22 



CIRCULAR NO. 109, BUREAU OF PLANT INDUSTRY. 



Nevertheless, the figures given in Table III show clearly a retarding 

 effect of the more strongly saline soil mixtures. Observations at more 

 frequent intervals than every 24 hours might have shown some retar- 

 dation in mixtures less concentrated than No. 9, although it was noted 

 that emergence was at least as prompt in No. 5 as in Nos. 1 to 4. 



CHARACTER OF GROWTH. 



On April 13, one week after planting, the longest leaf in each glass 

 was measured and the mean of these values for the six glasses of each 

 soil was taken as expressing the growth made in that soil while there 

 was still abundant "available" moisture. Table IV shows the values 

 thus obtained. 



Table IV. — Mean length of the longest leaf in each soil one week after planting. 



These data show a much more marked correlation between the 

 rate of growth of the plants and the salt content of the respective 

 soils than the figures relating to rate of emergence given in Table III. 



In soils Nos. 1 to 8 the seedlings made a good, healthy growth in all 

 the glasses. In Nos. 9 to 1 1 their growth was good in the main, but 

 the plants were smaller. In Nos. 12 to 14 the growth was irregular 

 in the glasses in which any plants emerged, some plants having been 

 small and sickly, while others had made a fair growth and appeared 

 fairly normal. For some reason the average growth was better in 

 No. 13 than in No. 12. 



DETERMINATION OF THE WILTING COEFFICIENT. 



As soon as the plants appeared to be in a wilted condition the 

 soils were collected from the glasses for moisture determination. 



Table V gives the final water content of the soil in each glass in 

 which sufficient growth was made to reduce the water content to 

 anywhere near the wilting coefficient, as well as the mean of these 

 determinations for each soil mixture. For comparison, the mean 

 wilting coefficient is given for each mixture, as calculated from the 

 moisture equivalents at the outset of the experiment. 



[Cir. 109] 



