710 EXPEEIMENT STATION RECOKD. 



use of artificial fertilizers. The author is of the opinion that by this method 

 of treatment the fertility of the soils can be maintained until the country is 

 base-leveled. The fact that the old soils of certain parts of Europe are more 

 productive unit for unit than the newer soils of America is referred to as an 

 example of the possibility of maintaining high productiveness on soils densely 

 populated and intensively cultivated. 



In general the author is of the opinion that the facts regarding soil pro- 

 ductiveness " do not offer substantial grounds for an alarming forecast, appli- 

 cable to an industrious and intelligent people willing to be guided either by 

 oriental experience or by western scientific research." 



The relation of certain nonleguminous plants to the nitrate content of 

 soils, T. L. Lyon and J. A. Bizzeli. {Jour. Franklin Inst., Ill {1911), Nos. 1, 

 pp. 1-16; 2, pp. 205-220, dgms. 4). — From the investigations here reported the 

 authors conclude that " the nitrate content of soil under timothy, corn, pota- 

 toes, oats, millet, and soy beans was different for each crop when on the same 

 soil. There was a characteristic relationship between the crop and the nitrate 

 content of the soil at different stages of growth. During the most active grow- 

 ing period of the corn crop, nitrates were higher under corn than in cultivated 

 soil bearing no crop. Under a mixture of corn and millet, nitrates at this 

 period were higher than under millet alone, although the crop yields were 

 about the same on both plats. 



" These phenomena may be accounted for on the assumption that nitrification 

 is stimulated by some processes connected with the active growth and absorb- 

 ing functions of plants, particularly of corn, although there are indications that 

 the corn plant obtains a part of its nitrogen in some form other than nitrates, 

 the combination of which conditions may account for the very high nitrate 

 content of the soil under corn. 



" Under both corn and oats, the nitrate content was higher during the period 

 when the crop was making its greatest draft on the soil nitrogen than in the 

 later stages of growth, in spite of the fact that the nitrates in the uncropped 

 soil were increasing while those in the cropped soil were disappearing. Ni- 

 trates under these crops and under millet failed to increase late in the season, 

 v/hen nitrogen absorption had practically ceased, although uncropped soil 

 showed a very large increase in nitrates at that time. 



"This in conjunction with facts before mentioned, indicates a further in- 

 fluence of the crop on the process of nitrification, and may be accounted for on 

 the supposition that the plants, during their later period of growth, exert, in 

 some manner, a retarding influence on nitrification. 



"The large diiferences in the nitrates under the crops mentioned may, aside 

 from the influence of cultivation, possibly be found in the inherent differences 

 between plants of different species in their stimulating or inhibiting influence 

 on nitrification, as well as in their relative rates and amounts of nitrogen 

 absorption. 



" Changes in the moisture content, or in the temperature of soil under crops 

 during the growing season, had no important effect on the nitrate content of 

 the soil, except under the legume, soy beans. On imcropped soil an increase 

 in moisture content in September was accompanied by a marked increase in 

 nitrates." 



Interpretations of results noted in experiments upon cereal cropping 

 methods after soil sterilization, H. L. Bolley {Science, n. ser., 33 {1911), 

 No. 8Jfl, pp. 229-232). — In this paper, which was read before the American 

 Society of Agronomy at Washington, D. C, in November. 1910, the author takes 

 the position that the beneficial effect of soil sterilization is probably due more 



