re- 
peated on  the  other  selected  spots,  and  from  the 
united  quantities  of  soil  thus  obtained,  after 
thorough  mixing  with  the  spade,  a final  sample 
of  about  4 or  5 kilograms  (8  to  10  lb.)  is  taken. 
This  should  be  transported  to  the  Laboratory  in 
a Avooden  box,  not  in  a closed  metallic  or  glass 
vessel.  A sample  of  the  subsoil  may  be  obtained 
from  the  spots  opened  in  the  above  operations, 
the  depth  to  Avhich  the  subsoil  is  excavated 
being  at  least  equal  to  that  of  the  soil. 
Wlren  the  surface  soil  shows  any  kind  of  in- 
equality to  exist  in  the  texture,  color,  or  other 
character  of  the  surface  soil,  it  Avill  be  necessary 
to  take  a number  of  representative  specimens  from 
places  Avhich  resemble  one  another  closely,  and 
to  mix  them  together.  Then  a second  series  of 
samples  is  secured  from  other  places  in  the  field, 
differing  from  those  first  selected  ; but  also  re- 
sembling one  another-  Of  course,  if  three  sorts 
of  soil  exist  alongside  of  one  another,  a third 
series  of  samples  Avill  be  required.” 
Much  has  already  been  done  by  the  Ceylon 
Planters’  Association  in  getting  unmanured  repre- 
sentative coffee,  noAv  mostly  tea,  soils  analysed 
by  Mr.  John  Hughes;  but  scarcely  anything  has 
been  done  for  the  paddy  soils  of  the  island,  by 
Avay  of  determining  the  composition  of  fertile  and 
infertile  soils. 
The  folloAving  is  an  analysis  of  infertile  paddy 
soil  from  the  Walagamvala  paddy  fields.  This 
Avas  a soil  on  Avhich  the  paddy  plant  greiv  well 
enough  to  a certain  stage  ; but  Avas  unable  to 
mature  its  seed.  The  air-dried  soil  yielded  the 
folloAving  results  :— 
Analysis  of  Infertile.  Paddy  Soil * 
Moisture 
* Organic  matter 
Soluble  in  standard 
Hydrochloric  acid 
Silica 
Iron  protoxide 
Iron  peroxide 
Alumina 
Lime 
Magnesia 
Potash 
Soda 
Phosphoric  acid 
Sulphuric  acid 
Chlorine 
Quartz  and  \ 
f Insoluble  silicates  J 
per  cent< 
2-500 
6-460 
‘590 
•836 
3-526 
5-640 
•126 
•115 
•077 
•028 
•034 
•056 
'012 
80-000 
100-000 
* Containing  nitrogen  ‘129 
t Containing  silica  72*000 
This  analysis  represents  the  composition  of  the 
soil  Avhich  passed  through  a sieve  having  10  meshes 
to  the  lineal  inch.  The  sieve  kept  frfWk  3T  per 
