NOTES AND ABSTRACTS, 
205 
The general trend of the evidence proves that plants can make use of many 
of the organic compounds direct, and that such compounds are able to replace 
nitrates as plant foods. 
Certain of the organic compounds, notably guanidine and solanine, have 
decidedly harmful effects on plant life. 
The value of this work to soil investigators and students is great, for a know- 
ledge of the beneficial and harmful compounds is of very great importance, and 
may prove to be the first step towards the solving of many now obscure problems. 
C. P. C. 
Soil Protozoa, Activity of. By G. P. Koch {Jour. Agr. Res. v. pp. 477-488, 
Dec. 1915). — Many encysted protozoa exist in soils, but it is only when in the 
active condition that they can destroy bacteria. The author concludes that 
under ordinary greenhouse conditions small protozoa of various types are active 
in some soils, but their presence is limited ; that active protozoa do not appear 
to be present in field soils, and therefore cannot limit the number of bacteria ; 
they are present in the encysted form and may become active when standing 
water accumulates, moisture being the principal influencing factor, organic 
matter, temperature, and the physical properties of the soil being secondary ones. 
One or two hours are sufficient to wake the small protozoa to an active from 
an encysted condition, while forty hours may be required by larger forms. 
F.J.C. 
Soil Sterilization, Partial, by Antiseptics. By W. Buddin (Jour. Agr. Set. 
vi. pp. 417-451, Dec. 1914). — Treatment of soil by means of antiseptics is 
followed by an initial decrease in numbers of bacteria, followed by a large sus- 
tained rise ; protozoa and nitrifying organisms are killed ; an initial increase 
in ammonia content followed by a considerable rise, and in productiveness of 
the soil. No increase in the dose causes any change in the results when once 
partial sterilization is effected. True partial sterilization has been obtained 
only with easily volatile and removable antiseptics, while substances not com- 
pletely removable have a lasting influence on the micro-flora. Benzene, toluene, 
phenol, cresol, cyclohexane, pentane, hexane, heptane, chloroform, ether, 
acetone, formaldehyde brought about partial sterilization. These have proved 
to increase the productive capacity of the soil in pot cultivations, but are unsuit- 
able for application on a larger scale. — F. J. C. 
Soils, Effect of Heat on Hawaiian. By W. P. Kelley and W. McGeorge 
(U.S.A. Exp. Stn., Hawaii, Bull. 30, Dec.i 913). — Heating to ioo°C. was found 
in nearly all cases to bring about an increase in the water-soluble mineral con- 
stituents of the soil, with the exception of iron, also an increase in ammonifica- 
tion. Much the same results were observed at 2oo°C, but there was a loss of 
25 per cent, of the total nitrogen content. 
Treating the soil with a temperature of 25o°C. showed the same effects, but 
much intensified. Igniting the soils, however, decreased the solubility of the 
lime and magnesia. 
Treatment at 200 0 C. stimulated ammonification in the field, but caused cessa- 
tion of nitrification for two months. — C. P. C. 
Strawberry 4 Amanda.' By U. P. Hedrick (U.S.A . Exp. Stn., Geneva, Bull. 403), 
— A mid-season fruit of promise, standing the rough usages of market transport. 
Originated in Ohio in 1904. — E. A, Bd. 
Strawberry-growing. By J. G. Moore (U.S.A. Exp. Stn., Wisconsin, Bull. 
248, March 1915; figs.). — Detailed instructions on the whole art and craft of 
strawberry -growing as practised in Wisconsin. — M. L. H. 
Strawberry-garieties. By-O. M. Taylor (U.S.A. Exp. Stn., Geneva, Bull. 401, 
28 pp.). — A useful report of a trial of a large number of varieties tested at the 
Geneva Station. Varieties are first grouped as to different characters, such 
as season of flower, vigour of plant, susceptibility to disease &c, and are 
afterwards described in full botanical detail with historical notes* Few European 
varieties are recorded. — E. A. Bd. 
Sunflower Growing for Seed. (Queensland Agr. Jour. April 1915, p. 137.) — 
Tall mammoth Russian sunflower yields 50 bushels of seed from an acre, the head 
being 15 inches in diameter and bearing 2,000 seeds ; 4 to 6 lb. of seed are sown 
to the acre, in drills 5 feet apart ; the seed is dibbled at intervals of 3 feet ; the 
plants may be thinned afterwards to ensure full exposure to the sun 4 When the 
plants are 12 inches high a slight earthing up is beneficial* 
