624 EXPERIMENT STATION RECORD. [Vol. 87 



1916 but not mulched lost very little more water than one mulched 2 In. deep. 

 A 6-in. cultivation on spring-plowed and a 2-in. cultivation on fall-plowed dry- 

 farm land seemed to conserve the moisture best 



Subsoiling 15 in. deep had little Influence on the moi.sture; spring disking 

 was a rather distinct benefit. Spring plowing under dry-farming conditions 

 at Nephi conserved moisture better than fall plowing, this difference in favor 

 of spring plowing being shovm more below the first foot than in the first foot, 

 and more in the summer and fall than in the spring. 



A precipitation a.s small as 0.1 in. under dry-farming conditions could not be 

 detected in moisture determinations soon after, but when as much as 0.5 in, 

 fell within a short time an increase in moisture was noticed to a depth of 6 ft. 



" When freely supplied with water, a soil with a high initial percentage of 

 moisture wUl come to a moisture equilibrium sooner than a drier one, but if 

 given time the drier soil will absorb a greater quantity through a long distance 

 either upward or downward than will the wet one. The rate of moisture pene- 

 tration In the first 10 days was nearly twice as great with initial percentages 

 above 15 as with 6 or below, and nearly twice as rapid after a 15-in. irriga- 

 tion as after a 5-Ln. one. Under the most favorable conditions 7 ft. wa.s in- 

 fluenced in 10 days. Moisture movement from soils of optimum moisture con- 

 tent Into soils of differing initial percentages varied to an extent Inversely as 

 the Initial content of the dry soil. At th« end of six weeks, however, tlie 

 amount of water actually In the soils still varied directly as the initial per- 

 centage. The higher tlie percentage of moisture In the soil supplying the water 

 to a dry soil, the more rapidly and farther from the som-ce of water did the 

 moisture move. Even when the .source of water was an unsaturated soil, 

 greater and faster movement took place when the water was movhig downward 

 than upward. When tlie quantity of soil yielding the water was so small as to 

 make the total moisture contont of both moist and dry soils very low if equally 

 distributed, the effect of gravity was not great. 



" Moisture from a nearly saturatetl soil moved a greater distance Into loam 

 than into sand in 189 days and into sand farther than into clay. The clay, 

 however, contained more moisture In the layer of soil next the water supply 

 than the others, and sand contained by far the least. Sand, with 7.77 per cent 

 of moisture, gave up Its moisture to loam much more readily than did loam with 

 31.09 or clay with 24.02 per cent of moi.sture. The rate of rise of moisture 

 from soils of varying fineness when u.sed either as water sources or water ab- 

 sorbexs varied inversely with the fineness. Water rose to a height of over 30 

 in. in a loam soil from a moi.'t sand In 94 days, while from a moist clay it rose 

 little more tlian 6 in. in this length of time. In all soUs the most rapid rise of 

 the water was during the period suon after being placed in contact with the 

 water. Although Uie rise of the moisture was more rapid in the sand and loam 

 than in the clay, the rise continued steady longer in the clay than in the othei's." 



Adsorption by soils, J. E. Habris (Jour. Phys. Chcm., 21 (1917), No. 6, pp. 

 45^-473). — Further experiments at the Michigan Experiment Station on the 

 subject (E. S. R., 31, p. 814), using uniform samples of sandy loam soil, are 

 reported. The purpose was to secure additional evidence that the cause of soli 

 acidity is due to colloidal adsorption or to the presence of true acids, and to 

 secure data on the action of fertilizer salts. 



It was found that " when a soil or kaolin Is treated with salt solutions of 

 varying concentrations the quantities of the cation adsorbed follow very closely 

 the adsorption Isotherm represented by the equation x/m—ac^. Indicating that 

 the action Is one of adsorption and not of double decomposition. 



" When the soil was treated with different salt solutions it was found that the 

 number of equivalents of the diffwent cations adsorbed was not the same. The 



