24 



WILTING COEFFICIENT FOE DIFFERENT PLANTS. 



Table IX. — Effect of sun and shade on the wilting coefficient for Kubanka wheat in 



soil No. 26. 



Observation. 



Sun. 



Shade. 



Observation. 



Sun. 



Shade. 



1 



8.9 

 9.1 

 9.3 

 8.8 

 9.5 

 8.9 

 9.4 

 9.5 

 9.4 



9.0 

 8.7 

 9.1 

 10.0 

 9.8 

 9.1 

 9.3 

 9.9 

 9.7 



10 





9 1 



2 



11 





9.7 



3 



! Mean 







4 



9.2 



± .063 



± .19 



9.4 



5 



Probable error of mean 



Probable error of single obser- 



± .09 



6 



7 



± .29 



8 





0.2±0. 11 



9 



1 











RELATION OF SOIL-MOISTURE CONTENT DURING GROWTH TO THE WILTING 



COEFFICIENT. 



The observations recorded in Table X were made to determine 

 whether the wilting coefficient was influenced by the amount of soil 

 moisture available to the plant during its period of growth. The ex- 

 periments were made with Turkey Ked and Bluestem wheat. The 

 water content of the soil during the period of growth was maintained 

 practically constant in each pot, the pots being weighed daily and 

 water added to replace that which had transpired. The moisture 

 content of the different pots during the period of growth ranged from 

 12 to 36 per cent, as shown in column 1 of the table. The plants were 

 grown for a period of 61 days. Watering was then discontinued and 

 the plants were allowed to wilt, when moisture determ in ations were 

 made. The results of the wilting-coefficient determinations are given 

 in columns 2 and 4 of the table, and the departure of each determina- 

 tion from the mean of the series is shown. The distribution of the 

 plus and minus departures gives no indication that the initial moisture 

 content has any influence on the wilting coefficient. 



Table X. — Effect of different moisture contents during the period of growth (61 days) 

 on the wilting coefficient for wheat in soil No. 4- 





Turkey Red wheat. 



Bluestem wheat. 



Water content during period of growth (per cent). 



Coefficient. 



Departure 

 from mean. 



Coefficient. 



Departure 

 from mean. 



12 







8 8 

 8.9 

 8.7 

 9.4 

 9.6 

 9.5 

 9.4 

 9.0 

 9.2 

 7.9 

 8.0 

 9.2 



-0.2 



14 



8.8 

 9.5 

 9.6 

 9.8 

 9.1 

 9.0 

 10.0 

 9.7 

 8.5 

 9.6 



-0.5 

 + .2 

 + .3 

 + .5 



- .2 



- .3 

 + .7 



- .4 



- .8 

 + .3 



- .1 



16 



- .3 



18 



+ .4 



20 



+ .6 



22 



+ .5 



24 



+ .4 



26 



.0 



28 



+ .2 



30 



-1.1 



32 



-1.0 



34/. 



+ .2 



36 



8.5 



- .8 













9.3 

 ± .011 

 ± .36 





9.0 

 ± .011 

 ± .37 























230 



