1917] SOILS FERTILIZERS. 427 



containefl total riitrogen 18.62 per cent, of which 17.73 was water-soluble, 

 cyanamid nitrogen 16.75 per cent, nitrogen as dicyandiauiid 0.5 per cent, as 

 ammonia 0.24 per cent, and as "urea" nitrogen (i. e., the element left in the 

 filtrate after precipitation of the dicyandiamid) 0.48 per cent. 



Seven mouths' storage without added water caused no perceptible change. 

 With 5 and 10 gm. of water the changes were very small, the dicyandiamid 

 nitrogen rising to 0.61 and 0.87 per cent, respectively. The presence of 15 gm. 

 of water produced more change, the dicyandiamid nitrogen rising to 1.13 per 

 cent and the urea nitrogen to 0.71 per cent. The cyanamid nitrogen fell to 

 13.61 per cent and the ammonia nitrogen to 0.14 per cent. Very little change 

 took place in the first 10 days when 25 gm. of water was added, but after 

 seven months 2.58 per cent of dicyandiamid was found. With 50 gra. of 

 water profound changes took place and the material set to a hard stone-like 

 mass. After two and one-half and seven months the dicyandiamid nitrogen 

 rose to 7.51 and 9.17 per cent, respectively, the cyanamid nitrogen falling to 

 2.81 and 0.28 per cent, respectively, in the same periods. It is pointed out that 

 calcium cyanamid should not be stored after it has become wet, but may be 

 used immediately. The use of water to produce it in a granulated form is con- 

 sidered not likely to succeed. 



The analyses were performed by Caro's method. 



Calcium cyanamid, L. Malpeaux {Vie Agr. et Rurale, 5 (1915), No. 2, pp. 28- 

 SO). — This is a review of experimental work by the author and others on the 

 use of calcium cyanamid as a fertilizer, showing that when used under proper 

 conditions it gives results comparable with those obtained with sodium nitrate 

 and ammonium sulphate. 



It is concluded that for the practical use of cyanamid it should be applied 

 and incorporated in the soil at the time the soil is prepared for seeding. It 

 should be used in the fall for winter cereals, avoiding spreading when mixing 

 except on pasture. Mixtures of cyanamid with superphosphate should be 

 avoided. 



Two references to literature bearing on the subject are appended. 



Phosphate fertilizers for Hawaiian soils, and their availability, W. T. 

 McGeoege {Hatvaii Sta. Bui. 41 {1916), pp. 45, pls. 4)- — Studies of the solubility 

 of the phosphoric acid naturally occurring in certain Hawaiian soils, as well 

 as of the behavior of various phosphates when applied to them, are reported. 



Pot experiments with millet, ccwpeas, buckwheat, radishes, and turnips on 

 sandy volcanic soil, ferruginous red-clay soil, and a red soil with less clay, to 

 determine the availability of different phosphates when applied in amounts 

 equivalent to 0.007, 0.014, 0.021, and 0.028 per cent phosphoric acid, indicated 

 that the soluble phosphates in frequent light applications are the most effective 

 on Hawaiian soils, especially the red clays. Iron and aluminum phosphates 

 were found to be readily available sources of phosphoric acid in Hawaiian 

 soils, the former more so in the first crop in the absence of added lime. In sand 

 cultures these phosphates surpassed clay and rock phosphate. 



" In most locations it is poor economy to add bone meal or other difficultly 

 soluble phosphates to Hawaiian soils. ... In wet districts (uplands) phos- 

 phate rock, bone meal, basic slag, or reverted phosphate should be very effective, 

 more especially so if applied to highly organic soils or used in systems of di- 

 versified agriculture where they may be incorporated with green manure crops." 

 Basic slag was more effective as a source of phosphoric acid than phosphate 

 rock, bone meal, or reverted phosphate. Lime applied with phosphates tempo- 

 rarily assisted the plants in assimilating phosphoric acid, but it soon lost its 

 effectiveness unless present in excessive amounts. 



