THE SPIRIT OF THE SOIL.

Taranaki Daily News, 31 May 1916, Page 2

THE SPIRIT OF THE SOIL.

~— •— '■ / (By 'Mr. H. G. Sergei, Agricultural Lecturer to the Technical School). Jn Taranaki to-day the matter of agricultural education is gradually becoming recognised as a thing of, value to the farmer and "omiminity generally. To those who do try to observe and learn some of the principles underlying husbandry, the book called "The Spirit of the. Soil" will come as an inspiration. This book appeals to the lover of Nature and grips him right at the start. "Picture an observer suspended above the equator of the earth, unaffected by the swirl due to the earth's turning on her axis, but following closely her movements through space. Assume that at an instant of time he drops a bacterium on the hurrying surface beneath his feet, and that the bacterium, like the seed of the sower that fell on fruitful fround, falls into a medium ideal for its growth and finds nothing to check its power of reproduction. In twenty-four hours, when the same spot of tie earth's surface was again beneath his feet, he would find, instead of the single bacterium he had dropped, a bacterial empire one hundred and seventy thousand times as numerous as the present human population of the world." In this graphic way the author indicates the enormity of the number of bacteria, and claims, just as in medicine and in the arts, that the science if bacteriology has very richly repaid the labor -spent oft it, so horticulture and agriculture shotlld not prove exceptions to the rule NITRATES. first we Jiave the nitrate problem of the world placed before us. The natural deposits have exhaustion in sight. Practical means of inducing the nitroges of the air to enter into combination with oxygen and form nitrates requires the utilisation of enormous power, with pos- | sibilities of increased cost, and it is to bacteria of the soil that we loek for a way out. Then the author tells us in a most readable way how an English man of science set out to facilitate the work of soil bacteria, and how he has been foveed to believe in the existence and potency of certain mysterious accessory food substances produced through the action of bacteria, which develop plant life beyond the action of manure, natural or artificial. The functions of soil bacteria an* the way thev lead to an increase in soil fertility "are next dealt with. "To-day we are beginning to know that the soil which the gardener turns with the spade is the site of countless vast empires of bacteria. They are empires that rise and fall in.the short space of weeks, that have great tasks to perform, and that devote themselves wholeheartedly to carrying them out—empires liable to ; countless vicissitudes. Now they are overwhelmed by the vast immigrations that come to them suddenly as gardener «r husbandman pours into their borders countless myriads of individuals with each spadeful of his manure. Periods of drought wreak havoc on their colonies, the'lives of whole empires being dependent on the chances of the climate. They are preyed upon by monstrous protozon that may exact a greater toll than even they with their astounding fertility can pay; or they may perish through their own activity, their life being clogged by the products they have themselves formed. To a bad environment or a good one they respond as readily and as notably as the people in our great cities." Only within recent years have we realised how intimately our prosperity is dependent on the bacterial population of the soil. Without bacterial activity it would be ot no avail for the farmer to dung his crops; it would be useless for him to attempt to enrich his soil by ploughing in green stuff. The plants and trees that have lived and died wresting carbon from the air would only cumber the land. All vegetation would be choked, and the earth, would become a vast wilderness, unbeautiful and silent, save for the winds and seas. Then we have the protozon. the enemy of soil bacteria, described, thus: "The protozoa is not a bacterium, but a minute animal requiring the magnification of a strong microscope lens to be seen. Small though he is. he is as terrible and monstrous a foe to the bacteria as the vast swamp monsters must have proved to emerging man in the Eocene times. Looked at in witter under the micrseope he is seen creating, in the medium, whirlpools against which the hapless bacetria are powerless to contend, and drawing them defenceless into his body." Fixation of nitrogen by leguminous plants forms the subject' of the next chapter, and a description is given of the elforts made to commercialise cultures.' Then comes the most fascinating portion of the book, dealing with the bacterialised plant. We are told how peat in its raw state contains no soluble humus, thai it is acid and therefore unsuitable as a home for nitrogenfixing organisms, and requires perhaps a two years' exposure before available nitrogen compounds are evolved. However, in the laboratory of King's College. London, the quick conversion of this insoluble peat into a material rich in sol- , üble plant food was accomplished by a process controlling air supply and temperature so as t» give certain aerobic bacteria conditions under which they could work best. This was indeed a notable achievement. After this had been done steam was forced through the mass, and all organisms were destroyed, Hie result being a sterile medium, which was inoculated further with two organisms which multiplied rapidly and permeated the mass. When this was accomplished the peat was dried and was then ready for application to the seed or the soil. A valuable point brought forward is that peat contains available phosphate and potash. Next comes the' most important chap- ' ter, wherein there is detailed the discovery of accessory food bodies (mainly as a " result of researches undertaken on disease). The physiological term for these bmdies is "vitamines," and they must be present in every diet tor every animal to remain healthy. "Since the year 188(1 when Vordennann put for- [ ward the theery that beriberi occurred after the long-continued use of milled rice—that is, of rice from which the outer layers of the grain had been artificially removed—a whole group of diseases'has come to foe recognised under ; the common name of 'deficiency diseases.' They comprise beriberi, scurvy ■ and others. Vordermann's view was not long in receiving confirmation, and the further fact was soon noted that peri sons whose diet consisted of uninilled ; rice were exempt from the disease." ; The problem was attacked chemically, ■ and Funk isolatcJ a substance from the 'lahoholic extract of rice-polishings which I j appeared as colorless, needle-shaped ' crystals, and was markedly valuable for ■ring experimental beriberi. ViUminc3 were then found in yeast, "Jilfejolks gf egge, meat, wheat. n«.ts

and barley, but not identical ia character, yet in .cry minute quantity. For instance, only the ten-thousandth part of the rice consists of vitamines. The influence of vitaminc growth was emphasised by experiments also. Feeding young rats on a diet of white bread arrested growth, but they flourished on whole-meal bread. Experiments with bactcrised peat produced surprising results, indicating that it bad growthstimulating qualities that could not ibe put down to known manurial constituents present; so it was decided to follow the method adopted by Funk for the isolation of beri-beri vitamine. A dry substance was obtained in minute quantity which, tested with growing wheat seedlings in water culture, stimulated the growth of the plants to an unusual degree, and enabled them to use the food supplied. Professor Bottomley describes the bodies extracted from bacterised peat as auximones (from 4 fireek word, auximor, meaning "promoting growth'')! A further experiment showed that treating growing bacteria with these auximenes had also a great influence on the growth of these nitrogen-kxing organisms. The testing of humogen or bacterised peat gave amazing results, many instances being given of great superiority over artificial manures. With potatoes peat-treated land showed an increase of 53.3 per cent, over the unmanured land, as against the increase ijiven by artificial manures of 27 per cent. It is to be hoped "The Spirit of the Soil" will 'be widely read; aitd, further, that experiments will be conducted with humoge» j