THE RELATIVE WILTING COEFFICIENTS FOR 
DIFFERENT PLANTS' 
LyMawn J. Briccs anp H. L. SHANTzZ? 
The wide range in moisture content of different soils at the time 
of wilting of the plant cover appears to have been first clearly 
recognized by SAcHs3 in 1859. Later investigators, in extending 
this work, concluded that not only do soils show a wide range in 
moisture retentiveness, but that different groups of plants differ 
widely in their ability to reduce the moisture content of a given soil. 
Thus, the experimental work of Gary,‘ HErnricu,’ Hepccock,® 
and CLEMENTS’, all indicates considerable variation in the moisture 
content of the soil at the time of wilting of different plants, which 
has been interpreted to mean that some plants are capable of 
reducing the moisture content of a given soil to a lower point than 
others; in other words, that the ‘“‘non-available moisture” varies 
according to the kind of plant used as an indicator. In fact, this 
is the view which is usually presented in many of the standard 
works on plant physiology and plant ecology. 
The difference exhibited by plants in this respect has also been 
? Published with the permission of the Secretary of Agriculture. 
2 For discussion of methods and additional matter, see Briccs, L. J., and SHaNtz, 
H. L., A wax seal method for determining the lower limit of available soil moisture. 
Bor. Gaz. dt 210-219. I9QII 
ing coefficient foe different plants and its indirect determination. U.S. 
bene: Agric. Bur. Pl. Ind. Bull. 230. 1912. ; 
he wilting coefficient and its indirect determination, Bot. Gaz. 53: 20-37. 
Igt2. 
3 Sacus, J., Berichte iiber die Sree Thatigkeit an der Versuchstation in 
Tharandt. Landw. Versuchs. Stat. 1: 1850- 
4 Gatn, E., Action de l’eau du 3 sur aa vegetation. Rev. Gen. Bot. 7:73. 1895. 
RICH, R., Zweite Bericht iiber die Verhaltnisse und Wirksamkeit des Land- 
withiaiitek Veruca Staten: zu Rostock. 1894: 29. 
6 Hepccock, G. G., The relation of the water content of the soil to certain plants, 
aia cnet Bot. Surv, Neb. VI. Studies in the vegetation of the state 
1a 
7 ae F. E., Research methods in Ecology. 1905: 30. 
220) [Botanical Gazette, vol. 53 
