20 WILTING COEFFICIENT FOR DIFFERENT PLANTS. 



Table V. — Effect of the age of wheat plants on the wilting coefficient — Continued. 





Wilting coefficients of plants at stated ages. 



Soil number. 



20 to 30 days. 



75 to 80 days. 



104 days. 





Actual. 



Ratio, 

 actual to 

 average. 



Actual. 



Ratio, 

 actual to 

 average. 



Actual. 



Ratio, 

 actual to 

 average. 





f 5.1 

 4.9 

 4.9 

 4.7 

 5.0 

 4.7 



f 9.7 

 9.7 

 9.9 

 10.1 

 9.7 

 9.8 

 9.6 



f 14. 1 

 14.7 

 14.3 

 14.7 

 13.4 

 14.6 

 13.1 

 13,5 



f 16.3 

 16.9 

 16.8 

 16.4 

 15.5 

 15.7 

 17.3 

 15.6 

 16.0 

 16.0 



1.07 

 1.03 

 1.03 

 .99 

 1.05 

 1.03 



1.01 

 1.01 

 1.03 

 1.05 

 1.01 

 1.02 

 1.00 



1.01 

 1.06 

 1.03 

 1.06 

 .96 

 1.05 

 .94 

 .97 



1.00 



1.04 



1.03 



1.01 



.95 



.96 



1.06 



.96 



.98 



.98 



4.6 



0.97 



4.3 

 4.6 



0.90 

 .97 



3 







































4 



9.3 



9.4 

 9.4 



1.01 



!98 



9.3 

 9.3 

 9.4 



.97 

 .97 

 .98 



































13.7 

 14.0 



.99 

 1.00 



13.7 

 13.4 

 14.0 



.99 



.96 



1.00 



5 



















































16.2 

 16.3 

 16.7 



.99 

 1.00 

 1.02 



16.2 

 16.3 

 16.7 



.99 

 1.00 

 1.02 



6 











































































•1.01 

 ± .004 



± .028 





.99 

 ± .005 



± .019 





.98 



Probable error of mean 









± .007 



Probable error of a single determi- 









-t .026 













Similar determinations were made with seedlings and old grass 

 plants, but the same species were not available for use in both 

 experiments. These determinations are given in Table VI. The 

 soil used throughout these determinations was the same, so that the 

 observed wilting coefficients can be directly compared. In this case 

 the seedlings gave a slightly lower mean wilting coefficient than the 

 older plants. This is probably due to the slightly better root distri- 

 bution on the part of the seedlings, which were planted rather 

 thickly. The difference, however, is only 0.2 ±0.1 per cent, 1 so 

 that the determinations are in practical agreement. 



1 The probable error of the difference of two numbers, each of which is affected with a probable error, 

 is equal to the square root of the sum of the squares of the two probable errors. 

 230 



