CARBONIC ACID GAS AS A FERTILISER.

Otago Witness, Issue 3511, 28 June 1921, Page 8

CARBONIC ACID GAS AS A FERTILISER.

Every plant (says Chambers’s Journal) contains a large proportion of carbon in its composition, and this element is now generally admitted to be derived from the atmosphere by means of the leaves, ill spite of the very 'small proportion of carbon, .03 per cent., to be found in fresh air. It is only reasonable to suppose, therefore, that by increasing the percentage of carbonic acid gas, known by chemists as 002, in the air around growing plants, their growth will bo accelerated. But in order to make such a method commercially successful a cheap and abundant source of carbonic acid gas must be found. As is well known, the gases escaping from all fires contain -his gas; but a particularly large proportion distinguishes those discharged from. blast-furnaces. Founding on this fact, Dr D'iedel, of Essen-on-Ruhr, has patented a process whereby growing plants’ are supplied with blast-furnace gases after they have been purified from their noxious constituents, such as sulphur. in ©refer to test the process, a greenhouse was supplied with the purified gases by a number of pipes, these being run backwards ami forwards over the whole length of tile room, and punctured at intervals for tlio escape oi' the gas. Two other greenhouses, without any gas supply, wore tested at tli© same time to obtain comparative results. Experiments were begun about the middle of June. Tue effect of 1 he gas upon a castor-oil plant was to produce leaves more than a metre

in width, whereas in the two other greenhouses the leaves reached only about half that size. Tomatoes increased in weight by 175 per cent., cucumbers by 70 per cent. Open-air experiments were also.-tried in suitable plots of land, around one of which was a pipe with holes at intervals, through which the carbonic acid gas was continually cscapmg 002, being heavy, would, of course lie along the surface of fie ground. In the ouen air tll<? , y; _ o£ spinach Wa3 found to’ bo gieater by 150 per cent, in the gas-supplied plot, while potatoes increased bv 180 per cent., lupines by 174 per cent., and' barley by 100 pei cent. Later teste on a much larger scale have shown an increase in a potalocrop of 300 per cent. According to the inventor s opinion, as set forth in the Scientific Anierican, carbonic acid gas works for supplying agriculture will before long be quite as common a feature as electricity and gas works, the large industrial centres at the same time becoming centres of increasing agricultural production. Careful analysis has shown that no danger to the health of man is threatened' by the additional amount of carbonic acid gas contained in the air where the system is in vogue.