346 
Nitrogen  as  Nitric  Acid,  in  the  Soils 
land  was  again  ploughed  and  harrowed  on  October  27-29,  and 
wheat  drilled  on  all  the  plots. 
Before  calling  attention  to  the  quantity  of  nitrates  found  in 
the  soils  of  the  different  plots  at  the  time  of  sampling,  it  will  be 
well  to  consider  the  evidence  afforded  by  the  composition  of  the 
drainage-waters  collected  during  the  same  season.  The  drains 
in  Broadbalk  Field  are  from  2 feet  to  2 feet  6 inches  below  the 
level  of  the  land  ; whilst  the  nitrates  have  been  determined  in 
the  soil  to  approximately  the  same  depth,  namely,  27  inches. 
The  composition  of  the  drainage-waters  will  be  found  in 
Table  V.  The  thick  black  line  shows  the  interval,  October 
10-18,  in  which  the  samples  of  soil  were  taken. 
Table  V. — The  Nitrogen  as  Nitrates,  in  the  Drain age-Watebs  of  the 
Plots  in  Broadbalk  Wheat-Field,  from  March  1881  to  January  1882. 
March 
5,  6.  7, 
Mixed. 
August  30. 
Dec. 
Plot. 
A.M. 
6 30. 
P.M. 
2-3. 
Sept.  25. 
Oct.  14. 
Oct.  23. 
Nov.  25. 
Nov.  27. 
Dec.  7. 
17,  18, 
20,  21, 
Mixed. 
Jan. 
* Farmyard-mauure  applied  Oct.  27.  f Ammonium-salts  applied  Oct.  27. 
X Rape-cake  applied  Oct.  28. 
The  last  running  of  the  drains  preceding  the  harvest  of  1881 
occurred  on  March  7.  The  top-dressings  of  ammonium-salts, 
and  of  nitrate  of  sodium  (see  Table  II.),  were  applied  to  their 
respective  plots  on  March  12.  No  running  of  the  drain-pipes 
occurred  till  after  harvest,  on  Aug.  30. 
The  drain-pipes  of  Plots  3&4,  5,  16,  and  17,  receiving  no 
nitrogenous  manure,  all  ran  on  Aug.  30;  the  water  contained  a 
