1064 



EXPERIMENT STATION RECORD. 



described in earlier publications of the station (E. S. R., 8, p. 683; 12, p. 942), is 

 briefly summarized. The later observations here recorded were made by the author 

 at Grand Junction, Colo., in 1900 and at Oxnard, Cal., in 1904. 



The investigations in Colorado indicated that in the virgin soils under test the heavy 

 percentage of alkali lies above the fourth foot, and that the excessive amounts found 

 in the upper foot have been brought there from that depth by shallow irrigation and 

 by the upward leaching of the soil due to seepage. The average of 8 soluble salt 

 determinations upon soils producing either good or fair crops of beets shows a per- 

 centage of 0.036 of chlorids, 0.004 of carbonates, and 0.087 of sulphates, or a total of 

 0.127 per cent in the upper foot of these fields. These figures correspond to 1,440 

 lbs. of chlorids, 160 lbs. of carbonates, and 3,480 lbs. of sulphates, or a total of 5,080 

 lbs. of soluble salts in the upper acre-foot. The yields of beets ranged from 7.76 tons 

 to 20.98 tons, or an average of 8.45 tons per acre, with an average sugar content of 

 16.03 per cent and a purity of 81.8. 



Soils producing poor crops of beets under the same conditions of cultivation and 

 treatment were found to carry much more chlorid in the top foot than was held in 

 the upper 3 ft. of the soils producing fair crops. These data are regarded as showing 

 that the soluble salt content of the soil is the primary cause of the failure of beets, 

 but it is pointed out that the high percentage of alkali is not uniform throughout the 

 locality, and that by proper selection of soils these difficulties may be avoided. 



The strength of the soil solution was determined as based on 20 and 10 per cent of 

 moisture in the soil. It was found that the heavy adobe soil 2 days after irrigation 

 contained from 18 to 20 per cent of w T ater, while several days after irrigation the 

 moisture content had fallen from 8 to 12 per cent and the plants were suffering from 

 lack of water. As shown by the analyses made, the solution in soil with 20 per cent 

 of moisture contained 2.97 per cent of alkali, and with 10 per cent of water in the 

 soil 5.86 per cent. It is pointed out that w T hen the density of a soil solution becomes 

 too great the vitality of the seed is destroyed or, in the case of already growing plants, 

 the passage of water from the soil into the plant is checked. 



At Oxnard, Cal., observations were made in fields with a marked unevenness of 

 stand, which frequently characterizes beet fields on alkali soils. The results on all 

 the different fields pointed to the fact that wherever the chlorid content of the soil 

 approached 0.20 per cent beet culture was unsuccessful. It was further shown that 

 the sulphates had a comparatively limited effect on the growth of beets. The effect 

 of the different salts is more clearly brought out in the following table: 



The effect of different percentages of soluble salts on the growth of sugar beets. 



On this particular field the sugar content of the beets ranged approximately from 

 1 7 to 22 per cent. 



In certain portions of these fields where good beets w r ere produced, practically all 

 the alkali was found in the top foot of soil, where it could have little or no effect on 

 the more delicate feeding roots of the plant, while on adjacent spots producing no 

 beets the concentration of the alkali was essentially the same in the first and the 

 second foot of soil, bringing it within reach of the fibrous- feeding roots. Thise 

 results are regarded as indicating that the distribution of the soluble salts within the 

 soil may be a more important factor than the total quantity of alkali present, and 



