Fixation  of  Free  Nitrogen. 
117 
The  general  scheme  is  to  grow  two  nitrogen  fixing  crops, 
followed  by  two  others  requiring  the  combined  nitrogen 
which  has  been  accumulated  by  the  previous  growth  of  clover 
and  beans.  There  is  thus  a clear  gain  of  nitrogen  to  the  farm 
over  and  above  what  is  being  sold  away  as  wheat  and  [)otatoes, 
meat  and  wool. 
The  rotation  began  with  beans,  sown  in  February,  red 
clover  being  sown  among  the  beans  in  April.  When  the 
beans  were  podded  and  the  corn  well  formed,  but  while  the 
j)lant  was  still  green  and  succulent,  the  whole,  clover  and 
beans  together,  was  cut  and  made  into  silage,  the  quality  of 
the  resulting  product  being  good,  because  the  stemmy  nature 
of  the  beans  kept  the  mass  o])en  and  induced  the  right  kind  of 
fermentation.  The  second  cut  of  clover  was  made  into  silage 
also,  and  in  the  second  year  the  clover  was  made  into  hay  or 
silage  in  the  usual  way.  The  clover  ley  was  deeply  broken  up 
by  steam,  a considerable  dressing  of  basic  slag  and  whatever 
dung  had  been  made  were  then  ])ut  on  for  the  root  crop, 
a dressing  of  slag  and  kainit  having  been  previously  used 
for  the  beans. 
The  rotation,  however,  did  not  prove  a success  in  practice  ; 
it  depended  upon  the  making  of  silage,  and  this  was  found  to 
result  in  too  great  a loss  of  dry  matter  to  be  an  economical 
way  of  utilising  a fodder  croj).  The  beans  and  clover  mixture 
were  weighed  as  they  went  into  the  silo  and  the  water  they 
contained  was  determined  by  drying  a portion  ; similar  estima- 
tions made  when  the  .silage  was  carted  out  of  the  stack  or  silo 
showed  a wastage  equal  to  nearly  half  of  the  original  dry 
matter.  Other  difticulties  arose  from  the  dry  .seasons  which 
prevailed  throughout  the  period  1890-1900.  It  was  found 
difficult  to  obtain  a satisfactory  growth  of  clover  in  many  of  the 
years,  and  again,  it  was  very  doubtful  if  red  clover  could  be 
maintained  on  that  soil  for  two  out  of  every  four  years. 
The  repeated  failures  with  red  clover  turned  Mr.  Mason’s 
attention  to  lucerne,  a crop  which  was  practically  unknown  on 
his  clay  soil,  but  which,  as  the  tank  experiments  showed,  could 
effect  an  enormous  fixation  of  nitrogen.  Writing  to  Sir  Henry 
Gilbert  in  1896,  Mr.  Mason  says  : “ 1 have  been  going  on 
with  my  agricultural  scheme  as  first  laid  out — with  modifica- 
tions. My  success  on  the  whole  has  not  been  striking,  but 
the  two  dry  seasons  have  had  something  to  do  with  it.  . . . 
I have  long  had  my  eye  on  lucerne  as  a plant  likely  to  help  me 
out  of  my  difficulty  and  widen  the  distance  between  the  clover 
