260 SOILS: PROPERTIES AND MANAGEMENT 



181. Calculation of the wilting point. — In studying 

 the correlation of this wilting coefficient to soil conditions, 

 Briggs and Shantz 1 advanced the following relationships. 

 Expressed as formula? they represent methods of at 

 least approximating the wilting point from other soil 

 factors. These formulae are arranged in the order of 

 their reliability, based on the data obtained by the 

 authors : — 



1. Wilting point = Moisture equivalent (em)r 2 Q per cent) 



2. Wilting point = Hygroscopic coefficient (em)r 71 per oent) 



.68 



3. Wilting point 



= Water-holding capacity (Hilgard method) ~ 21 (orror 8 3 per cent ) 



182. Relation of texture to the wilting point. — From 

 the data already quoted 2 from Heinrich and from Briggs 

 and Shantz regarding the hygroscopic coefficient and the 

 wilting point, it is evident that a very close relationship 

 exists between the texture of the soil and the percentage 

 of moisture at which plants wilt. The finer the soil 

 texture, the higher is the wilting point. The following 

 figures, from Briggs and Shantz, 3 bring out the point very 

 clearly : — 



1 Briggs, L. J., and Shantz, H. L. The Wilting Coefficient 

 for Different Plants and its Indirect Determination. U. S. D. 

 A., Bur. Plant Indus., Bui. 230, pp. 56-77. 1912. 



2 This text, paragraph 178. 



3 Briggs, L. J., and Shantz, H. L. The Wilting Coefficient 

 for Different Plants and its Indirect Determination. U. S. D. 

 A., Bur. Plant Indus., Bui. 230, pp. 26-33. 1912. 



