534 



NATURE 



[January 22, 1920 



is calculated to amount to 39 per cent, of the 

 world's supplies bi combined nitrogen, Chile 

 nitrate accounting for about 41 per cent. War 

 developments are now challenging- the supremacy 

 of the Chilean industry. The market price of the 

 synthetic products, and of ammonium sulphate, 

 bids fair to govern that of ChHe nitrate instead 

 of following it as hitherto. The Committee esti- 

 ■utes that the post-war supply of fixed nitrogen 

 potentially available is likely to show an increase 

 of from 30 to 40 per cent, upon the pre-war pro- 

 duction, or to be of the order of a million metric 

 tons per annum. It is, however, of opinion 

 that this amount is not greater than would have 

 been the case under normal conditions, to judge 

 from the pre-war rate of growth in consumption. 

 But it is significant that this increase is almost 

 wholly due to the development of synthetic pro- 

 cesses. There would seem to be no fear that 

 over-production will be a serious factor in the 

 post-war situation. 



As regards the uses of nitrogen products prior 

 to the war, at least 70 per cent, of the world's 

 total supplies of nitrate and ammonia nitrogen 

 was utilised in agriculture. vOv.ing to their com- 

 paratively limited employment in this country, and 

 the somewhat conflict ing experience of our experi- 

 ment stations, which, as the evidence presented 

 to the Committee shows, have scarcely given 

 sufficient study to the question, there is no abso- 

 lute proof, as yet, that synthetic fertilisers are 

 wholly suited to the particular circumstances of 

 this country. The Committee, however, has no 

 doubt as to their utility, and specifically makes 

 mention of the value of nitrate of lime, as now 

 manufactured, and of calcium cyanamide when 

 free from dicyanodiamide, in which opinion it 

 would seem to be supported by the Board of Agri- 

 culture. 



Dr. E. J. Russell, of the Rothamsted Experi- 

 mental Station, in a recent paper published in 

 the Journal of the Society of Chemical Industry, 

 states that the results of all published field trials 

 show that the three fertilisers— nitrate of soda, 

 sulphate of ammonia, and cyanamide — when com- 

 pared on the basis of equal nitrogen content have 

 the following values: - 



Nitric nitrogen ... ... 100 



Ammoniacal nitrogen ... ... 07 



Cyanamide nitrogen ... ... go 



But, he adds, these include cases where the \ 

 cyanamide nitrogen could have had no proper 

 chance of acting. Cyanamide, he points out, pre- 

 sents the characteristic that it is not at ' once 

 available for plants, but has to undergo change in 

 the soil whereby ammonia is formed, which 

 afterwards nitrifies. The whole value of the 

 material, therefore, depends on the rate at which 

 l*e change proceeds. In some soils it goes on 

 rapidly, and here cyanamide is very effective. In 

 others, however, it proceeds more slowly. The 

 production of the ammonin would appear to take 

 place in two stages, the first being purely 

 chemical, and the second bacterial; further, the 

 NO. 2621, VOL. 104] 



agent producing the chemical change is not always 

 present in sufficient quantity in the soil. Under 

 j better advice, such as is now obtainable, the 

 j farmer could be warned beforehand, and the use 

 I of cyanamide kept to those numerous cases where 

 ', it can decompose rapidly and act well. In these 

 j circumstances the value of cyanamide nitrogen 

 might rise well above 90, and, what is more 

 important, the risk of failure might be consider- 

 ably reduced. 



Of course, the war made imperative calls upon 

 the nitrogen industries, and these, notwithstand- 

 ing their expansion, were quite unable to cope 

 with the demands for both explosives and fer- 

 tilisers. The needs of agriculture were conse- 

 quently largelv set aside, to the g-reat detriment 

 of the world's food supply. The effect has been 

 the almost universal recogni!ic« of the vital im- 

 portance of nitrogenous fertilisers. The difficulties 

 of obtaining them and the consequences which 

 have followed from the shortage have together 

 furnished an object-lesson which the world will 

 not soon forget. The Committee learns that the 

 visible demand for nitrogenous fertilisers is ever} - 

 where considerably in excess of the pre-war con- 

 sumption. 



With respect to the relative costs of synthetic 

 and non-synthetic processes, the Committee con- 

 cludes that under favourable conditions in regard 

 to the cost of power and of raw materials, the 

 nitrogen fixation and allied processes, speaking 

 broadly, stand at a very considerable advantage 

 as compared with non-synthetic methods. It ought 

 to be stated, however, that all its estimates are 

 based upon pre-war" prices and factory costs, and 

 it by no means follows that the price of coal and 

 of water-power will advance pari passu. A water- 

 fall does not "down tools " like a miner, nor does 

 it attend football matches and go on strike for 

 any or no cause in particular. But still, fallible 

 as the basis may possibly be under present or 

 prospective conditions, the comparison of costs is 

 instructive and significant. The average market 

 price of a metric ton of combined nitrogen in the 

 United Kingdom during 1911-13 was 6yl. and 66/. 

 in the forms of Chile nitrate ar.d ammonium 

 sulphate respectively. The synthetic processes can 

 produce a metric ton of available combined nitro- 

 iren at a cost, at the factory, of from 20/. to 30Z. 

 These processes can produce a metric ton of con- 

 centrated nitric acid (93 to 96 per cent.) at about 

 half the cost of retort (Chile nitrate) nitric acid. 

 Nitric acid can be produced by the oxidation pro- 

 cess from by-product ammonia, even at its highest 

 pre-war price, cheaper than by the old process. 



It may, however, be doubted whether any of 

 the synthetic processes, with the possible excep- 

 tion of the arc process in very favourable circum- 

 stances, can produce a nitrate' fertiliser that would 

 compete with Chile nitrate under conditions that 

 the Chilean industry might be willing to adopt. 

 Whilst improvements in the method of absorbing 

 and recovering the oxides of nitrogen in the arc 

 process are certain to occur, it must not be for- 

 gotten that the capital expenditure needed in in- 



