166 SOIL SCIENCE [BoT. Absts., Vol. IX, 



was liberated from the low-potassium greensand. In composts containing manure the total 

 amounts of potash recovered in the water extracts varied from 9.1 to a maximum of 41.3 per 

 cent of the total initial amount present. — F. M. Schertz. 



1056. McCooL, M. M., and L. C. Whiting. Some studies on the rate of formation of 

 soluble substances in several organic soils. Soil Sci. 11: 233-247. 4- fig- 1921. — By means 

 of the freezing point method the rate of formaton of soluble material was determined in 7 

 organic soils under different moisture and temperature conditions and at different depths. 

 At any given moisture content, higher temperatures tend to bring more material into solution 

 and lower temperatures decrease the rate of formation. In general, the ability to yield solu- 

 ble materials decreased regularly from the surface to the water-table. The zone of weathering 

 and the region of greatest activity closely coincide. — W. J. Robbins. 



1057. MacIntire, W. H., and C. A. Mooers. A pitless lysimeter equipment. Soil 

 Sci. 11:207-213. PI. 1-3, fig. 1. 1921. — A lysimeter system not requiring a concrete enclosure 

 and costing $500 for a 12-unit system is figured and described. It consists essentially of a 

 pair of cylindrical iron tanks, the inner of which holds the soil. Arrangements are made for 

 removing the leachings from the outer tank by means of a pump. — W. J. Robbins. 



1058. MacIntire, W. H., F. J. Gray, and W. M. Shaw. The non-biological oxidation 

 of elemental sulphur in quartz media. Soil Sci. 11:249-259. 1921. — Elemental sulphur will 

 oxidize upon moist contact with relatively pure quartz under both aerobic and CO2 anaerobic 

 conditions. Metallic iron depresses the oxidation, limonite accelerates it. Several carbon- 

 ates under aerobic conditions increase the oxidation. Elemental sulphur may be oxidized 

 to sulphates in a silicious medium solely by chemical reactions. — W. J. Robbins. 



1059. Peterson, Alvah. Some soil fumigation experiments with paradichlorobenzene 

 for the control of the peach tree borer, Sanninoidea exitosa Say. Soil Sci. 11: 305-319. PL 1, 

 Ifig. 1921. — If the soil temperature is 55-G0°F. and the soil not too wet, f to 1 oz. of para- 

 dichlorobenzene will kill 90-100 per cent of the peach-tree borers. It can be safely applied 

 to trees 6 years of age or older. It should be placed in a narrow band about the base of the 

 tree approximately 2 inches from the trunk. The material should be covered with several 

 shovels of soil. — W . J . Robbins. 



1060. RosT, Clayton O., and Frederick J. Alway. Minnesota glacial soil studies 

 I. A comparison of soils on the late Wisconsin and lowan drifts. Soil Sci. 11: 161-205. PI. 

 1-S, 7 fig. 1921. — A comparison was made of the physical and chemical composition of 3 soil 

 types occurring on 2 adjacent drifts of similar original till but of different geologic age. No 

 distinct differences between the 2 drifts were found in texture, or content of silicon, alumi- 

 num, potassium, sodium, magnesium, non-carbonate lime, nitrogen, or organic carbon. The 

 soils on the older drift are considerably richer in phosphoric acid and contain appreciably 

 more iron and titanium. It would appear that the only distinct influence which the greater 

 age of the lowan drift has been able to exert upon the soils developed upon it is confined to 

 the leaching out of carbonates to a greater depth and an enrichment of the surface layers 

 in phosphoric acid. — W. J. Robbins. 



1061. Stewart, Guy R. The effect of continuous cropping upon the major soil nutrients. 

 Soil Sci. 11 : 321-323. 1921. — Two sets of soils in containers holding ISOO lbs., 1 set very simi- 

 lar and consisting of 6 clay loams, the other dissimilar and consisting of 7 fine sandy loams, 

 have been cropped continuously for G seasons. The average decrease in crop yield amounts 

 to 35.2 per cent for the straw and 34.4 per cent for the grain. In 5 of the 7 sandy loams there 

 has been a reduction of 30 per cent or more of the soluble phosphates while only 2 of the clay 

 loams have begun to show a decrease. Determinations before the soils were planted showed 

 that the fine sandy loams contained 0.05-0.09 per cent, the silty clay 0.13-0.18 per cent of total 

 nitrogen. At the close of 1919 all the soils, both planted and fallow, showed a reduction 

 of 14r-3S per cent of their original total nitrogen content. — W. J. Robbins. 



