NEW METHOD OF NOURISHING PLANTS.

Golden Bay Argus, Volume XII, Issue 47, 21 April 1910, Page 3

NEW METHOD OF NOURISHING PLANTS.

MANURE FROM THE ATMOSPHERE. Professor Bottomley, of King's; College, has been investigating the absorption of nitrogen from the air by plants and its fixation in the soil in a form suitable as a plant food." In agricultural operations quantities of nitrogen are removed from the land in harvesting the form of nitrates, which the plant has built up during the process of its growth. In consequence of this need for nitrogen by the plant, manuring with ni-trogen-containing products becomes one of the most necessary condition: of successful agriculture. The construction of nitrates from ammonia and nitrites has long been a familiiar process, but for many years the free nitrogen of the air, owing to its chemical inertness, was deemed of no service to the plant organism. Under certain conditions, however, fixation of atmospheric nitrogen has been conclusively proved during recent years and both practically and theoritically it is a phenomenon of the greatest importance. The Leguminosae (the order oE plants which have pods as peas, beans, etc.) have long played a special part in agricultural processes, frot only because they grow in sterile sandy soils without any addition of nitrogenous manure, but be* cause they actually improve such! soils and make them suitable for the growth of plants which do not belong to that family. The fact that the growth of a leguminous crop was the best possible preparation for the subsequent raising of a vigorous wheat crop was noticed by farmers, » but the explanation was not so patent. High scientific authorities, both in England and on the Continent, were, Mr, W. J. Uglow Woolcock mentions in the 'Pharmaceutical Journal,' engaged in the elucidation of this problem, but for many years without definite result.

CURIOUS GROWTHS AND THEIP USE.

It was in 1888 that Hellriegel ,nnd Wilfarth announced their discovery that the nodules on the roots of leguminous plants .were caused and inhabited by living organisms, which utilised the nitrogen of the air and supplied the same to the pla,nt in an available form. Hellriegel and Wilfarth in their classic experiments planted certain Leguminosae (peas and lupins) in very pure quartz sand which had been previously freed! from all micro-organisms by sterilisation. Certain cereals (oats and barley) were treated in the same way. In each case it was found that growth took place onlyxpn the addition of nitrates. A very important difference was notioed, however, as soon as a small quantity of an extract of arable soil had been added to the sterile soil* free from nitrates, The Leguminosae showed a remark* able gain in nitrogen wnich could only have arisen from the employ? ment of atmospheric air, but in the case* of cereals the addition of the soil extract produced no result.

The effect of the soil extract must have been due to the activity of mi* cro-organisms present aud not to the amount of nutrient which it con» taiwud, since, on heating it to a tarn* perature of 70deg. 0., the effect waa nullified. Again, the organisms must be such as have special relationships with the Legiuminosae, since* there was an absence of any result in the case of the cereals. Further it was shown that different Leguminosae require different microorganisms, since the extract of a soil in which peas would have been cultivated, but in which no lupins had ever been grown, furthered the growth of peas only, and not of lupins.

Thus, Hellriegel and Wilfarth showed in the clearest way that the microorganisms present in the soil extract were the cause of the formation of the nodules on the roots of the Leguminosae, and that these plants could assimulate atmospheric nitrogen only when the micro-organisms were present in the root nodules. Also, they showed .that it is not sufficient merely,that any kind of lower organism should be present in the soil, but that it is essential that certain species of the latter should first of all enter into symbiotic (united) relationship with the legu-. minous plant.

In 1906 and 1907 over a thousand j packages of cultures of bacilli wenn distributed free over the United; Kingdom from King's College, with the object of thoroughly inoculating") the roots of the leguminous plants in ' the fields. The reports sent in by. farmers and gardeners show that a markedly increased crop resultd in B 0 per cent, of the cases in which the bacillus culture had been used. At the present time plants othei than leguminous are being experimented with in the laboratory. Professor Bottomley has been ablo to produce new forms, or rather physiological varieties, of the first discovered bacilli, which are capable ofi symbiosis (united life) with various other green plants. These mm varieties of bacilli are able to fix atmospheric nitrogen, and supply at* trogen compounds to the various plants which Professor Bottomley. has infected with them. i

On one series of experiments ton Bacillus radicieola was "starved " g the bacilli were taken away front their favourite food, the legurataow root, and bred for ten generations in an extract of tomato roots. Th© new descendants are reported to have' acquired a taste" for their new food, ! and the result of "sowing " the soil in which tomatoes wero grown with the bacilli was the occasional forma-. tion of nodules, and the very maiked improvement of the crop. K.'milar treatment has boon followed in tie case of cereals, roses, cal'frojgcs. and strawberriees. In »v«*y case, "Mr, Woolcock concludes, th" yield has been improved r an% thf* enriched* —"Popular' "'•'' ;