Vol. XI. No. 254. 



THE AGRICULTURAL NEWS. 



21 



THE POISONING OF CATTLE BY 

 SORGHUM. 



The number of deaths among the dairy cattle in Queens- 

 land, in the year 1903, led the Department of Agriculture in 

 that State to a strict investigation concerning sorghum, with 

 a view of determining whether the mortality among the cows 

 was due to any poisonous constituents the plant contained. 



It was shown that in some cases fields of sorghum, with 

 only a dividing fence between, gave entirely different feeding 

 results, although the sorghum from each field was fed to the 

 cattle at similar stages of its growth. One herd would be 

 affected on one side of the fence, while the herd on the other 

 side, in a field immediately adjacent, thrived on the succulent 

 fodder. In each field the cows were grazini; on young sorghum. 



Dr. Maxwell and Mr. J. C. Brunnich, Chemists of the 

 Queensland Department, undertook to solve the problem, 

 which seemed at the time to have certain elements of mystery. 

 It was naturallj a puzzling situation to dairy farmers. With- 

 out definite proof they could not be convinced that the .sor- 

 ghum was responsible for the death of their cattle. 



It has been known to science for some years that sorghum 

 and similar plants, grown in rich soils, were more liable to 

 contain highly dangerous amounts of hydrocyanic acid — 

 commonly known as prussic acid — than when grown in soils 

 poor in nitrogen. It w.is found that the nature of different 

 soils very largely governed the amount of those poisonous 

 properties in the plant. This e.xplained why some cows were 

 affected through eating sorghum in one field, while those in 

 an adjoining field, consuming the same class of material, did 

 well. The changing character of the .•<oii varied the amounts 

 of prussic acid. 



In a specific case it was noticed that one field -in which 

 cattle were immune— gradually sloped upwards. The analysis 

 of the soil from this field showed a deficiency in nitrogen. 



To test the relation between the incorporation of the 

 prussic acid in the growing sorghum plant and the ratio of 

 the nitrogen in the soil, several plantings of sorghum v.ere 

 made in the Botanic Gardens at Brisbane, in soil composed 

 almost e.ifclusively of sand. One series of plants was not given 

 any special manurial assistance, while another series was 

 manured with nitrate of soda, a manure whose chief element i.s 

 nitrogen. This experiment was made in order to see whether 

 the supply of additional nitrogen to the soil would increase 

 the amount of prussic acid in the growing plant — nitrogen 

 being an element of that poison. 



Mr. Brunnich made repeated analy.ses which showed, 

 with almost mathematical precision, that the supply of 

 available nitrogen increases the amount of poison that 

 sorghum and other plants are capable of making and storing 

 up within their composition. 



1 )etermining the stages in the growth of sorghum when 

 the poison in it would be at the danger limit, was a very 

 interesting and valuable phase of the investigation. It was 

 found by the experiments that sorghum grown in highly rich 

 nitrogenous soils could not be freely fed to animals with safety 

 until the plant is preparing to seed. 



The sorghum plant — grown under the conditions 

 described — when very young, and from the age of three up 

 to seven weeks, contains distinctly daniierous amounts of 



prussic acid. After that age the poison rapidly disappears 

 by decomposition, the nitrogen passing over into other and 

 strictly nutritious elements of food. When the flowering 

 stage is reached, not more than a trace of the poison is 

 found. 



As the growth of the plant does not entirely depend 

 upon the age or the number of weeks since it was planted, 

 it is as well to .speak of its stages of development. It may 

 be generally stated that the sorghum plant is not safe for 

 feeding until it reaches the flowering or seeding stage. 



Dr. Maxwell reported that even sorghum, and such 

 plants as may be known to contain dangerous amounts of 

 prussic acid, may be judiciously used a green mixture with 

 dry hay chaff to make the feed tasty to animals. When 

 diluted in this way, the green sorghum being very carefully 

 stirred up and mixed with large quantities of the dry feed, 

 no harm will follow. The dry feed i.<, in this way, also made 

 capable of use. (The Ar/riciiltural GaiettK of Neiu South 

 Wales, Vol. XXII, p. 967.) 



THE PRODUCTION OP SULPHATE 

 OF AMMONIA. 



The report of the Chief Inspector of Alkali Works for 

 1910 shows that there were -^-tS works or separate processes 

 for the manufacture of sulphate of ammonia in England and 

 Wales, as compared with -oSG in 1909 and 52(5 in 1908, the 

 number having steadily increased from 449 in 1904. In 

 Scotland the number of such works was 104. There were 

 al.so fifty-seven gas liquor works in England and five in 

 >Scotland. 



Sulphate of ammonia is chiefly obtained as a by-product 

 from coal. When this is treated for the production of coal- 

 gas or for the manufacture of coke used in iron smelting, an 

 'ammoniacal liquor' results, which forms the raw material 

 for the manufacture of aiiiraonium salts. The distillation of 

 the bituminous shales used in the Scotch paraflln industry 

 also yields a certain amount, and the ammonia produced in 

 other manufactures in which coal and similar substances are 

 used, in iron works, from producer gas plants, and from car- 

 bonizing works, is also collected. The quantity of sulphate 

 of ammonia produced in the United Kingdom was 367, .587 

 tons in 1910, as compared with 349,143 tons in the previous 

 year, and 32-5,228 tons in 1908. 



These figures show an increase over the production of 

 1909 with the exception of that in iron works, which remained 

 practically stationary. The supply from coke ovens shows an 

 increase of nearly 10,000 tons. In 1904 the production in 

 coke-oven works was only 20,000 tons. The total produc- 

 tion in 1910 was 368,000 tons, and 284,000 were exported, 

 so that the l)alance remaining for home consumption for all 

 purposes amounted to 84,000 tons, as compared with 85,000 

 tons in 1909 and 91,000 tons in 190S. The exports of sul- 

 phate of ammonia are principally to the United States, Japan, 

 Spain, .Java and Italy. 



An expansion of ammonia production is anticipated, 

 owing to the further erection of recovery plants connected 

 with the manufacture of coke and fuel gas. Recent improve- 

 ments in design of sulphate of ammonia plant suitable even 

 for small gas works is likely to add to the total of sulphate 

 of ammonia production by enabling many small or incon- 

 venienly situated works to produce sulphate more econom- 

 ically than heretofore, whilst the recovery of this substance 

 from peat continues to receive attention, and may prove 

 a further source of production. (From the Journal of the 

 Hoard of' Af/rirultiDf, Vol. XVIII, p. 767 ) 



