HYDRATURE AND PLANT PRODUCTION 



277 



said that decreasing hydrature means diminution of yield, that is : the 

 higher the average osmotic value the low^er the yield. 



Sprinkling experiments carried out by the author in Abu Ghraib, Iraq 

 (1956-58) produced identical results (Kreeb, 1957, 1961a). It was also found 

 that the curve of decreasing yield with increasing average osmotic values 

 shows the form of an e-function (see Figs, i and 2). This means, that the 



0-6 



06 



CM 



E 



01 





02 



13 1A 15 16 



Average osmotic value in atr 



17 



Fig. I. Curve of decreasing yield with increasing average osmotic values in barley 



(Trabot). After Kreeb, 1957. 



Fig. 2. Curves of decreasing yield with increasing average osmotic values in lettuce, 

 turnips and horse beans. After Kreeb, 1958. 



