HYDRATURE AND PLANT PRODUCTION 



283 



2 3 



Suction tension 



Fig. 9. Curves showing the relation between length of shoot and needles, dry weight, 

 net assimilation rate and increasing suction tension in the soil. After Sands and 

 Rutter, 1959. 



osmotic value rises by i atm. More resistant are barley, sugar beet, and 

 alfalfa. The accuracy of the given figures is not too great, as some of the 

 experiments have been made without replication. But it is conspicuous, 

 that in the case of barley, the data of Bauman (Canada) and Kreeb (Iraq) are 



Table 3 



Diminution of yield of various crops per increase of the average osmotic value (H^) by 



I atm in percent maximum yield 



