336 
The  Woburn  Field  Experiments , 1910. 
Table  X. — Experiment  with  Nitrogenous  Top-dressings 
on  Oats,  1910. 
Butt  Close — Produce  per  acre. 
Head  corn 
Tail 
corn 
Value  of 
corn  per 
quarter 
on  basis 
of  19s. 
Plot 
Manures  per  acre 
Weight 
Bush. 
Weight 
per 
bushel 
Weight 
1 
Calcium  cyanamide1 
Lb. 
1,913 
52-1 
Lb. 
368 
Lb. 
233 
8.  d. 
18  0 
2 
Calcium  nitrate1  . 
1,812 
49-3 
368 
245 
18  6 
3 
No  top-dressing 
1,572 
42-9 
36*6 
1 65 
19  0 
4 
Nitrate  of  soda' 
1,779 
51-2 
34'7 
199 
18  0 
5 
Sulphate  of  ammonia,  1 cwt. 
1,771 
48-7 
36-4 
225 
18  6 
i In  quantity  to  supply  as  much  nitrogen  as  that  contained  in  1 cwt.  sulphate  of 
ammonia. 
the  best  being  the  untreated,  and  the  next  best  the  nitrate  of 
lime  and  sulphate  of  ammonia  lots. 
It  would  appear  from  this  experiment  that  the  conclusions 
of  1909  are  confirmed  by  the  present  series,  and  that  when  the 
same  money  value — or,  as  it  is  better  stated,  the  same  amount  of 
nitrogen — is  applied,  it  does  not,  in  the  case  of  corn  crops, 
matter  much  in  which  form  of  these  nitrogenous  top-dressings 
it  is  given. 
( b ) Experiment  on  Mangolds. 
In  1910,  a repetition  of  the  mangold  experiments  of  1909  was 
carried  out  on  Warren  Field,  the  variety  grown  being  “ Yellow 
Globe.”  The  previous  crop  was  wheat.  London  dung,  at  the 
rate  of  12  tons  per  acre,  was  spread  in  April,  1910,  and  along 
with  it  was  given,  to  all  the  plots  alike,  a dressing  of  3 cwt.  per 
acre  of  mineral  superphosphate,  1 cwt.  per  acre  of  sulphate  of 
potash,  and  2 cwt.  per  acre  of  common  salt.  The  mangold  seed 
was  drilled  on  April  26-28.  After  hoeing  and  singling,  the 
nitrogenous  top-dressings  were  applied  on  July  19,  the  same 
amount  of  nitrogen  being,  as  in  the  experiment  on  oats  just 
recorded,  given  to  each  plot.  The  crop  grew  well,  and  was 
pulled  November  2-11  and  the  roots  weighed. 
The  results  are  given  in  Table  XI.,  page  337. 
The  only  crop  that  fell  in  produce  below  that  of  the 
“ standard  dressing  ” was  the  sulphate  of  ammonia  one,  and  it 
is  worthy  of  note  that  this  same  occurred  in  the  experiments 
of  1909.  All  the  other  top-dressings  showed  an  increase,  this 
varying  from  about  1^  tons  per  acre  with  soot  to  tons  per 
acre  with  calcium  nitrate.  Calcium  cyanamide  produced  1 ton 
more  of  roots  than  did  nitrate  of  soda,  but,  in  turn,  1 ton  less 
