28 



CIRCULAR NO, 121, BUREAU OF PLANT INDUSTRY. 



season, but salt determinations made at different times show a 

 decided reduction in the salt content of the upper 12 inches of soil. 

 The average salt content of the upper 12 inches of soil on plats 

 M-I-5 to M-I-9, mclusive, in September, 1911, was 0.52 per cent. 

 By September, 1912, the percentage of total salts in the same plats 

 had been reduced to an average of 0.28. 



About 10 acres of the land have been planted to wmter lye for two 

 seasons. Both crops of rye were produced without irrigation, the 

 winter rains and snows giving sufficient moisture. The crop was 

 plowed under m May each year and the land kept in good tilth 

 throughout the remainder of the season in order to prevent the 

 evaporation of water from the surface and the consequent accumu- 

 lation of salt in the upper layer of the soil. 



Fig. (i. -A plat of rye on the Wonieii tract in May, 1912. Rye was grown here in 1911 and 1912, the .sefond 

 crop l:)einK heavier and more uniform than the first. The green crop has been plowed under each year 

 to improve the physical condition of the surface soil. 



Salt determmations have not been systematically made on the 

 rye land, so that it is not known to what extent the salt content of 

 the surface soil has been reduced. The growth of rye (fig. 6) was 

 much heavier and more uniform in 1912 than it was m 1911, and the 

 soil tOth was decidedly better, so that the plowing under of the rye 

 crop appears to have had a beneficial effect. Durmg the season of 

 1913 salt determinations will be made regularly and the salt content 

 of the rye land will be compared with that of the adjacent virgin 

 soil. 



[Cir. 121] 



