16 



BULLETIN 135, U. S. DEPARTMENT OF AGRICULTURE. 



Table XIII. — Average total salt content of soil to a depth of 4 feet on plats which had 

 received treatment according to the first, second, and third methods, respectively, and of 

 adjacent virgin soil, in 1913. 



Soil. 



Method. 



First. 



Second. I Third. 



Virgin 

 soil. 



Number of borings . 



Layer of soil: 

 Top 3 inches . 

 3 to 6 inches . . 

 6 to 12 inches. 



0.23 

 .28 

 .39 



Average, first foot. 



12 to 24 inches 



Average, top 2 feet. 

 24 to 36 inches 



Average, top 3 feet . 

 36 to 48 inches 



Average, top 4 feet. 



.32 



.85 



.58 

 1.31 



.83 

 1.29 



.94 



0.25 

 .34 



.44 



1.01 

 .72 

 1.75 

 1.07 

 1.45 

 1.16 



mi 



0.25 

 .29 

 .43 



0.65 



.92 



1.54 



. 35 



1.16 



.74 

 .54 

 1.37 

 .82 

 1.59 

 1.01 



1.83 

 1.49 

 2.08 

 1.69 

 1.79 

 1.71 



From Table XIII and figure 7, it appears that the first method, that 

 of plowing under rye as green manure and keeping the soil clean culti- 

 vated after plowing, has been the most effective in reducing the salt 

 content of the upper 4 feet of soil. It appears also that the third 

 method, alternate irrigating and cultivating combined with heavy 

 applications of barnyard manure, has been second in effectiveness. 

 This is assuming that the amount of salts was the same on all parts of 

 the field before the ground was broken up in 1910. No determina- 

 tions were made of the salt content before the ground was broken up. 



Oroj)s grown in 1913. — It is not possible to make direct comparisons 

 of the crop returns secured in 1913 on the plats which had received 

 different treatments in previous years. As already shown, the plats 

 receiving the treatments according to the first method produced very 

 satisfactory results with winter wheat, sugar beets, and alfalfa; those 

 treated by the second method produced fair returns from oats and 

 alfalfa; and the plats treated in accordance with the third method 

 produced spring wheat and oats satisfactorily and a fair yield of 

 sugar beets. The chief point to be considered in connection with the 

 crop returns in 1913 is that the behavior of all the crops grown indi- 

 cated that the soil on all the plats which have received treatment has 

 been greatly benefited, and that so far as the surface soil is concerned 

 the treated land has been fairly well reclaimed. Whether the recla- 

 mation is to be permanent will depend on future conditions, of which 

 drainage is probably the most important. 



Cost. — A comparison of the approximate cost per acre of the differ- 

 ent methods is given in Table XIV. 



