338 
The  Woburn  Field  Experiments , 1910. 
November  25,  1909,  and  a useful  crop  came  up  which  showed 
very  little  difference  between  the  several  plots.  The  crop  was 
cut  on  August  19, 1910,  carted  September  1 and  2,  and  threshed 
on  October  26. 
The  results  are  given  in  Table  XII. 
Table  XII. — Experiment  on  Residual  Value  of  Nitrogenous 
Top-dressings  applied  to  Mangolds,  1909.  Crop  of  1910, 
Wheat. 
Road  Piece  Field — Produce  per  acre. 
Head  com 
Tail 
corn 
Value  of 
Plot 
Manures  per  acre  used  for 
mangolds,  1909 
Weight 
Bush. 
Weight 
per 
bushel 
Weight 
quarter 
on  basis 
of  32 s. 
1 
Sulphate  of  ammonia,  1 cwt. 
Lb. 
1,550 
25-3 
Lb. 
61-2 
Lb. 
90 
s.  d. 
31  0 
2 
Nitrate  of  soda1  . 
1.800 
29-2 
61-5 
87 
31 
6 
3 
Calcium  nitrate1  . 
2,180 
350 
622 
100 
31 
6 
4 
Calcium  cyanamide1 
2,072 
34-1 
60-8 
110 
31 
6 
5 
No  top-dressing 
1,990 
322 
61-7 
85 
31 
6 
i In  quantity  to  supply  as  much  nitrogen  as  that  contained  in  1 cwt.  sulphate  of 
ammonia. 
From  these  figures  it  will  be  seen  that  the  residue  left 
over  for  a second  crop  was  in  no  instance  of  material  value. 
Nitrate  of  soda  and  sulphate  of  ammonia,  as  was  expected, 
showed  no  residue,  but  rather  gave  a lowering  of  the  produce ; 
calcium  cyanamide  was  responsible  for  a surplus  of  2 bushels 
per  acre  of  corn,  and  calcium  nitrate  for  3 bushels  ; and, 
possibly,  this  was  connected  with  the  fact  of  their  both 
supplying  some  lime  to  the  land.  At  best,  however,  the 
influence  was  not  very  marked,  and  there  is  nothing  at  present 
to  lead  one  to  think  that,  in  regard  to  the  new  nitrogenous 
materials,  their  lasting  effect  requires  to  be  taken  into  serious 
consideration. 
Sugar-beet. 
As  mangolds  were  being  grown  in  Warren  Field  (see  page 
336)  it  was  thought  well  to  grow  experimentally  also  some 
sugar-beet.  Accordingly,  a plot  alongside  the  mangold  plots 
was  put  in  with  sugar-beet  under  just  the  same  conditions, 
manuring,  &c.,  as  the  ordinary  crop  of  mangolds.  The  seed 
used  was  white  Silesian  beet,  and  this  was  drilled  on  April  26, 
1910.  The  crop  was  pulled  on  November  2 and  weighed,  the 
comparative  weights  of  it  and  the  mangolds  being  : — 
Produce  of  roots  per  acre 
T.  c.  q.  lb. 
Mangolds  (“Yellow  Globe”).  . .31  11  3 14 
Sugar-beet  . . . . . 12  2 2 0 
