622 EXPERIMENT STATION RECORD. [VoL 41 



this it was concluded that this clay has a more individual chemical composi- 

 tion than that obtained by mechanical analysis according to the old Schloesing- 

 Grandeau method, and that chemically this clay does not correspond to pure 

 kaolin but progressively approaches it. 



Studies of water absorption, percolation, evaporation, capillary water 

 movement, and soil erosion under field conditions, M. P. Miller and F. L. 

 DULEY (Missouri Sta. Bui. 163 {1919), pp. 65, 66). — The preliminary results of 

 an experiment in which a series of plats was subjected to different systems 

 of cropping and cultivation to determine their effects upon water entering the 

 soil and upon soil erosion showed that the amount of water running off the land 

 during the summer of 1917 from the uncultivated plat was 51.4 per cent of the 

 total rainfall, or about twice the amount which ran off the cultivated plat and 

 more than four times the amount leaving when the plats were kept in grass. 

 The erosion from the bare plat where the weeds were kept down was only 

 slightly greater than that from the cultivated land in spite of the fact that 

 the run-off was greater, but the amount of run-off from the bare plat was 

 nearly thirty times as much as that from the plat kept in sod. The other plats 

 which are not quite so extreme in treatment, such as those in corn and those 

 in small grain, have amounts of run-oft" which are intermediate between these. 



An investigation of soil water, E. McK. Taylok {Essex Ed. Com., East 

 Anglian Inst. Af/r., Chelmsford, Bui. 25 {1919), pp. 7). — This pamphlet de- 

 scribes a method of obtaining soil water samples by burying pads of absorbent 

 filter paper in the soil for definite periods of time and then extracting the ab- 

 sorbed soil solution by pressure from the pads ; and reports analyses of such 

 soil water samples obtained from (1) a derelict soil growing grass for 35 

 years, (2) a productive chalky bowlder clay soil unfertilized for 5 years, (3) 

 a highly cultivated chalky bowlder clay soil unfertiUzed for 7 years, and (4) 

 a wet cultivated soil. 



A comparison of the analyses of the soils and the corresponding soil waters 

 showed that although the organic matter content in the first soil was higher 

 than in the other three soils, the organic matter contents of the soil water of 

 the other three soils were greater than in the water from the first soil. The 

 second and third soils contained less potash than the first soil, but their soil 

 water contained more than the water from the first soil. The derelict soil 

 water also contained a higher percentage of ii-on than those from the three 

 fertile soils. 



It is concluded that the composition of the soil water is not that which 

 would be inferred from chemical analysis of the soil. 



Moisture studies at the Leffingwell Rancho, J. R. Allison {Cal. Citrogr., S 

 (1918), No. 12, pp. 290, 308, figs. 6). — This article deals primarily with appa- 

 ratus and methods used in making soil moisture studies. Data obtained are 

 also reported, indicating that trees growing upon a heavy soil are quickly 

 damaged by too liberal use of water. It is believed that it is often much better 

 to have the available soil moisture somewhat below the theoretical optimum 

 or moisture equivalent, preferably about 5 per cent above the wilting coefficient. 

 This seems to be especially true of heavy soils which have the property of in- 

 creasing in volume on becoming wet and contracting on drying. 



Effect of soil alkali on plant growth, F. S. Harris (Trans. Utah Acad. Sci., 

 1 (1908-1917), pp. 131, 132). — This is a summary of the results of 18,000 de- 

 terminations on the effect of alkali in the soil on the germination of seeds and 

 the growth of plants. 



It was found that only about one-half as much alkali was required to inhibit 

 the growth of crops in sand as in loam. Crops varied greatly in their relative 



