620 EXPERIMENT STATION RECORD. 



throughout the second winter. The temperature of the cultivated plat rose 

 slightly higher than that of the uncultivated, after thawing, and continued 

 to be slightly higher during the early part of the spring season or up to about 

 the middle of May, and then the uncultivated plat become the warmer and 

 remained so throughout the whole summer. During the fall both plats had 

 about the same temperature with a slight difference in favor of the uncultivated 

 plat. The dilTerence in temperature between these two plats was explained 

 upon the following general facts: (1) Different rate of evaporation, (2) differ- 

 ent rate of heat conductivity, (3) difference in temperature at the lower 

 depths, and (4) the effect of the dry mulch of the cultivated soil. 



" Salt solutions had a very marked influence on the rising and lowering of 

 soil temperature. Different salt solutions of the same density or the same 

 solution of different densities raised the soil temperature considerably. Their 

 influence was also very pronounced on the rate and degree of lowering of tem- 

 perature, as well as on the rate of thawing. 



" The different kinds of manure raised the soil temperature differently — horse 

 manure the most, sheep manure the least, and the cow manure intermediate. 

 In every ca.se the greatest rise took place in the first three or four days. The 

 rise increased with the increase in quantity. The degree of rise is probably 

 Insignificant for practical conditions." 



A list of 41 references to literature on the subject is given. 



Soil moisture, R. E. Willard and E. P. Humbert (New Mexico Sta. Bui. 86, 

 pp. 86, figs. 11). — ^This bulletin gives the results of several years investiga- 

 tions on the movement of water in soils in field plats and in tanks. The field 

 plats were one-twentieth of an acre in size. The tanks were of galvanized iron, 

 approximately 27 in. in diameter and 4 ft. in depth. The tanks were sunk to 

 their tops in galvanized iron jackets in the soil and were so arranged as to be 

 readily withdrawn and weighed. Two lysimeter tanks were provided for 

 studies on percolation and capillarity. These were similar in con.struction to 

 those described except that they contained a false bottom, beneath which was a 

 space capable of holding several gallons of water which could be drawn off and 

 measured. " Two tanks 3 ft. in depth and 3 ft. square were provided for the 

 purpose of determining the evaporation from the surface of water when it is in 

 the direct sunlight and had the free passage of air over it, and also from the 

 surface of water when the wind is not allowed to pass freely over it. The first 

 of these is set so that the top is level with the surface of the ground, the second 

 is similarly placed but is surrounded by glass so that the passage of air across 

 its surface is prevented." Irrigation water in varying amounts was applied to 

 the plats by the flooding and furrow methods. 



It was found that while the soils experimented with " possess some capillary 

 properties, these are apparently less than in more humid regions. The maxi- 

 mum rise from water through sandy loam soil was about 32 in. and through 

 adobe clay 50.5 in. The movement of moisture from wet soil to dry was very 

 slight although where a crop of wheat was growing moisture rose from wet soil 

 below, to the region of the roots, through 30 in. of soil. This was the maximum 

 observed. 



"As other investigators have observed, the rise of moisture is more rapid in 

 coarse soil than in flne-textured soils but the ultimate ri.se is much greater in 

 the heavy soils. . . . 



" Loss of irrigation water by seepage in these sandy loam soils was In pro- 

 portion to the amount of water applied. When crops were grown on uniform 

 sandy loam scarcely any of the irrigation water penetrated below 4 ft. from 20 

 in. of irrigation during the season as indicated from the tank data. Where the 

 soil did not support a crop nearly one-seventh of the 20 in. was lost by seepage. 



