SOILS FERTILIZERS. 623 



presence of air. The resulting product is a flue, white, dry powder. The re- 

 actiou is slightly alkaline and the total phosphoric auhydrid is 26.5 per cent. 



A pot experiment with millet comparing ordinaiy superphosphate, pyro- 

 phosphate, and slag showed that the pyrophosphate gave a slightly smaller 

 return in grain than either of the other materials and a considerably larger 

 yield of straw than the slag but slightly smaller than the superi)hosphate. 



The advantages claimed for the new product are that it is better suited to 

 acid soils, the process of manufacture is simpler and cheaper, and it is much 

 less difficult to handle. 



Plant, phosphorite, and soil according to experiments in the Agricultural- 

 Chemical Laboratory of St. Petersburg, P. Kossovicn (Zhur. Opuitn. Agron. 

 (Russ. Jour. Expt. Landw.), 10 {1909), A^o. 6', pp. 782-842, figs. 17).— Pot ex- 

 periments to determine the utilization. of the phosphoric acid of Jura phosphor- 

 ites under varying conditions of soil and plant, extending over a number of 

 years. 1S98 to 1908, are reported in detail. The plants experimented with were 

 mustard, red clover, oats, and flax. Data are given not only for the yield but 

 also for the phosphoric acid content of the seed and straw. 



The oat plant was found to be most resistant to an excess of acidity or 

 alkalinits' in the soil. Flax and red clover were decidedly affected by the 

 reaction of the soil, the first being especially sensitive to alkalinity, the second 

 to acidity. Mustard withstood alkalinity well, but was decidedly affected by 

 acidity. 



\Yith a deficiency of phosphoric acid mustard showed the smallest capacity 

 for utilizing the soil phosphoric acid. A slightly greater capacity in this 

 respect was shown by red clover, but a much higher capacity by oats and flax. 



The behavior of the different plants toward the phosphoric acid of phos- 

 phorite was entirely different from that toward the soil phosphoric acid. In 

 this case the mustard showed the highest assimilative capacity and was able 

 to utilize the phosphoric acid of phosphorite to a considerable extent and with 

 a marked increase in yield. The addition of calcium carbonate to the soil and 

 the absence of acidity reduced the assimilative capacity of mustard to only a 

 slight extent. The largest amount of phosphoric acid was assimilated by the 

 mustai-d from phosphorite in a light sandy acid chernozem soil. Oats and flax 

 utilized the phosphoric acid of phosphorite to a much less extent than mustard. 

 Clover showed a greater assimilative capacity than oats, and the smallest 

 capacity was observed in the case of flax. All of these plants, however, showed 

 marked assimilation of the pTaosphorite only in soils which were decidedly acid. 

 In soils which were not acid or which had been neutralized by the application 

 of lime the assimilation of the phosjjhoric acid of the phosphorite was almost 

 inappreciable. 



The capacity for assimilating difficultly soluble phosphoric acid not only 

 varied with different plants but also with the same plant, depending upon the 

 source of the phosi»horic acid, whether from the soil or from phosphorite. 



The results show in general that the question is complicated by a variety of 

 factors which require further investigation. 



The mining of phosphate with special reference to Florida phosphate, O. 

 Grothe (Technologist, Mitt. Deut. Amer. Tech. Vcrbandes, 15 (1910), No. 1, 

 pp. 1-8). — The extent, character, and methods of mining the phosphate are 

 briefly described. 



The western phosphate lands, M. S. Duffikld (Conservation, 15 (1909), 

 yo. 11, pp. 686-688). — This article refers to the withdrawal from entry by execu- 

 tive order of lauds in Utah, Idaho, and Wyoming supposed to contain phosphate, 



40512— No. 7—10 3 



