232 BRIGGS AND SHANTZ I WILTING COEFFICIENT OF PLANTS 



a means of computing the wilting coefficient when direct deter- 

 minations are not feasible. 



Wilting coefficient = 

 Wilting coefficient = 

 Wilting coefficient = 

 Wilting coefficient = 



Moisture equivalent 

 1.84(1 ±0.0077" 



Hygroscopic coefficient 

 0.68(1 ±0.018)~ 



Moisture holding capacity — 21 

 2.90(1 ±0.021) 



0.01 sand - 0.12 silt - 0.57 clay 

 (1 ±0.025) 



The second term of the quantity within the brackets shows the 

 probable error of the relationship in each case and constitutes a 

 measure of the relative accuracy of the different methods. 



The moisture equivalent method, in which the measurements 

 are made with the aid of the centrifugal machine exerting a force 

 1000 times that of gravity, is the most accurate and satisfactory 

 of the indirect methods. 



