122 EXPERIMENT STATION RECORD. [Vol. r., 



soliiblo. Ill tlK! presence i)f a supply of organic matter the sulfofying bucterui 

 appeared to promote the oxidation of the sulpliur and tlie formation ot sul- 

 phuric acid, which in turn acted upon the potash-bearing materials to liberate 

 potassium. 



Pot culture studies with wheat of the fertilizer requirements of four soils 

 showed that for Leonardtown loam the seven pots giving the highest yields 

 were those which received on the average approximately 1 part each of nitrate 

 and muriate to 4 parts of acid phosjihate. For Collington sandy loam the best 

 prt)porlious were 1 part nitrate, 4 parts acid phosphate, and 2 parts muriate. 

 For Norfolk sand the proportions were 2 parts nitrate. 4 parts acid phosphate 

 and 1 part muriate. For Sassafras loam the proportions were 1 part nitrate, 

 3 parts acid phosphate, and 1.7 parts muriate. 



Green manuring experiments to test different methods of handling cinvpeas 

 and soy beans when iised as a fertilizing crop for corn and to compare their 

 value with that of buckwheat as a green manure crop showed that " while no 

 striking increases in yield have been secured, the plats on which the green 

 manuring crop was plowed down in the fall have been consistently better. 

 On the average the increase in yield luts not been sufficient to pay for the 

 seed and for the extra labor involved in handling the green manuring crop." 



Experiments to conTi)are the availability of raw rock phosphate with that of 

 acid phosphate on 23 plats upon which wheat and corn were grown alternately 

 with clover are reported. The phosphates were added in amounts varying from 

 3U0 to 1,500 lbs. per acre. The acid phosphate was markedly superior to the 

 raw rock phosphate on soil in a vei*y low state of fertility and deficient in 

 organic matter. 



Experiments to compare the values of different forms of lime on acid soil 

 showed that raw oj'ster shell gave a slightly greater yield of wheat than the 

 raw limestone, but for the corn the increase was in favor of the limestone. 

 Burned limestone gave a larger yield of wheat but a similler yield of corn. 

 Except for a slight dilference in favor of the burned forms, there seemed to be 

 little room for choice between the materials except in the matter of cost. 



Several studies of the management of the more important soil types of the 

 State and miscellaneous analyses of soil and fertilizer materials are also 

 reported. 



Importance of soil investigations to agriculture, J. Konig {FiUdin(/'s 

 Landw. ZUj., 67 (1018), No. 21-22, pp. 40 4-42 4) .—The author summarizes spe- 

 cial studies on different phases of the physics and chemistry of soils as con- 

 ducted and published by him from time to time. 



On the angle of repose of wet sand, A. G. Webster {Proc. Natl. Acad. /S'c/., 

 5 (I'JIU), No. 7, pp. 26.J-265, fig. 1). — Experiments are reported which showed 

 that when a certain degree of wetne.ss is passed sand acts like a plastic sub- 

 stance, the degree of plasticity and also the limiting slope depending upon 

 the relative amounts of water and sand. For dry sand the angle of repose 

 was found to be about 33°, but as water was gradually added a certain amount 

 of positive cohesion Avas shown, permitting the sand to remain in equilibrium 

 vertically and even to overhang. The limit was reached when the proportion 

 of water to sand was about 1 : 5. Beyond this degree of wetness the angle 

 rapidly decreased. 



Soil survey of Hamilton County, Iowa, K. Espe and L. B. Lindley {U. S. 

 Dcpt. A<jr., Adv. Sheets Field Oper. Bur. Soils, 1917, pp. 30, fig. 1, viap 1).— 

 This survey, made in cooperation with the Iowa ExperinTent Station, deals with 

 the soils of an area of 364,800 acres lying just northwest of the center of Iowa. 

 The county lies just inside the eastward limit of the region covered by the 



