WAX-SEAL METHOD FOE DETERMINING WILTING COEFFICIENT. 21 

 Table VI. — Comparison of the wilting coefficient for seedling and old grass plants. 



Species. 



Old 

 plants. 



Species. 



Seed- 

 lings. 





9.6 

 9.6 



10.4 

 9.7 

 10.9 

 10.3 

 10.5 

 8.8 

 8.4 

 9.3 

 9.0 

 9.3 

 9.7 

 9.0 

 9.9 

 9.2 

 9.6 

 9.2 

 8.9 

 8.7 

 10.1 

 9.6 

 10.2 

 9.8 

 9.5 

 9.4 

 10.6 

 10.7 

 9.7 

 9.7 

 11.4 





9.4 



Do 



Do 



8.8 



Do 



Do 



9.6 



Do 



Do... 



10.2 



Do 



Do 



Do 



9.5 



Do 



9.5 



Do 



Do 



9.7 



Do 



Do 



Do 



8.9 



Do 



9.5 



Do 



Do.... 



9.3 



Do 



Do 



8.6 



Do 



Do 



9.0 



Do 



Do 



9.5 



Do 



Do...; 



9.5 



Do 



Do 



9.1 



Do 



Do . 



8.9 





Do 



9.5 



Do 



Do 



Do 



Do 



9.1 



8.9 



Do 



Do . 



10.1 



Do 



Do 



9.5 





Do 



10.3 



Do 



Do 



9.3 



Do 



Do... 



9.0 



Do. . 



Do 



9.3 



Do 



Do 



9.0 



Do 



Do 



9.3 



Do. 



Do 



9.6 



Do 



Do 



9.4 



Do 



Do 



9.5 



Do.. 



Do 



9.9 



Do 



Do 



10.1 





Do 



9.8 







9.6 





Do 



9.7 





Do 



9.6 





Stipa vasevi 



9.3 





Do....* 



9.6 





Do 



9.7 





Sitanion hvstrix 



9.2 





Do 



9.6 





Do 



9.3 





Aristida longiseta 



9.5 





Do 



9.7 











9.7 



± .09 



± .46 



9.5 





Probable error of mean 



± .04 



Probable error of single determina- 

 tion 



Probable error of single determina- 

 tion 



± .25 









Difference of means, 0.2±0.1. 



Table VII gives a summary covering all the wil ting-coefficient 

 determinations made upon seedlings and old plants. The data upon 

 which this summary is based are given in detail in later tables, and 

 only the ratios showing the relative differences in the wilting coefficient 

 are here given for each crop. Reference to the weighted means * will 

 show that the mean ratio of the wilting coefficient for old plants is 

 0.03 higher than the mean ratio obtained for seedlings. 



We may conclude then that the wilting coefficient is the same, 

 within the limits of experimental error, for a plant in all stages of 

 development. In other words, the soil-moisture content at the 

 wilting point is not dependent to any material degree upon the age 

 of the plant. 



1 In determining the final mean value, each ratio was included once for each determination used in 

 establishing that ratio. 

 230 



