March, 1920] SOIL SCIENCE 127 



863. Pickett, B. S. Some soil treatments for mature apple orchards. Illinois Agric. 

 Exp. Sta. Circ. 233. 6 p., fig. 1-8. 1919.— See Bot. Absts. 3, Entry 686. 



864. Singh, T. M. Toxicity of "alkali" salts. Soil Science 6: 463-477. 1918— The 

 effect in soil cultures of sodium chloride, sodium nitrate, sodium carbonate and sodium sulfate, 

 singly and in combinations, as found in field soils by analysis, on the growth of peas and wheat, 

 is reported. The determination of the effect of the above salts on ammonification, nitrifica- 

 tion, and nitrogen fixation in the soil was also made. NaCl was found most toxic followed 

 by NaN0 3 , Na 2 C0 3 and Na 2 SC>4. Stimulation of crop growth and bacterial activities was 

 noted in some cases. — William J. Robbins. 



865. Skinner, J. J., and F. R. Reid. The influence of phosphates on the action of 

 alpha-crotonic acid on plants. Amer. Jour. Bot. 6: 167-180. Fig. 1-9. 1919. 



866. Snyder, R. S., and R. S. Potter. Soluble non-protein nitrogen in the soil. Soil 

 Science 6: 441-44S. 1918. — The object of this paper is to report improvements in a method 

 for determining soluble non-protein nitrogen of the soil and some results obtained with the 

 refined method on the soils used by Stephenson in pot experiments. The soluble non-protein 

 nitrogen was found to consist of nitrates, ammonia and unknown soluble non-protein nitrogen. 

 The unknown was usually decreased by lime but was increased by lime in a sandy loam where 

 casein, albumin, and dried blood were used. — William J. Robbins. 



867. Stephenson, R. E. Effect of organic matter on soil reaction. Soil Science 6: 413- 

 439. 1918. — Using carbohydrate and organic nitrogenous material at the rate of 10 tons per 

 acre and ammonium sulfate at the rate of 1 ton per acre, pot experiments were carried out 

 with a humous acid soil and with a sandy acid soil under lime and no lime conditions. Deter- 

 minations w r ere made of ammonia production, nitrate formation, lime requirement and residual 

 carbonates after 2, 5, 10 and 15 weeks. None of the organic treatments increased the lime 

 requirement of the soils as determined by the Tacke method. The highly nitrogenous mate- 

 rials had the effect of decreasing the acidity especially at the first sampling. The carbohy- 

 drates had a small and inconsistent effect upon the soil reaction and little or no effect upon the 

 carbonates. Ammonium sulfate caused a marked increase in the lime requirement of both 

 soils and exhausted the carbonates. Ammonification was greater in the absence of lime in 

 both soils. Ammonia did not accumulate in the presence of carbohydrates or alfalfa. Nitri- 

 fication occurred more rapidly in the presence of lime. No nitrates were found in the presence 

 of carbohydrates until the 4th sampling. Taking the sum of the nitrogen found as NH 3 and 

 N0 3 there was the greater action in the presence of lime in the untreated soil, but in the 

 absence of lime, in most cases, in the treated soils. — William J. Robbins. 



868. Stuart, William. Commercial potato production in Florida. Potato Mag. I 8 : 

 6-8, 24-25. Fig. 1-9. 1919— See Bot. Absts. 3, Entry 482. 



869. Wallis, E. Pear growing in Victoria. Jour. Dept. Agric. Victoria 17: 76-86* 

 207-216. PI. 16. 1919. — History and evolution of the pear is given, and varieties are dis- 

 cussed. — The relation of pear growing to soil conditions is discussed. The heavy alluvial 

 soil, except that of basaltic nature is suitable for pears. — Kieffer pears planted in deep rich 

 soil have a tendency to promote excessive growth at the expense of fruit. The ideal sub-soil 

 for pears should be of an open texture. Methods of breaking and preparing the soil for plant- 

 ing are discussed. — J. J. Skinner. 



870. Waynick, D. D., and L. T. Sharp. Variability in soils and its significance to 

 past and future soil investigations. II. Variations in nitrogen and carbon in field soils and their 

 relation to the accuracy of field trials. Univ. California Publ. (Agric. Sci.) 4: 121-139. Fig.l. 

 1919. — Determination of the variability in 100 samples drawn at regular intervals in two 

 apparently uniform fields to test the limits of accuracy of sampling. The extreme variations 

 between different samples w-ere of considerable magnitude and show that the results obtained 



