SOILS FERTILIZERS. 223 



teotlon of the crop against drought is iu almost exact proportion to the total 

 available soil water within the reach of the crop. 



"Grass crops (alfalfa and brome grass) dry the subsoil to such an extent 

 on the substation farm that the first crop following grass is wholly dei)endent 

 on the season's rainfall for its moisture supply. 



"A rainfall of from a quarter to a half inch may have a decidedly beneficial 

 effect upon a growing crop and is of great assistance in securing a good stand 

 at seeding time. Such a rainfall has little or no eifect in increasing the water 

 in the lower soil unless the surface is already moist from previous rains. Less 

 than a half inch of rain falling on a dry soil mulch does not wet the soil below 

 the mulch and is soon evaporated by the sun and wind." 



Soil evaporation, 11. W. Thornton (Agr. Jour. Cape Good Hope. .i6 (1!)W). 

 So. J, p}). 3-J2-.l'/7'. figs. 5). — Experiments at the Robertson Experiment Station 

 with jacketed cylinders similar to those used in investigations on evaporation 

 by this Office are reported. The princii)al object of these experiments was to 

 determine the effect of cultivation on the conservation of soil moisture. The 

 soil in the cylinders received varying amounts of water and some received 

 surface cultivation when dry enough to permit it and others were left without 

 cultivation. 



The results show that the cultivated cylinders lost far less water than the 

 uncultivated cylinders. " It is clearly shown that a vast amount of moisture 

 can be saved by cultivation, amounting in the cool month of September to over 

 half an inch of rainfall, though there is little doubt that the evaporation during 

 the heat of summer will be very much higher, but even taking half an inch per 

 month gives a total of G In. per annum, which is an amount that can not be 

 despised. This experiment shows the great benefit derived from cultivation in 

 dry land farming." 



An introduction to the study of the soil solution, F. K. Cameron {Jour. 

 Phils. Chciii.. I't {I'JIO). Xo. .}, pp. 3.20-312. figs. 3).— This article attempts to 

 give ■' an outline of our present knowledge of the chemical principles involved, 

 with such discussion of the physical and biological factors as is essential to an 

 orderly pi-eseutation of the subject." It is based to a large extent upon investi- 

 gations which have been reported from time to time In bulletins of the Bureau 

 of Soils of this Department. 



The transfer of heat in soils, H. E. Patten (Set. Anicr. Sup., 69 (1910), No. 

 1789, pp. 253. 2-j'i. figs. //). — This is a brief account of apparatus and methods 

 used in investigations which are reported In detail in a bulletin of the Bureau 

 of Soils of this Department previously noted (E. S. R., 22, p. 20). 



The variable character of the vegetation on basalt soils, H. I. Jensen 

 (Proc. Linn. Soc. N. 8. Wales, S.'f {1909), pt. 4, PP- 713-720).— The various types 

 • •f vegetation found on basalt formations are described and an attempt is made 

 10 correlate the plant distribution with soil characteristics. A table is given 

 showing the average chemical composition and physical properties of typical 

 soils of various geological formations as compared with the basalt soils on 

 which the observations reported were made. 



The author's observations show in general " that the defect of basaltic soils 

 is never want of plant food. The worst faults are high water capacity, which 

 causes the drowning of plants in wet weather; and the low capillary power, 

 which impedes a renewal of soil moisture in droughty seasons." 



Pineapple soils, W. P. Kelley (Hawaii Sta. Rpt. 1909, pp. 58-63). — Chem- 

 ical examinations of certain black lands on which pineapples did not grow well 

 showed the presence of from 2.43 to 9.74 per cent of manganese CNInsOi) and 

 indicated a close relation between the manganese content of the soils and the 

 52065°— No. 3—10 3 



