NOTES AND ABSTRACTS. 



161 



Snails and Mealy Bug, Protection from (Queensland Agr. Jour. May 191 8, 

 p. 186). — For Snails : Sprinkle powdered alum round their haunts and also 

 round plants or beds of plants to be protected : if this is persisted in for a few 

 nights a marked difference will be found. Alum does not appear to hurt vegeta- 

 tion. For Mealy Bug : Sprinkle the soil of the pots with naphthalene and just 

 turn it in, say, half a teaspoonful to a 6-inch pot ; a little may also be sprinkled 

 on the crown of the plant. In some cases this is a deterrent more than an 

 exterminator. — C. H. H. 



Soil Acidity as influenced by Green Manuring. By J. W. White (Jour. Agr. 

 Res. vol. xiii. No. 3, April 191 8 ; pp. 1 71-197). — The author finds that in general 

 when fresh green manures are ploughed in, on acid silty loam soil, there is a 

 reduction of the acidity, but this is followed by increased soil acidity ; nitrifica- 

 tion can go on quite satisfactorily under suitable moisture, temperature, and 

 aeration conditions ; and that green manured soils are rich in nitrates, in spite 

 of the soil acidity. The actual cause of the increased acidity was due to the added 

 organic matter or the fermentation changes which have occurred in their residues, 

 and not due to the nitrification which had taken place. — A . B. 



Soil Bacteria, Influence of Carbonates on. By H. L. Fulmer (Jour. Agr. 

 Res. xii. Feb. 19 18, pp. 463-504). — Experiments were made with a number 

 of soils from Wisconsin to determine the influence of carbonates of magnesium, 

 of calcium, and limestone upon the number of bacteria normally present in these 

 soils. The author finds that the number of bacteria is increased by the applica- 

 tion of these carbonates in acid loams and sands. Magnesium carbonates in- 

 crease the number to a much greater extent than either limestone or calcium 

 carbonate. Nitrification is increased by treatment of these soils with the three 

 carbonates. Magnesium carbonate in soil to which no nitrogenous substance 

 was added favours nitrate accumulation more than does either calcium carbonate 

 or limestone. Bacterial cultures of B. tumescens and B. subtilis ammonify blood- 

 meal better when sterile soil is treated with any of these carbonates. 



Pure cultures of B. radicicola also showed increases when placed in sterile 

 soil treated with magnesium or calcium carbonates. In acid or neutral soils 

 treated with magnesium carbonate until soils become alkaline, it was found that 

 B. azotobacter is greatly increased in number compared with that of untreated 

 soil. Small quantities of the carbonates were better than larger quantities in 

 producing these effects. — A. B. 



Soil Extracts. Water Extractions of Soils as Criteria of their Crap-producing 

 Power. By J. S. Budd. Effect of Season and Crop Growth in Modifying th3 

 Soil Extract. By G. R. Stewart. The Freezing-Point Method as an Index of 

 Variations in the Soil Solution due to Season and Crop Growth. By D. R. 



Hoagland (Jour. Agr. Res. xii. pp. 297-395, Feb. 19 18). — These three papers 

 give accounts of part of the recent investigations into the actual composition 

 of the solution of earth salts as it exists in the soil around the soil particles. 

 They are too lengthy and full of detail to abstract fully, but it seems probable 

 that, along lines such as are indicated, a method of estimating soil fertility more 

 reliable than present methods of chemical analysis of soils may be developed. 



F. J. C. 



Soil Fertility, Measurements of. By W. H. Jordan (U.S.A. Exp. Stn., New 

 York, Bull. 424, Aug. 19 16, pp. 389-412 ; 17 tables). — Describes experiments 

 (during two years in a forcing house) with nine unlike soils from different parts 

 of the State for the purpose of studying the relation of various methods of 

 chemical examination to their crop-producing capacity. The methods were : 



(a) Complete analysis. 



(b) Determination of material soluble in hydrochloric acid sp. gr. 1*115 by 

 the A.O.A.C. method. 



(c) Determination of materials rendered soluble by continued leaching for 

 ten days with (1) water, (2) N/200 HC1, (3) N/25 HC1. 



(d) Determination of soluble material obtained by shaking five hours with 

 (1) water, (2) N/200 HC1, (3) N/25 HC1. 



By none of these methods was there established any relation between the 

 amounts of nitrogen, phosphoric acid and potash, either total or soluble, and 

 crop-producing capacity. 



There appeared to be some relation between the total soluble matter in the 

 soil and productiveness, to the extent that two soils giving a very low yield of 

 barley showed greatly less solubility than did the others. This relation, how- 

 ever, was not consistent throughout. 



The general result shows that we are not yet in a position to measure the 

 fertility of the soil by any method of chemical examination. — F t G. A. 



