724 EXPERIMENT STATION RECOED. 



It is stated that in a " study of reactions between farm manure and reen- 

 forcins substances, such as feldspar, rock phosphate, and peat, investigation 

 of fermenting manures has shown in all cases decrease of water-soluble phos- 

 phorus. Fermenting mixtures of manure and rock phosphate have shown 

 greater decreases than manure alone. A typical experiment with mixed cow 

 and horse manure fermented G months without and with rock phosphate (25 

 lbs. fresh manure and i lb. rock jihosiihate) involved 10.45 gm. soluble phos- 

 phorus in the manure and 18.49 gm. in the phosphate mixture at the start. 

 The water-soluble phosphorus of the manure decreased from 86.7 per cent to 

 65.6 per cent of the total, a decrease of 24.3 per cent of the original water- 

 soluble phosphorus. The sample with phosphate gave a decrease from 34.3 

 per cent to 14.7 per cent of the total phosphorus, a loss of 57 per cent of the 

 water-soluble phosphorus. Common solvents for inorganic phosphates, such 

 as carbonatcxl water, ammonium citrate solution, and fifth-normal nitric acid 

 recovered the depressed phosphorus only partially. 



" Two and one-half months' standing with and without antiseptics produced 

 the following changes of water-soluble phosphorus in manure-rock-phosphate 

 mixture : Normal fermentation, decrease from 33.26 to 17.64 per cent of total ; 

 saturated with chloroform, decrease from 32.61 to 28.11 per cent; saturated 

 with formaldehyde, decrease from 29.36 to 26.85 per cent. The losses amounted 

 to 47, 13.8, and 8.5 per cent, respectively, of the water-soluble phosphorus. 

 The results seemed to indicate that the losses observed were not due primarily 

 to ' reversion ' of inorganic phosphates, but chiefly to bacterial activity. 



" Manure bacteria grown on media prepared from extract of fresh manure- 

 rock-phosphate mixture reduced the soluble phosphorus of the media 23.8 to 

 63.6 per cent. Fresh intact bacterial cells of specific organisms and manure 

 flora contained 34 to 53 per cent of their phosphorus in water-soluble form. 

 Drying in vacuo at room temperatures did not alter the solubility of the phos- 

 phorus appreciably. The residual phosphorus was partly recovered from 

 crushed cells by water and did not appear especially resistant to 0.2 per cent 

 acid or alkali solvents. These results aiipear to point conclusively to bacteria 

 as the chief cause of loss of soluble phosphorus in fermenting manures. 



" Further work is in progress with acid phosphate and involving also the 

 roles of soil organisms and the plant in rendering phosphorus of manure 

 bacteria available to crops." 



The sprinkling of manure, M. Ringelmann {Jour. Agr. Prat., n. scr., 23 

 {1912), No. 6, pp. 179-182, figs. -//). — Various methods and devices for sprinkling 

 manure to prevent harmful fermentation are described. 



Fertilizer chemistry: A report of progress, P. Rudnick {Ahs. in Science, 

 n. scr., 35 {1912), No. 898, pp. J,25, ^26).— This is an abstract of a paper read at 

 the Washington meeting of the American Chemical Society in 1911, in which 

 some of the more important developments in the fertilizer industry are re- 

 viewed, including the increase in consumption of commercial fertilizers, advance 

 in cost of materials supplying nitrogen, growth in the demand for nitrogenous 

 materials of higher availability, the proposal to use raw rock phosphate in place 

 of superphosphate, the effect of the German potash controversy in stimulating 

 the search for new sources of commercial potash in the United States, and the 

 need of a comprehensive and scientifically accurate theory of fertilizers. 



The rational use of commercial fertilizers, A. M. Soxjle {Bui. Univ. Ga., 

 1911. No. 172, pp. 2!i, figs. 8). — The general principles underlying the use of fer- 

 tilizers are discussed with especial reference to their employment in a perma- 

 nent system of agriculture adapted to Georgia conditions. 



It is stated " that when used with any degree of skill, fertilizers are a profit- 

 able investment " for Georgia farmers, but it must be borne in mind in using 



