20 EXPERIMENT STATION RECORD. 



unit of fixed uitrogen produced; (4) the great ecouoiuy in the consumption of 

 organic materials in the soil by nitrogen fixers is to be explained by their symbi- 

 osis with autotropic organisms, which, growing in darlvuess, form organic com- 

 pounds through the decomposition of carbon dioxid. accompanied by the libera- 

 tion of oxygen. 



The natural solution of the nitrog-en question by soil inoculation in sug'ar 

 beet culture, J. Stoklasa {Bl. Zackerriibenhau, 17 (IDIO), Nos. 1, pp. 1-5; 2, 

 pp. 2.'t-29). — Inoculation experiments with cultures of Azotobacter and Radio- 

 bacter on soils planted to beets are rejjorted. showing decided increases in yield 

 following inoculation. The author concludes from his results that important 

 increases in yield from a practical standpoint may be secured by such inocula- 

 tion if the soil contains a sufficient supply of suitable carbohydrate food. lime, 

 phosphoric acid, and potash, and is well aerated by proper cultivation. 



The cooperation of micro-org'anisms in the utilization of insoluble phos- 

 phates of the soil with higher plants, S. de Grazia {Arclt. Fanintcol. IS per. c 

 »sci. Aff., 8 {1909), pp. JjSe-Jf'jO ; Staz. Sper. Agr. Ital., 43 {1910). No. 2, pp. 

 n9-lS.'i; nbs. in Chem. Zenthl., 1910, I, No. Jf, pp. 29.'i, 295).— This article deals 

 with studies of various factors affecting the solubility of the phosphates of 

 soils in acids produced by bacterial activity. 



It was found that the addition of chloroform reduced bacterial activity and 

 decreased the acidity produced, but at the same time increased the solution 

 of phosphates. This is ascribed to incre:ised enzym action resulting in the 

 hydrolization of the tricalcium phosphate of the culture medium, producing 

 dicalcium and monocalcium i)hosphate and calcium hydroxid, which neutralized 

 the acidity of the culture. 



Soils of Mississippi, W. L. Hutchinson {Mississippi Sta. Bui. 132, pp. 8, 

 figs. 2). — This bulletin explains how the fertility of soils may be maintained 

 by proper drainage, good tillage, prevention of surface erosion, and maintenance 

 of an adequate supply of humus in the soil. 



Soil experiments on the upland loam of southeast Missouri, M. F. Miller 

 and C. B. Hutchison (Missouri Sta. Bill. 83, pp. 16, figs. 3). — The soil on which 

 these experiments were made was located on the typical rolling upland of the 

 Hillsboro group of soils. " The soil is partly of limestone and partly of sand- 

 stone origin, free of gravel and of a very fine sandy or silty nature underlaid by 

 yellowish clay loam. The soil on this particular field had been cropped for a 

 number of years and was badly run down." 



The experiments were made on 3 series of 5 fifth-acre plats each. The fer- 

 tilizer treatment consisted of cowpeas; cowpeas and lime: cowpeas. lime, and 

 phosphorus; and cowpeas. lime, phosphorus, and potassium. The rotation of 

 crops was corn, cowpeas, wheat, and clover, the cropping of the series of plats 

 being so arranged that one series was in corn, one in wheat and one in clover 

 each year. 



The experiments showed that the soil was lacking, first, in humus and nitro- 

 gen, and second, in phosphorus, but only slightly deficient in potash and lime. 

 There was a striking response to the application of phosphates, especially in 

 the case of clover. The application of lime and of potash and the growing of 

 cowpeas also gave some return. 



Specific recommendations for the handling of this soil to increase its pro- 

 ductiveness are given. 



Soil experiments on the prairie silt loam of southwest Missouri, M. F. 

 Miller and C. B. Hutchison {Missouri Sta. Bui. S-'f. pp. 19-35. figs. 5). — The 

 soil on which these experiments were made was a dark gray loam to a depth of 

 8 in., underlaid by a silty clay to depths varying from 2 to 3 ft. On account 

 of the fine texture of the soil and the level topography of the country drainage 

 w^as poor in many cases. 



