48 



after which the results vE-.ry although th© average ia above 

 that reached where th*^r« was 14.0 p,T>.nu NO3. (Tliio 

 Bt£t©in@nt is not strictly eorr&ct sines the r-isults W6»r© 

 obtained from 'irainsge water which passed through th© sub- 

 soil Bone distance before entering the drain. doubtless 

 t^-9 amount of NO., given is smaller th^^n wouid have bt-sn 



v> 



secured had tha dr termini ti one been nads where ths roots 

 wsr® feeding ; but the €«aapi-rative r-ssults ^ov.^d probably 

 have not been far dirffxent.) Th© difficulty in securing 

 soluble nitrogon when the amount of NO3 in this soil is 

 below 14.0 p.'.n-i. ie indicated. vany facfors wou^-d affect 

 the limit b%lov; which plants would suffer for lack of 

 soluble nitrogen, one of which would be th@ cloeeness of 

 the roots of the pj.ants. It is probably, the limit for 

 corn would ':e higher than for wheat if th© soil moisture, 

 temperature, a,>d other conditions w«»re the same, 



^'Tien any crop with a close root systera is growing with 

 corn, IS not the corn at an increasing disadvar>t*ir;» as th© 

 limiting f€«rciliz«ng constituent was lowered in the soil ? 



