218  Report  on  the  Field  and  Feeding  Experiments  at  Woburn. 
to  the  land  on  plots  8b  and  9b.  On  these  plots  very  heavy  crops 
of  wheat  were  grown  in  the  five  preceding  years,  considering 
the  light  character  of  the  experimental  field  and  the  succession, 
of  bad  seasons  ; and  abnormally  large  quantities  of  readily 
soluble  nitrogenous  saline  manures  were  applied  in  the  experi- 
ments, partly  with  a view  to  exhaust  the  land,  if  possible,  more 
rapidly  than  under  ordinary  conditions,  and  partly  for  the 
purpose  of  demonstrating  the  fact  that  excessive  doses  of  nitrate 
of  soda  or  salts  of  ammonia  cannot  be  applied  to  corn-crops 
without  incurring  a great  loss. 
Turning  in  the  next  place  to  the  results  which  were  obtained 
on  plots  10  and  11,  it  will  be  seen  that  on  both  plots  the  halves 
which  received  no  dung  for  the  wheat-crop  of  1882,  the  yield 
both  of  corn  and  straw  was  greater  than  on  the  continuously 
unmanured  plots,  or  on  the  plots  which  were  manured  with 
minerals  only.  Thus  plot  10a,  dunged  in  each  of  the  five 
previous  seasons  with  about  4 tons  of  good  farmyard-manure, 
but  not  dunged  for  the  wheat-crop  of  1882,  15-6  bushels  of 
dressed  corn,  and  19  cwts.  and  22  lbs.  of  straw  were  produced,  or 
about  3 bushels  more  dressed  corn  than  the  average  yield  of 
the  two  continuously  unmanured  plots  1 and  7 ; whilst  the 
application  of  about  4 tons  of  dung  per  acre  on  plot  10b  raised 
the  produce  of  dressed  wheat  only  I bushel  above  the  produce 
of  plot  10a,  but  gave  a large  increase  of  straw. 
On  plot  11a,  manured  at  the  rate  of  about  8 tons  of  farmyard- 
manure  in  the  five  preceding  seasons,  but  not  dunged  for  the 
wheat-crop  of  1882,  practically  the  same  quantity  of  dressed 
wheat  and  about  1 cwt.  more  straw  than  on  the  corresponding 
plot  10a  were  obtained  ; whilst  the  application  of  about  8 tons 
of  dung  on  plot  11b  for  the  crop  of  1882  raised  the  produce  of 
dressed  corn  to  21 ’6  bushels,  and  that  of  straw  to  30  cwts.  3 qrs. 
and  4 lbs.  In  comparison  with  the  average  yield  of  the  two 
continuously  unmanured  plots  1 and  7,  the  dung  on  plot  11b 
gave  an  increase  in  round  numbers  of  9 bushels  of  corn  and 
22^  cwts.  of  straw  per  acre. 
These  experiments  clearly  show  that  the  dung  applied  on 
plot  10a  and  plot  11a  in  previous  years  left  some,  but  not  a 
considerable,  manure  residue  in  the  land,  and  that  this  residue 
apparently  was  not  larger  on  the  plot  which  was  manured 
previously  to  1882  with  about  8 tons  of  dung  annually  than  on 
the  plot  which  received  only  half  the  quantity  of  the  same  dung. 
Future  experiments  on  the  dunged  plots,  it  is  expected,  will 
show  how  long  and  to  what  extent  the  manure  residue  will  be 
perceptible  on  plots  10a  and  11a,  which  will  not  be  dunged  in 
the  succeeding  seasons.  As  far  as  present  experience  goes, 
a smaller  amount  of  nitrogen,  in*  the  shape  of  nitrate  of  soda  or 
