No. 1, AiTousT, 1921] SOIL SCIENCE 85 



nous substances without the aid of bacteria. Nitrites act on ammonia with the liberation of 

 nitrogen; this action is increased when certain substances like aniline dyes, especially mala- 

 chite green, fluorescin, or methyl red are present, while it is retarded, and even inhibited, 

 in the presence of colloidal substances. Since well water contains quite a number of organic 

 substances, which act as protective colloids, the simultaneous presence of ammonia and 

 nitrites can be explained. Sterile soil acts like colloids. Some loss of nitrogen may occur in 

 manure, but this loss in only a very slight one. — H. Engelhardt. 



652. Sen, J. Report of the Imperial Agricultural Chemist. Sci. Rept. Agric. Res. Inst. 

 Pusa 191Q-20: 31-45. 1920. — An examination of soils of the Pusa farm to determine the effect 

 of various fertilizers alone and in combination on permanent soil fertility leads to the conclu- 

 sion that "the outstanding feature is the value of a combination of green manure and super- 

 phosphate." — Experimental evidence shows that superphosphate is held in calcareous soils 

 by chemical combination, and, since the reaction goes on rapidly, the phosphate is restricted 

 to surface layers of the soil. It is held in noncalcareous soils by adsorption, hence is widely 

 and uniformly distributed through such soil, and is more available for use by the roots of grow- 

 ing plants. "The distribution of the phosphoric acid of those soluble phosphates which are 

 without action on calcium carbonate, through a column of soil is of a uniform type even in 

 highly calcareous soils, and the phosphoric acid penetrates to a considerable depth," suggest- 

 ing that "such phosphates would be more efficacious than superphosphates in calcareous 

 soils." — Under laboratory conditions, pieces of sugarcane with the cut ends sealed with 

 paraffin, and kept in desiccators, showed slight increase in sucrose content; subsequent wet- 

 t ing causes a fall in sucrose content; these sucrose transformations are similar to those observed 

 in cane windrowed under field conditions and are believed to be closely connected with enzy- 

 matic activity. — Repetition of water culture experiments indicates that poor results from cul- 

 tures previously reported (Pusa Memoir Vol. II, No. 3, Botanical Series) were due to excessive 

 concentration of the nutrient solutions, and not to the excretion of specific toxic substances 

 by the roots. — Periodic analysis of the soil air in a mixed orchard showed the largest CO2 

 content in a grassed plot, an intermediate amount in a grassed plot aerated by means of 

 trenches, and least in a plot under surface cultivation. The percentage of CO2 attains a 

 maximum during the summer monsoon. — In manurial experiments with rice, ammonium sul- 

 phate along with phosphates gave increasing yields up to 160 pounds per acre, after which 

 there was a decrease, till with 320 pounds per acre the yield was little better than with no 

 nitrogen at all. Smaller applications of nitrogen increased the proportion of straw to grain; 

 80-160 pounds per acre gave maximum proportion of grain, and is therefore the most economi- 

 cal application. Green manure alone increased the crop up to 65 per cent, but in combination 

 with ammonium sulphate had little effect. Ammonium sulphate produced an increase in 

 the amount of nitrogen in the grain almost proportional to the amount of sulphate added as 

 fertilizer. — W infield Dudgeon. 



553. Shedd, O. M. A short test for easily soluble phosphate in soil. Soil Sci. 11: 111- 

 122. 1921. — A test requiring less than 1 hour to complete is described for testing for easily 

 soluble phosphate in soils. The relative amounts of precipitates are taken to indicate the need 

 of the soil for phosphorous.— IT. J. Robhins. 



5.54. Stead, Arthur. The agriculture and soils of the Cape Province, IV and V. Witkop- 

 Burghersdorp. Jour. Dept. Agric. Union of South Africa 1: 660-670, 819-S28. 1920.— Soils 

 from a number of farms in the province were analyzed chemically *and mechanically; their 

 fertility is discussed. — J . J. Skinner. 



555. ToTTiNGHAM, W. E., AND E. B. Hart. Sulfur and sulfur composts in relation to 

 plant nutrition. Soil Sci. 11: 49-73. PL I-4, fig. 1-2. 1921.— The changes in acidity, citrate- 

 soluble and water-soluble phosphate, bacterial numbers, and the effects on crop yields of 

 composts of soil or manure with sulphur or with sulphur and horse manure showed appreciable 

 increase in acidity but no increase in citrate-soluble phosphate after 15 weeks. Sulphur 



