520 EXPERIMENT STATION KIX'ORD. 



No. 3, pp. 289-30.i; ahs. in ('In in. Ah.s., ,i {limit). No. ;!',, pp. .iDlll. .il)D.i) .—The 

 juiflior rt'joc'ts Ixitli (he Kciiiy and llic liuhlort and FicUciidcy nictliods and 

 proposes the followins substitute, which, however, is l)ased upon the liuhlert 

 and Fickendey method : IMace 100 gm.- of the soil in a 1,000 cc. flask with 300 

 cc. of sterilized water and shake for 5 minutes, allowing the larger particles 

 to settle. Then by means of a sterilized pipette connected with a long tube 

 passing through the cork of the flask draw off the turbid liquid to be used in 

 inoculating the culture media. 



Tests of tills method which gave very satisfactory results are reported. The 

 author considers measurements of aerobic and anaerobic assimilation of nitro- 

 gen, nitrification, and denitrification necessary to the determination of the 

 bacterial power of soils. Determinations of putrefactive power and anmioni- 

 fication are considered unnecessary. 



As a culture solution for determining nitrification the author reconmiends 50 

 cc. of the Omelianski solution inoculated with 5 to 10 cc. of the soil solution 

 prepared as described and kept at 30° C. for 10 days. For the study of deui- 

 Iritication the same conditions are recommended except that the period is 

 reduced to 5 days. 



Tillage in its relation to soil moisture, C. C. Thom (Washington 8ta. Popu- 

 lar Bui. 22, pp. Jf). — This is a brief popular discussion based upon the results 

 of one year's study of methods of soil culture best adapted to the conservation 

 of soil moisture in dry farming. These results especially emphasize the impor- 

 tance of plowing or thoroughly disking stubble after harvesting in order to 

 store the winter rains and of disking or otherwise stirring the soil at as early 

 a date in the spring as it will bear cultivation. Decided benefit was also 

 obtained by subsurface packing of the soil immediately or very soon after 

 plowing. 



The scientific reasons for allowing land to lie fallow every other season in 

 regions of deficient rainfall are explained. By this means more moisture will 

 be conserved, if a proper soil mulch is maintained, and a store of available 

 plant food will be accumulated which may be of great service to the succeeding 

 crop. "This is especially true with regard to the supply of nitrates, for the 

 practice of bare fallow is favorable to the growth of nitrifying organisms and 

 consequent increase in available nitrogen." 



The philosophy of conservation of soil moisture is summed up as follows : 

 " Get as much as possible of the winter precipitation into the soil by a system 

 of thorough fall cultivation. Retain it by an equally thorough system of early 

 spring and succeeding summer cultivation." 



On the absorptive power of some Russian soils, A. N. Sabanin (Pochvo'vy- 

 cdyenic [Pedologic], 1908, pp. 87-98; ahs. in Zliur. Opiiitn. Agron. {Russ. Jour. 

 Expt. Landic), 10 (1909), No. 3, pp. 37Jf, 375). — In the experiments here re- 

 ported the absorptive power for ammonia was determined by Knopp's method 

 and that for phosphoric acid and lime by Wolf's method (slightly modified). 



Wide variations were observed in the absorptive capacity of Russian soils of 

 very diverse origin and composition, but there was no parallelism in these 

 variations for ammonia, phosphoric acid, and lime. The greatest absorptive 

 capacity for ammonia was found in soils rich in humus (chernozems), for 

 phosphoric acid in ferruginous (red) soil, and for lime in alkali soils. The 

 absorptive power for ammonia varied on the average with the content of 

 hygroscoi)ic water. Api)arently. absori)tive power is affected to some extent 

 by mechanical composition, but to a less degree than by other factors. The 

 absorption was affected not only by the character but also the quantity of the 

 solution used. 



