SOILS FERTILIZERS. 421 



The factor which controls the moisture content of the soils is held to be the 

 relative sizes of the soil particles. " The texture of the soil is, therefore, an 

 index of its behavior in relation to moisture in the field. For this reason, 

 amongst others, there is a texture of soil which may be regarded as the optimum 

 for certain plants exactly as there is an optimum proportion of soil moisture 

 for such plants." 



Moisture equivalent determinations and their application, L. J. Beiggs and 

 J. W. McLane {Proc. Amer. Soc. Agron., 2 (WIO), pp. 138-lJf7, pi. i).— The 

 authors discuss the use of moisture equivalent determinations (E. S. R., 19, 

 p. 416) in soil classification and in interpreting field determinations of soil 

 moisture. 



Although it is not urged that the moisture equivalent determinations should 

 supplant any other physical measurements made in connection with soil classi- 

 fication, it is believed that the moisture relationship of the soil is expressed 

 " far more definitely by means of the moisture equivalent than by mechanical 

 analysis. In determining the moisture equivalent, we are not only measuring 

 directly the property which we wish to compare, but we are dealing with 

 single-valued expressions instead of trying to interpret the complex series of 

 numbers represented by the mechanical analysis." 



It is pointed out that determinations of the moisture equivalent make it 

 possible to decide whether irregularities in field determinations of soil moisture 

 are due to changes in soil texture or to the movement of soil moisture. " If 

 the ratio of the moisture equivalent agrees with the ratio of the observed 

 moisture content within the limits of experimental error, then the irregularity 

 was due simply to striking a pocket of soil having a different texture, and the 

 2 samples are in actual capillary equilibrium. If, on the other hand, the 

 moisture equivalents are the same, a movement of moisture has taken place." 



Moisture and nitrate relations in dry land agriculture, H. O. Buckman 

 (Proc. Amer. Soc. Agron., 2 {1910), pp. 121-138, figs. 4). — The results of deter- 

 minations of the moisture and nitrate contents in Montana soil plats under 

 different systems of cropping and fallowing used in dry farm practices are 

 reported. 



The results in general show that fallowing conserved the water supply and 

 increased the nitrate content of the soil. Intertilled crops after fallow did not 

 seriously deplete the soil for a succeeding grain crop, either in moisture or 

 nitrates. The author believes that enough moisture can be conserved in the 

 soil to cause the decomposition of either green or barnyard manure and that, 

 therefore, the fertility problem of arid lands hinges upon moisture conservation 

 and a rational rotation embracing legumes and manure if the latter is available. 



Composition of the drainage water of a soil with and without vegetation, 

 T. L. Lyon and J. A. Bizzell (Jour. Indus, and Engin. Chem., 3 (1911), No. 10, 

 pp. 11,2, 11,3; abs. in Jour. Soc. Chem. Indus., SO (1911), No. 21, p. 1211).— 

 Determinations of the amount and composition of summer and winter drain- 

 age in 1909 and 1910 from concrete pits filled with 3^ tons of clay loam soil, 

 some of which were planted to oats and com and others left bare, are reported 

 and discussed. 



The total solids in the winter drainage from bare soil were 3 times as 

 great as in drainage from j^lanted soil. The nitrogen was 12 times as great, 

 amounting to about 100 lbs. per acre in uncropped soil from October 1 to May 1, 

 and to about 8 lbs. per acre in cropped soil during the same period. Of the 

 cropped soils the largest amount of available nitrogen was found under corn. 

 Nitrate formation occurred largely in midsummer, although nitrates appeared 

 most abundantly in the winter drainage. The loss of calcium was twice as 

 great from bare soil as from cropped soil. Practically the same ratio of loss 



