The  Woburn  Field  Experiments , 1910.  333 
It  will  be  observed  that  in  each  ease  the  limed  plots  (2,  4,  6) 
gave  a better  crop  than  the  corresponding  plots  (1,  3,  5)  to 
which  mineral  manures  but  no  lime  had  been  given  with  the 
green  crops.  This  difference  had  not  been  previously  noted, 
and  may  be  due  to  the  depletion  of  the  soil  in  lime.  As 
between  the  wheat  crops  grown  after  green-manuring  with 
tares,  rape,  and  mustard  respectively,  there  wrere  the  same 
general  differences  as  previously  noticed,  the  average  of  the 
two  “ tares  ” plots  being  14'7  bushels  per  acre,  that  of  the 
“ rape  ” plots  2TG  bushels,  and  of  the  “ mustard  ” plots  22‘3 
bushels.  The  corn,  as  a whole,  was  of  rather  poor  quality,  too 
yellow  in  colour,  and  lacking  in  “strength.” 
These  results,  confirmed,  as  they  have  been,  by  frequent 
repetition,  allow  of  no  doubt  as  to  their  significance,  and  clearly 
show  that,  on  a soil  such  as  that  of  Woburn,  mustard  is  a better 
crop  for- ploughing-in  green  than  are  tares.  It  is  now  proposed 
to  vary  the  experiment  by  growing  the  green  crops  as  before, 
but  feeding  them  on  the  land  by  sheep,  instead  of  turning 
them  in  green. 
Varieties  of  Lucerne  {Stackyard  Field),  1910. 
The  three  plots  of  Lucerne — Provence,  American,  and 
Canadian — first  sown  in  1905,  still  remained  on  the  ground, 
though  the  Argentine  varieties,  sown  in  1909,  had  failed. 
The  plots  were  cleaned  in  March,  1910,  and  during  the  season 
three  cuttings  of  each  lot  were  obtained,  viz.,  on  June  30, 
August  20,  and  November  8,  after  which  the  plots  were  all 
dug  up  in  preparation  for  a more  extended  experiment  with 
lucerne,  the  Provence  and  American  varieties  having,  to  all 
purpose,  come  to  an  end,  though  the  Canadian  variety  would 
have  continued  to  yield  a crop  for  some  years  more.  The 
weights  of  green  produce  are  given  in  Table  VIII. 
Table  VIII. — Varieties  of  Lucerne  {Stackyard  Field). 
Plot 
Green  produce  per  acre.  1910  (fifth  year). 
T. 
c. 
q. 
lb. 
A 
Provence  seed 
9 
8 
2 
0 
B 
American  seed  ..... 
9 
4 
1 
14 
C 
Canadian  seed  ..... 
16 
10 
0 
0 
It  will  be  thus  seen  that  in  1910,  as  for  every  one  of 
the  four  previous  years,  the  Canadian  variety  has  given  a 
markedly  higher  crop  than  the  other  two.  The  real  point 
of  interest  is,  however,  what  has  been  the  cause  of  this  ? 
Is  it  possible  that  the  seed,  grown  under  Canadian  con- 
ditions, has  become  more  hardy  and  better  suited  for  a 
