168 
INVESTIGATIONS ON EOTHAMSTED SOILS. 
Although there have not been large crop residues in series 2 and 
series 3 to reenforce the natural nitrogen, there have been, as will be 
seen on reference to Table 87, throughout but small crops, and there- 
fore small demands upon the soil nitrogen, whether natural or 
manurially supplied. 
On the plats receiving farmyard manure (plats 1 and 2) the 
nitrogen is throughout, as we should expect, far greater in propor- 
tion in every series than on the other plats, the largest quantities of 
nitrogen being found in series 4 and series 5, in which the dressings 
of farmyard manure have been supplemented by dressings of rape 
cake. 
