344 EXPERIMENT STATION RECORD. 



"The custom in this valley of partially suh.stitutiii",'' irri<iatiou for cultivation is not 

 without some foundation. The moisture C(mtent of the soil and the yield of corn 

 are not materially increased by frequent surface cultivations on these soils. 



" Subsoiling in these tests has not proved to be of marked advantage. 



" On this soil, clay loam, corn wilts when the amount of moisture falls nuich below 

 20 per cent. 



"The benefit derived from winter irrigation will depend mainly on the texture of 

 both surface and subsoil. In these tests its benefit was confined mainly to insuring 

 good germination." 



In an attempt to determine the effect of frequent cultivation on the soil moisture, it 

 was found to be " practically impossible with ordinary implements to produce a dust 

 mulch on the clay loam and clay soils" experimented with, which are characrteristic 

 of the Mesilla Valley. 



Electrodes of the moisture apparatus placed at different dejaths (3 to 18 in.) in the 

 soil within 3 ft. of irrigated plats "showed no appreciable rise in the moisture con- 

 tent of the soil during the season." The conclusion is therefore drawn that " in the 

 clay loam soils of the Mesilla Valley lateral percolation is very slight." 



On the meclianical analysis of soils, T. Schloesing ( Compl. Rend. Acad. Sci. 

 Parl.^, 136 {190S), No. :2<;, pp. 160S-1613; 137 {1903), Nos. 6, pp. 369-374, fig. 1; 7, 

 pji. 309-402). — The author shows as a result of a continuation of jirevious investiga- 

 tions (E. S. R., 14, p. 18) that it is XMjssible to separate the fine sand of cultivated 

 soil {krre vcgctale) into a number of grades of decreasing degrees of fineness by noting 

 the time required for deposition from water of a given depth and the weight of the 

 deposits formed during successive intervals of time. 



A method of mechanical analysis of soils based upon this principle, with the appa- 

 ratus required, is described. The sample of soil previously treated on the filter with 

 weak nitric acid to remove lime, and afterwards with weak ammonia and freed from 

 coarse particles by decantation, is shaken up in water in a cylinder 33 cm. long. 

 This cylinder is provided with devices for automatically maintaining a constant level 

 of water, and for draining off the deposits formed through the bottom into recepta- 

 cles drawn under the outlet of the cylinder l)y clockwork arrangement. The opera- 

 tion requires about 21 hours and is practically automatic. It is not claimed that 

 exact results are obtained by the method, although as the average of the results with 

 various soils 7 grades of sand were separated, varying in diameter of particles within 

 the following limits: (1) 70-90 mm., (2) 65-80 mm., (3) 50-70 mm., (4) 30-50 mm., 

 (5) 20-35 mm., (6) 15-20 mm., (7) 5-15 mm. Particles smaller than 5 mm. in 

 diameter remain in suspension indefinitely. 



A contribution to the study of the assimilation of the minerals of the soil 

 by plants, J. Crochetelle (Ann. Set. Agroit.,^. ser., 1902-3, II, Xo. 1, jyp. 33-44)- — 

 This article reports studies of the basicity of different soils (calcareous and noncal- 

 careous) by means of citric acid, as used in Dyer's method for available plant food 

 in soils, and of the assimilation of phosphoric acid by chlorotic plants. The deter- 

 mination of the lime content of soils by means of dilute citric acid was found to be 

 very unreliable in the case of granitic soils, but very useful in case of soils producing 

 chlorotic plants. Data are reported which indicate that plant chlorosis is due to 

 interference with phosphoric acid assimilation by an excess of lime in the soil 

 neutralizing the root secretions of the plants. 



Practical methods for m.aintaining the fertility of the soil, ^^^ Saunders 

 {Connecticut State Bd. Agr. Ept. 1902, pji. 203-228). — -An argument in favor of better 

 care and utilization of farm manures. 



Soils — their requirements and improvements, H. J. Wheeler {New Jersey 

 State Bd. Agr. lipt. 1902, pp. 127-158, pis. 5). — A general discussion of this subject 

 based mainly upon the investigations of the experiment stations, especially that of 

 Rhode Island. 



