324 EXPERIMENT STATION RECORD. [Vol.43 



normal and war times. I'art 2 describes the commercial aspects of nitrogen 

 resources, including natural by-pi'oduct and fixation compounds and the rect'iit 

 developments and changes In the nitrogen industry practice. Part 3 is a 

 review of the economic nitrogen industry outlook. A bibliography of recent 

 literature on the nitrogen industry is included. 



Plant ashes as a source of potash (Bill. Imp. Inst. [L07idon], 11 {1910), ^o. 

 3, pp. 281-289). — Analyses of aslies of white chestnut, black wattle, and olive 

 wood from East Africa indicate that the crude wood ashes "would form 

 valuable manures for use in East Africa on account of the high percentage of 

 potash, lime, and phosphoric acid which they contain. Owing to the high 

 temperature at which the ashes were produced, they contain a considerable 

 quantity of caustic lime which Is of far more value for addition to the soil than 

 calcium carbonate. . . . The olive-wood ash probably does not contain enough 

 potash to be remuneratively extracted." 



Analyses of blue gum-tree ash from Tasmania indicate its manurial vahio 

 on account of its content of soluble potash salts and the lime and phosphoric 

 acid contents of its insoluble constituents. The sodium carbonate content was 

 i-Mtlier high. The percentage of water-soluble potash was higher than in 

 most plant ashes from mature woods. 



Analyses of dry leaves, wood, and ashes from the African tragacantli showed 

 that the wood and bark ash contains a greater percentage of soluble potasli 

 than the ash from the leaves. " The wood and bark of the African tragacanth 

 evidently form a more valuable source of water-soluble potash than the leaves, 

 but both materials compare favorably with the majority of plant products 

 used as sources of potash." 



Analyses of sunflower aslies are also discussed. 



Basic slag v. acid phosphate, C. E. Thokne {Mo. Bui. Ohio Sta., 5 {1920), 

 No. 3, pp. 91-93). — Experiments on silt loam and clay soils conducted since 1900 

 to compare basic slag with acid phosphate are reported. 



On unlimed soil deficient in lime it was found that 1 ton of 17 per cent basic 

 slag, containing 340 lbs. of phosphoric acid, increased crop yields by an amount 

 not quite $3 more than 1 ton of 14 per cent acid phosphate, containing 280 lbs. 

 of available phosphoric acid, showing that a pound of phosphoric acid was less 

 effective in basic slag than in acid phosphate. On the limed land in both cases 

 a pound of phosphoric acid gave a larger gain in acid phosphate than in basic 

 slag, Irnt a ton of basic slag, with its 60 lbs. more phosphoric acid, produced 

 $2..54 more increase on clay soil than a ton of acid phosphate. 



" Tlie results do not justify the purchase of basic slag in preference to, acid 

 phosphate for use on average land, when the pound of total phosphoric acid in 

 basic slag, limed included, costs more than the pound of available phosphoric 

 acid in acid phosphate." 



Basic slag v. acid phosphate, C. E. Thobne {Mo. Bui. Ohio Sta., 5 {1920), 

 No. Jf, pp. lJil-lJ/6). — This is a revision of the above report in which additional 

 data bearing on the subject are included to strengthen the conclusions. 



Sulphur in plants and soils, A. M. Peter {Kentucky Sta. Rpt. 1918. pt. 1, 

 pp. 38, 39). — Experiments on the composting of sulphur with soil, phosphate 

 rock, and manure, using soil from the station farm, showed that nearly three- 

 fourths of the phosphate added or already present in the soil was finally ren- 

 dered soluble in ammonium citrate solution, although the action was slow in 

 beginning and did not progress properly until after the addition of sulfofying 

 organisms. These experiments are considered to indicate the practicability of 

 this method for producing acid phosphate on the farm. Laboratory experiments 

 with eight Kentucky soils of different types showed that sulphur added at the 



