Report  on  the  Field  and  Feeding  Experiments  at  Woburn.  215 
produce  as  good  an  effect  as  salts  of  ammonia.  In  such 
seasons  nitrate  of  soda  appears  to  expend  its  fertilising  powers 
more  in  producing  straw  than  corn,  and  on  the  whole  to  be  a less 
beneficial  manure  for  wheat  than  salts  of  ammonia.  However, 
it  would  be  dangerous  to  express  too  confident  an  opinion  on 
the  relative  merits  of  nitrate  of  soda  and  sulphate  of  ammonia 
as  nitrogenous  manures  for  wheat. 
As  far  as  my  experience  goes,  I can  only  state  the  fact  that  in 
one  season  a spring  top-dressing  of  nitrate  of  soda  has  a better 
effect  upon  wheat  than  sulphate  of  ammonia,  and  in  another 
season  the  reverse  is  the  case,  showing  clearly  how  desirable  it 
is  to  persevere  with  systematic  field  experiments,  and  not  to  be 
content  with  a few  haphazard  experimental  field-trials,  which  in 
many  cases  do  more  harm  than  good,  if  the  results  obtained  are 
interpreted  by  an  incautious  and  inexperienced  experimenter. 
The  second  unmanured  plot  (No.  7),  with  one  exception,  due 
to  the  accidental  depredations  of  the  wire-worm,  in  the.  previous 
five  years  gave  a better  crop  than  the  first  unmanured  plot 
(No.  1),  and  these  two  plots  have  maintained  the  same  character 
in  the  sixth  season  of  continuous  growth  of  wheat,  when  the  pro- 
duce of  dressed  corn  on  plot  No.  7 was  about  1 bushel  more 
than  on  plot  No.  1. 
Purely  mineral  manures,  as  in  former  seasons,  had  but  a slight 
effect  on  the  last  season’s  wheat-crop  ; and  on  plot  4 they  gave 
only  about  2 bushels  more  dressed  corn  than  the  average  pro- 
duce of  the  two  plots  which  for  the  last  seven  years  had  not 
received  any  kind  of  manure. 
On  the  other  hand,  ammonia  alone  on  plot  2 gave  32  bushels 
of  dressed  wheat  per  acre,  that  is,  an  increase  of  about  250  per 
cent,  of  dressed  corn  over  the  average  produce  of  the  two  con- 
tinuously unmanured  plots  (plots  1 and  7),  amounting  to  12f 
bushels  per  acre. 
A less  favourable  but  still  very  marked  result  was  obtained 
on  plot  3,  top-dressed  in  spring  with  nitrate  of  soda,  and  other- 
wise left  unmanured  for  the  last  seven  years. 
The  best  wheat  was  grown  on  plot  5,  manured  in  autumn 
with  minerals,  and  top-dressed  in  spring  with  salts  of  ammonia. 
The  wheat  from  this  plot  weighed  59’6  lbs.  per  bushel,  and  the 
yield  per  acre  was  35  bushels  in  round  numbers.  The  propor- 
tion of  straw  to  corn  on  this,  as  on  all  the  other  plots  in  relation 
to  the  corn,  was  unusually  and  excessively  high  last  season, 
especially  on  the  nitrate-of-soda  plots,  as  already  pointed  out. 
I need  hardly  repeat  in  this  Report  that  the  experiments  on 
the  continuous  growth  of  wheat  and  barley  which  wTere  begun 
seven  years  ago  are  not  instituted  with  a view  of  giving 
practical  illustrations  of  profitably  growing  corn-crops  on  light 
