342 EXPERIMENT STATION RECORD. 



experiments in 1904 were designed especially to further investigate this point. Dif- 

 ferent series of plats were irrigated after the wheat began to head, once a week, once 

 in 2 weeks, and once in 3 weeks. A record of the amounts of water applied* mete- 

 orological conditions of the season; the relations between the amount of water 

 applied, soil moisture, and yield; and the movement of the water in the soil is given. 

 Owing to unfavorable meteorological conditions the yield of wheat was only about 

 one-third of that of the previous season. 



It was found that irrigating oftener than once in 3 weeks after the wheat began to 

 head increased the yield, but scarcely enough to pay for the additional irrigations. 

 " Twenty-four in. of water gave the greatest yield per inch of water applied, and 

 while 35 and 29 in. of water gave greater yields than did 24 in., the increase per inch 

 of water is very small. Twenty-four in. was the most economical amount. 5 ' The 

 conclusion is reached that 25 per cent is the optimum amount of water in this soil 

 for the production of wheat and beyond this the wheat is very sensitive to an increase 

 in the moisture content of the soil. 



While variations in texture and the irregular distribution of the water through the 

 soil made it difficult to obtain results accurately expressing the true moisture condi- 

 tions of the soil, the indications are that " the plats as a rule did not gain materially 

 in moisture below the second foot during the season and there were indications of a 

 general loss in total moisture toward the end of the season. There was no indication 

 of an appreciable loss of moisture from the percolation into the soil below the limits 

 of the roots of the wheat." 



Soil temperatures 1903-4, G. A. Crosthwait (Idaho Sta. Bid. 49, pp. 3-6). — 

 Tabular summaries of weekly observations at Moscow on soil temperatures during 2 

 years at 10 different depths varying from 1 in. to 6 ft. 



Diffusion in acid and neutral media, particularly in humus soils, H. 

 Minssen ( Landw. Vers. Stat., 62 (1905), Xo. 6, pp. 445-476).— The literature of the 

 subject is reviewed, especially the investigations of Blanck (E. S. R., 14, p. 848), and 

 investigations by the author on diffusion are reported. 



The results lead to the conclusion that Blanck' s method is so defective and his 

 results so unreliable that his conclusion that diffusion of water in acid soils is hin- 

 dered by the presence of humus acids is not warranted. The author concludes that 

 neither humus aeids nor any other organic or mineral acids in dilute solutions inter- 

 fere with the diffusion of water or salt solutions. The "physiological dryness" of 

 moor soils can not, therefore, be ascribed to humus acids. 



Experiments in fertilizing- chernozem, V. V. Wiener (Rhozyain, 1904, Feb., 

 Sup.; abs. in Zhur. Opuitn. Agron. (Russ. Jour. Expt. Landw.), 6 (1905), Xo. 1, pp. 

 48-50) . — The article contains the main results of 5 years' work at the Shatilov Exper- 

 iment Station (Government of Tula) on the question of fertilizing ehernozem. 



The results are in the main of local and limited interest. A close direct connection 

 was observed between the action of the fertilizers and the meteorological conditions 

 in the sense that higher effects of the mineral fertilizers were observed in years of 

 abundant yields with favorable meteorological conditions, when, according to a gen- 

 erally accepted opinion, chernozem has no need of fertilizers for the production of 

 large crops. Deep and shallow plowing were equally favorable. The author con- 

 eludes that the reputation of chernozem for great fertility is unmerited and that the 

 use of fertilizers, especially phosphates, is very profitable. — p. fireman. 



Soil bacteriological studies, J. G. Lipman ( New Jcrxey Stas. Rpt. 1904, pp. 237- 

 289, pis. 6). — The importance of the biological processes in the soil is discussed, and 

 studies of the physiology and morphology of members of the Azotobacter group, 

 including three members — Azotobacter vinetandii, A. beyerincH, and A. ivoodstoinui — 

 discovered by the author, are reported. 



The relative nitrogen-fixing power of these organisms, as well as of A. chroococcinn 

 and several smaller bacilli, designated Bacillus 30a, B. 33, B. 34, and B. 35, which 



