HOW NITRATES ARE FORMED.

Wairarapa Age, Volume XXXII, Issue 9614, 7 October 1909, Page 7

HOW NITRATES ARE FORMED.

(By A. B. Wood, Agricultural Cehmist). Much has been said regarding the 1 world's supply of nitrogen, in fact Sir William Crookos prophesied about I sixteen years ago, that if the cultivators of crops for the growing population which in the course of a few years would be doubted, tie supply of o:ie of the most important plant foods viz , nitrogen, would not be procurable 111 sufficient quantities to meet the demands. However, scientists have come to the rescue and have provided us with inexhaustible supplies, which will b3 dealt with later. The most important supply is the "free one," a supply always available, viz., gaseous nitrogen of the atmosphere, which certain plants not only assimilate for their own use, but puss successfully to other plants within reasonable lvach. Nitrogen forms about fourfifths of the whole atmosphere, combined with oxygen gas, an oxide is formed, which when'Jn contact with moisture'forms nitric acid., and last-

ly with the help of in the soil forms nitrates of_a soluble and : I readily available, ] perfected plant food. The soil being a most active agent and causing these gases to unite exactly where needed, and unless phosphoric acid and potash be present to assist the growth, this form of free supply of nitrogen is lost, and vigorous germ 3 of life known as "bacteria" are given a check, which takes a considerable time to. recover. Another free supply is in the form of rain water, of which 10.70 is in the form of nitric acid, the balance is in the form of ammonia. Dews and fogs are much richer in these elements. However, it is well known that the above free supply is not sufficient tor the large crops now required, but they are greatly assisted by careful preparation of the soil, so that the ni'rogen may have free access and supply the wonderful bacteria with food to enable them to increase and form nutriment tor the life of plant?. The weight of free nitrogen of the atmosphere is calculated to be 121b to each square inch of the earth's surface. Nitrogen as supplied by fertilisers; nitrate of soda, the oldest known chemical which supplies nitrogen, ammonia, equivalent to 3 5.23 nitrogen; also sulphate of ammonia, containing 23.00 amomnia, equivalent to 18.94 nitrogen; nitrate of potash 15.78; ammonia, equivalent to 13.00 nitrogen blood; containing about 11.50 nitrogen. These fertilis ers are too well known and do not require any introduction. They have and are doing their share to keep up the needful supply of nitrogen. There are now two new fertilisers which claim to be and under every test have proved to be the cheapest ] and most effective of all nitrogenous manures, viz., nitrate of lime and , calcium cyanamide. Nitrate of lime is produced by atmosphere being forced through a specially coimstrup- . ted electric furnace and so forming nitrogenous fumes absorbed by water; then combined with lime in suitable proportions to give nitrata of cal cium. This on analysis shows about 14 per cent, of nitrogen and 30 pit cent, soluble lime. This manure, when used on soil in want of lime, the result will be much better than nitrate of soda and not nearly so costly, and may be used with great advantage on the following crops:— Wheat, barley, rye, turnip?, potatoes, etc., in fact it may be applied to any soil where nitrogen is nteded. j This manure is very hygroscopic. Calcium Cyanamide is very similar to nitrate of lime, and is produced by heating calcium carbid3 in an electrical constructed furrace in the presence of nitrogen (atmospherical) the analysis of this being as follows: i —58.91 calcium cyanamide, 12 86 | carbon containing 20.62 nitrogen, [equivalent to 25.03 ammonia This , fertiliser may be used with safety as no bad effects have yet followed the use of this new discovery. Although it is well known that soluble niitrogenous fertilisers have a beneficial effect on crops, with a few careful experiments by farmers the uses and effect of nitrogenous fertilisers will greatly assist to make farming a more profitable oc

cupation. The seed of all plants contain nitrogen, there is usually from one to six per cent., and in the entire plant there is less than one per cent., there being no more nitrogen in the entire plant when fully grown than there was in the seed to begin with, lnnnculation of seed with nitro bacterine is little ; known, many failures having occurred owing to the fact that the soil was sadly in need of other plant foods in many cases found to be phosphoric acid, and in others potash, in the absence of either or both no j success may be looked for. In America the use of nitro bactrine was a failure on good foil. Soil deficient in nitrogen responded when a suitable supply of phosphoric acid and potash was present. The full value of tillage must not be naglected as this ia one of the influences which plays an important part, for when fertilisers bave to be applied it is well that they shoulla have a "clean house" to start to do their work, and not to expect a fertiliser to do entirely .all the work; too much is ! often expected of the fertiliser; the I latter cannot drain, is powerless at 1 tillage, and meets witn many difficulties in the shape of indifferent seasons.