1917] SOILS — FERTILIZEES. 521 



particles movina; comparatively slowly are in the pathway of the free ions, 

 and (2) that the change of the structure of the gel at the point of coagulation 

 results in an increase in the adsorptive capacity of colloids. The adsorption of 

 electrolytes by the gel increases with the increase of the electrolyte present for 

 coagulation. The coagulation of the colloidal solutions by means of certain 

 electrolytes can be employed for separation of colloids from crystalloids, pro- 

 vided that only a minimum amount of electrolyte be used for a complete coagula- 

 tion in order to reduce to the minimum the error due to adsorption." 



Facilities for lysimeter and outdoor pot culture work at the station, J. F, 

 BaiuvER {New York State Sta. Tech. Bid. 61 (1911), pp. S-10, pis. 2, figs. S).— 

 The equipment is described and illustrated. 



[Fertilizer experiments], B. S. Emanuel (Svodnyl OtcTiet Steti Kollck- 

 tivnykh Opytov za Trekhafet'ie 1910-191S g. Stavropol, Russia: Stavropol- 

 Kavkas. Selsk. Khoz. Opytn. Sta., 191Jf, pp. 39). — Fertilizer experiments on clay 

 soil intermixed with dark loam at the Stavropol Caucasian experiment station 

 for the years 1910 to 1913, inclusive, are reported. 



It was found that phosphates generally increased the yield of all crops. 

 Superphosphate was more effective on spring cereals than Thomas phosphate, 

 and gave about equal results with potatoes. Sodium nitrate when used alone 

 increased crop yields very little and when added with phosphates seemed to de- 

 crease the influence of the latter on crop yields. Potash frequently increased 

 the yield of potatoes but when used with phosphates it decreased their effect. 

 Phosphates increased the size of potato tubers but did not seem to affect their 

 starch content. Broadcasting of fertilizers followed by deep plowing was ap- 

 parently as effective as row fertilizing. 



The stable-manure business of big cities, C. C. Fletcher (U. S. Depi. Agr. 

 Yearbook 1916, pp. 375-379, pi. 1). — This is a brief description of the process 

 of collection, shipment, grading, storage, and treatment of stable manure from 

 cities in the United States. 



The effect of soil reaction on the availability of ammonium sulphate, R. C. 

 Cook and F. B. Allison {Soil Sci., 3 (1917), No. 5, pp. 487-^98, figs. 2).— Ex- 

 periments conducted at Rutgers College are reported in which sand, silt loam, 

 and sandy loam soils, with respective lime requirements per acre of 3,000, 3,000, 

 and 4,000 lbs., were planted to buckwheat and treated with an excess of 

 potassium and phosphorus and varying amounts of calcium oxid and ammonium 

 sulphate. 



From the standpoint of the utilization of the nitrogen applied it was found 

 that the heavier the soil the less effect calcium oxid has in increasing the avail- 

 ability of ammonium sulphate. Buckwheat seemed to use ammonium sulphate 

 almost as well in the heavier soils in the absence of lime as in its presence. 



It was further found that " small applications of calcium oxid produced prac- 

 tically as large yields of buckwheat as where enough lime was added to neutral- 

 ize all of the acidity or make the soil distinctly alkaline. Buckwheat grown on 

 the more acid soils usually showed a higher percentage of nitrogen but the total 

 yield of the crop was smaller. For this reason the recovery of the nitrogen 

 from the more acid soils in many cases was as great as, or even greater than, 

 that from the alkaline soils. 



" The beneficial effects of calcium oxid on acid soils were much more notice- 

 able on the sandy soils than on the silt loam. The addition of calcium oxid to 

 acid soils allows the soil nitrogen to be made available to such an extent as to 

 supply the needs of the crop. Hence, the use of ammonium sulphate on alkaline 

 soils may produce a smaller increase in yield over checks than where the same 

 amount of the fertilizer is added to an acid soil. 

 16179°— 17— No. 6 3 



