36 



SOIL CONDITIONS AND PLANT GRO WTH 



them is of fundamental importance to our subject and must be 

 discussed in some detail. 



Each of the separate processes — assimilation, respiration, 



%Z00 



t 



80 



40 





Fig. 



/O 0° +/0' +^0° +,?0" -^40' +50' 



— *■ Temperature 



-Relation between temperature and assimilation. (Miss Matthaei.) 



etc., gives, so far as is known, curves like Fig. 3, continuous 

 over the whole range of temperature nearly up to the death 

 point. At higher temperatures it is necessary to work for a 



-JO 



+30° +40° +50' 



_ +/<?" +20 



^ — *- Tenvperature 



Fig. 3a. — Relation between temperature and plant growth 



(Bialoblocki.) 



short period only, so as to reduce the injurious effects then 

 produced, but there is no break in the curve. 



For the growth of the plant, however, it is necessary that 

 all the processes should work harmoniously together, and that 



