39*


INVESTIGATION   BY   CULTURE   EXPERIMENTS


Table  70.  The  land  was  known  to  have  been  used  for  meadow  and
pasture  for  at  least  two  centuries  previous  to  the  beginning  of  these
experiments.
The  field  was  known  as  The  Park,  and  consisted  of  normal,  nearly
level  upland  soil,  very  similar  to  Agdell,  Broadbalk,  Hoos,  and
other  Rothamsted  fields,  except  that  The  Park  had  not  been  heav-
ily chalked  in  the  earlier  years,  while  the  other  Rothamsted  fields
(with  the  exception  of  Geescroft  at  least)  had  received  chalk  dress-
ings probably  amounting  to  100  tons  or  more  of  calcium  carbonate
per  acre.
The  Rothamsted  Station  has  no  knowledge  of  any  grass  seed
ever  having  been  sown  on  The  Park,  either  before  or  since  the
beginning  of  the  experiments.  From  1856  to  1874  only  the  first
crops  were  harvested  and  weighed  as  hay,  the  second  crops  having
been  fed  off  by  sheep,  as  a  rule,  and  the  sheep  having  been  con-
fined upon  the  plots  so  that  the  droppings  were  returned  to  the
respective  plots.  Since  1874,  the  second  crops,  when  sufficient  in
amount  to  justify  it,  have  also  been  harvested  and  removed  as  hay.
On  a  few  plots  the  treatment  was  not  fully  decided  upon  until  a
few  years  after  the  beginning  of  the  experiments.  Thus,  plot  u
was  divided  in  1862,  when  the  addition  of  sodium  silicate  was
begun  on  11-2.  At  the  same  time  the  application  of  potassium  was
discontinued  on  plots  8  and  10  and  the  sodium  sulfate  changed  from
200  pounds  to  500  pounds  for  1862  and  1863  and  then  to  250
pounds.  The  periods  represented  in  the  first  column  of  averages
vary  from  7  to  10  years.
