204 
JOURNAL  OF  HORTICULTURE  AND  COTTAGE  GARDENER. 
September  15,  1898. 
NITROGEN  AND  FOOD  SUPPLY. 
Dr.  Walter  Maxwell,  Director  and  Chief  Chemist  of  the  Experi¬ 
ment  Station  and  Laboratories  of  Hawaii,  sends  some  observations  to 
the  “  Daily  News”  on  the  nitrogen  supply  as  dealt  with  by  Professor  Sir 
A  illiam  Crookes  in  his  Presidential  address  to  the  British  Association. 
In  the  course  of  these  he  says  : — There  was  a  period  when  nitrogen 
practically  did  not  exist  at  all  upon  the  surface  of  the  solid  parts  of  the 
earth,  and  we  have  no  grounds  for  considering  that  during  any  period  of 
the  earth’s  history  the  nitrogen  content  of  the  soil  and  surface  was  greater, 
nor  even  as  great,  as  it  is  to-day.  We  have  to  regard  the  atmosphero  as 
the  primary  source  of  the  present  solid  forms  of  nitrogen  existing  upon 
the  earth’s  surface.  Vegetable  organisms  are  the  agencies  by  which  the 
element  is  conveyed  from  the  air  to  the  earth,  and  plant  and  animal 
decay  is  a  means  by  v,  hich  the  element  is  returned  to  the  atmosphere. 
This  grand  circulation  of  the  element  has  proceeded  from  the  day  of  the 
dawn  of  vegetable  existence,  gathering  in  volume  with  the  augmentation 
of  living  and  dying  forms. 
As  to  our  knowleoge  of  the  means  or  modes  by  which  Nature  con¬ 
ducts  this  “circulation”  of  nitrogeD,  we  are  bound  to  consider  it  much 
less  precise  than  the  tenor  of  Professor  Crookes’  remarks  would  lead  the 
public  to  believe.  Since  it  was  discovered  that  plants  have  the  power  of 
taking  nitrogen  direct  from  the  air,  and  up  to  the  present  day  it  has  been 
believed  that  only  certain  plants  exercise  this  function.  This  limiting  of 
the  function  very  much  to  certain  organisms  (Leguminotss)  is  purely  the 
result  of  the  failure  of  our  present  technical  means  of  investigation  to 
observe  the  effects  of  natural  processes  unless  they  are  on  a  palpably 
visible  scale,  and  our  inability  to  detect  the  more  delicate  processes. 
Physiological-chemical  authorities  have  said  “the  legumes  take 
nitrogen  from  the  air  and  convey  it  to  the  soil ;  but  the  Grammas 
do  not  exercise  this  function.”  But  the  modes  and  proportions  by 
which  this  transfer  of  nitrogen  is  conveyed  from  the  air  to  the  soil 
by  the  great  mass  of  vegetation  are  too  delicate  to  be  measured  by  means 
at  present  in  our  use.  For  example,  130  lbs.  of  nitrate  of  soda,  which  is 
enough  to  cause  the  difference  between  a  good  and  a  bad  crop  of  Oats, 
and .  about  the  amount  commonly  added  to  a  crop,  contains  20  lbs. 
of  nitrogen.  When  this  amount  is  distributed  in  the  soil  over  an  acre  of 
ground  we  have  not  a  single  chemical  means  that  can  detect  the  addition, 
or  of  twenty  times  the  amount  of  this  addition  of  nitrogen  to  the  soil  ; 
yet  the  Oat  and  Wheat  crop  detect  the  addition.  The  writer  has 
repeatedly,  and  for  years,  noted  this  subtle  office  of  cereal  crops,  even 
where  the  ground  may  be  said  to  have  been  full  of  organic  nitrogen.  In 
tropical  soils  it  is  not  unusual  to  find  1  per  cent,  of  nitrogen  in  the 
surface  soil,  which  means  not  less  than  35,000  lbs.  of  nitrogen  per  acre  to 
a  depth  of  1  toot.  This  mass  of  nitrogen,  however,  is  present  in  such  an 
extremely  unavailable  state  that  the  artificial  addition  of  merely  20  lbs.  or 
50  lbs.  of  nitrogen,  in  an  available  state,  is  at  once  detected  and  used  by 
the  plant. 
Again,  concerning  the  forms  in  which  plants  take  up  nitrogen  that  is 
already  to  hand  in  the  soil,  our  knowledge  is  still  very  inexact.  Even 
to-day  authorities  maintain  that  plants  can  only  assimilate  nitrogen  as 
nitrates,  and  after  it  has  been  prepared  by  the  soil  bacteria  for  reception  ; 
further,  that  these  soil  bacteria  can  only  carry  on  their  work  of  “nitrifica¬ 
tion  ’  in  soils  free  from  acidity  or  sourness.  Well,  the  wriier  has 
analysed  Ferns  found  growing  in  the  most  acid  of  tropical  soils,  and  by 
the  sides  of  fumaroles,  near  by  active  volcanoes,  where  the  sulphur  from 
the  sulphur  acids  escaping  in  the  steam  was  deposited  on  the  leaves,  and 
yet  these  Ferns  were  very  rich  in  assimilated  nitrogen.  We  give  these 
examples  in  order  to  indicate  how  elementary  is  the  state  of  our  present 
knowledge  of  natural  processes,  and  we  quoted  the  nitrogen  contents  of 
soils  in  order  to  distinguish  between  available  and  at  present  unavailable 
nitrogen,  the  contents  in  the  latter  form  being  still  ample  to  assuage  any 
immediate  fears  in  the  presence  of  the  picture  of  coming  desolation  that 
oir  \\  illiam  Crookes  has  put  before  us. 
If  we  judge  Brof.  Crookes’  predictions  from  the  ground  of  the  present 
social  and  economic  situation,  a  most  comforting  sense  of  his  fallibility 
comes  upon  us.  Never  has  the  civilised  population  of  the  earth  been  so 
large  and  so  well  fed,  and  at  no  time  have  breadstuffs  been  so  ample  and 
cheap.  r 
Concerning  the  immediate  waste  of  nitrogen  that  is  happening  by  the 
discharge  of  sewerage  into  the  sea,  this  is  not  a  total  and  permanent  loss. 
Nitrogen,  as  well  as  lime  and  phosphoric  acid,  is  as  much  needed  by  the 
ammal  and  vegetable  growths  of  the  sea  as  by  cereals  grown  upon  the 
land,  and  all  these  elements  are  in  part  returned  to  the  land  in  the  forms 
ot  the  millions  of  tons  of  fish,  &c„  and  of  plant  growths  that  are  brought 
from  the  ocean  to  the  shores.  Moreover,  we  can  assure  Sir  William  that 
the  escape  nitrogen  to  the  sea  in  the  waste  discharges  from  cities  is  not 
a  tithe  of  the  weight  of  nitrogen  which  is  borne  direct  from  the  land  to 
the  sea  by  common  land  drainage.  These  phenomena  are  a  part  of  the 
grand  system  of  circulation  of  the  elements  which  compose  the  mass  of 
a  n.et  result  of  this  circulation  the  amount  of  nitrogen  in 
solid  forms  within  and  upon  the  earth’s  surface,  and  which  is  available 
or  can  be  made  available,  is  almost  certainly  greater  to-day  than  at  anv 
other  period  of  the  earth’s  history. 
I  therefore  do  not  take  the  view  of  Sir  Win.  Crookes,  that  the  economy 
i  \aU«  *8  a^ou*:  breaking  down,  and  “  that  starvation  must  be  averted 
by  the  laboratory,'  and  that  “  before  we  are  in  the  grip  of  actual  dearth 
the  chemist  must  step  in  to  avert  the  day  of  famine.”  One  part  of  the 
work  of  practical  agricultural  chemists  to-day  is  to  try  to  promo'e  the 
conditions  by  which  the  natural  transfer  of  nitrogen  by  plants  from  the 
air  is  accomplished,  and  to  render  available,  with  the  least  amount  of 
vaste,  the  vast  reserve  of  nitrogen  that  is  locked  up  in  the  soil  in  organic 
forms.  I  have  no  doubt  that  the  interesting  calculations  of  Sir  A  m. 
Crookes  will  find  a  place  amongst  numerous  others  of  a  similar  nature 
which  the  world  has  received  and  talked  of,  but  which  have  not  seriously 
disturbed  the  everyday  economy  of  Nature. 
PLANTING  SPRING  CABBAGE. 
Tins  is  one  of  the  most  important  of  the  vegetable  garden  crops,  , 
and  merits  the  best  attention  as  regards  soil,  situation,  and  proper 
care  in  planting.  If  seeds  were  sown  in  July  or  the  early  part  of 
August,  the  plants  will  he  sufficiently  large  and  strong  to  be  planted 
permanently  from  the  seed  beds  or  lifted  from  the  quarters  where 
the  seedlings  have  been  pricked  out  several  weeks  in  order  to 
strengthen. 
This  system  of  transplanting  the  seedlings  as  soon  as  they  are 
large  enough  for  the  purpose  is  adopted  by  many  good  growers, 
because  they  find  that  the  general  growth,  sturdiness,  and  fibrous  _ 
root  formation  is  encouraged  thereby.  Each  plant  when  pricked  out  has 
a  clear  space  in  which  it  can  develop,  its  leaves  receiving  an  equal 
share  of  light  and  air ;  consequently  the  whole  plant  has  an  upright, 
sturdy  character  which  fits  it  well  for  its  winter  endurance.  In  some 
parts  of  the  country  Cabbage  requires  both  to  be  sown  early  and 
planted  as  early  in  September  as  possible,  so  that  the  plants  may  get 
well  established  before  the  growth  in  autumn  practically  ceases.  It  is 
not  desirable  in  any  district  to  have  large  and  sappy  soft-leaved  plants, 
as  these  invariably  stand  the  poorest  chance  of  passing  through  the 
vicissitudes  of  winter  weather.  Small  but  sturdy  plants  are  far 
superior,  and  such,  planted  to  constitute  the  main  crop,  may  usually 
be  relied  upon  to  pass  through  ordinarily  severe  weather  without 
serious  injury. 
In  selecting  plants,  therefore,  it  is  best  to  place  the  most  forward 
in  rows  together.  If  very  early  hearts  are  required  these  plants  may 
be  expected  to  furnish  them  if  given  moderately  rich  soil  and  a  some¬ 
what  shelti  red  position. 
The  best  position  for  the  main  crop  is  undoubtedly  an  open  one  on 
firm,  fertile,  but  not  over-enriched  soil.  Here  they  will  grow  slowly 
but  hardily.  Cabbages  never  grow  well  on  poor  land,  but  the  plants 
placed  out  now  will  succeed  admirably  on  ground  that  has  been 
liberally  manured  for  a  previous  crop.  Heavily  manuring  now,  and 
then  planting  is  not  advisable  except  on  the  very  poorest  soil,  after 
which  it  should  be  made  firm,  so  that  a  steady,  sturdy  growth  may 
be  induced  rather  than  a  strong  one  in  rich  loose  soil. 
Having  prepared  the  ground  well,  either  by  forking  or  digging  so 
as  to  intermix  the  enriching  material  and  break  down  the  clods,  very 
light  soil  should  be  made  firm  by  treading  or  rolling,  only  doing,  this, 
however,  in  dry  weather.  The  firming  process  not  only  consolidates 
the  particles,  rendering  rapid  evaporation  of  moisture  less,  but  it  assists 
the  freer  formation  of  a  mass  of  fibrous  roots. 
Draw  drills  18  inches  to  2  feet  apart,  according  to  the  variety  of 
Cabbage  to  be  planted.  The  most  generally  useful  distance  the  rows 
should  be  apart  is  2  feet,  and  the  space  between  the  plants  18  inches. 
Some  growers  desirous  of  securing  early  cutting  of  small  hearts  place 
the  plants  a  foot  apart  in  the  rows.  This  affords  an  opportunity  to 
cut  out  every  other  plant  before  the  whole  grow  too  large  to  spoil 
one  another.  The  drills  may  be  3  inches  deep.  They  serve  to  hold 
water  for  the  benefit  of  the  plants  during  the  early  part  of  the  time 
after  planting,  and  they  also  afford  a  little  protection.  Subsequently 
the  soil  may  be  levelled  close  up  to  the  stems,  as  that  will  make  the 
plants  more  secure  in  the  ground,  they  being  liable  to  be  loosened  by 
strong  winds. 
The  best  plants  ought  in  all  cases  to  be  selected  for  planting. 
Those  drawn  direct  from  the  seed  beds  cannot  be  obtained  with  soil 
adhering  to  the  roots  if  the  seedlings  are  growing  thickly  together,  but 
it  the  seeds  were  sown  thinly  a  large  number  may  be  obtained  with 
good  balls  of  soil  if  lifted  carefully  in  a  moist  period.  It  is  not 
material,  however,  that  soil  should  adhere  to  the  roots,  as  with  care 
in  placing  the  roots  straight  down  in  good  soil  and  affording  a  little 
water  to  them  at  once  the  plants  will  quickly  be  established. 
The  seedlings  previously  transplanted  in  a  bed  to  strengthen 
should,  if  the  weather  be  dry,  have  a  good  watering  the  day  previous 
to  planting,  when  each  plant  may  be  carefully  lifted  with  all  its  roots 
preserved  among  plenty  of  soil  which  lifts  with  the  roots.  Smaller 
plants  may  be  left  in  the  beds  or  dibbled  in  4  inches  apart  to 
remain  for  the  winter  and  plant  out  in  spring.  After  a  severe 
winter  there  are  often  many  vacancies  requiring  filling  up,  and  these 
plants  are  useful. 
Should  slugs  prove  troublesome  in  moist  weather,  the  largest 
must  be  sought  for  and  destroyed.  As  a  preventive  against  their 
ravages  it  is  advisable  soon  after  planting  to  scatter  newly  slaked 
lime  or  soot  about  the  plants.  Small  plants  soon  suffer  seriously  from 
these  pests,  which  attack  the  soft  stems  and  riddle  the  leaves. 
Frequent  hoeing  in  dry  weather  may  be  practised.  It  is  an  aid  to 
growth  ;  a  disturber  of  slugs,  which  hide  in  the  soil  under  the  lower 
leaves  ?fct  warms  the  soil  by  admitting  air,  and  keeps  down  weeds. 
