Nelson Evening Mail. SATURDAY, OCTOBER 27, 1917. FACTORS IN FERTILISATION.

Nelson Evening Mail, Volume L, Issue 175, 27 October 1917, Page 4

Nelson Evening Mail. SATURDAY, OCTOBER 27, 1917. FACTORS IN FERTILISATION.

GREAT progress has been made with the science of agriculture in the last hundred years, and it is hoped that-, the lessons . taught by the war will bear fruit in the future by greater scientific investigation in the Tealm of agriculture. In place of the crude chemical determination of soil constituents the soil fis regarded-- in the light of a mediumin which countless myriads of micro-organisms have their being and; exert their activity., and that it is through their agency that all the higher forms of plant life exist. It is to Pasteur that we owe their discovery, but even when their presence •.had been' made known it' was •not recognised that they were in' any way connected with the soil's fertility or that thev played anv part in rendering it.so. Fred "Wlhittertbn, F.R.M.S., deals with these factors in fertilisation in a very informative matter, and his main points are of very general interest. To these teeming- myriads of lower organisms, -which it must not 'be forgotten : _ belon- to the vegetable kingdom, we owe, he says, th e dissolution of plant and. animal remain® and' -byi their decomposition the elemental substances from which, they Were originally built up are returned to the' soil, and again mad© available If or plant food', and thus from the asTies, as it were, there arises, Phoenix like, a renewed cycle of life. As it is only within a comparatively recent period that we have learned, to recognise" the •important part •these denizens of the soil play in the economic history of the world's food supply, so also have we only recently acquired- th e knowledge tbat without their unceasing aid the farmer could manure his land, apply all kinds of costly fertilising materials, but it would be labour ip vain and money wasted. The organic and some form's of_ inorganic matter thus applied 1 would simply remain inert. No change of any- '•moment woulda.take place if these microscopic beings, the' bacteria, were not present in the soil. It is, therefore, by their agency' that the organic' matter is resolved into carbon, dioxide, water,, nitrogen, ammonia, calcium arid so on, and riot only do they accomplish this and increase; the soil's fertility, but improve its texture abd water-holding capacity, a most important factor iii drier areas.

It must be clearly recognised, he ■goes on to point out, that several species of bacteria are engaged in the work off fertilisation, or', more correctlyspeaking, of breaking down the various chemical .compounds, and where on? species leaves off another species takes ut> the work. For instance, one of the nitrifying species of bacteria resolves or oxidises ammonia into nitrites, and then another group takes up the work and transforms the - nitrites into nitrates. T/lie fixation of atmospheric nitrogen is du e -to. another species of bacteria, and abundant as the supply is, .being nearly four-fii*hs of the atmosphere, and so vital to pilant life and the needs of humanity, yet plants cannot, without the intermediaryi of this particular species, -utilise one atom of it. We are apt to think of bacteria and their work more from the standpoint of the diseases produced in ourselves and animals, but one may credit' the work of these microscopic organisms as not being to cause disease, hut to fill some special function of a totally different character. The disease produced iy their action is incidental, not essential, to thenbeing. To put it broadly or plainly, we owe our very existence to these myriads of microscopic beings, and- it is to their efforts that the world is kept ■clean and sweet and capable of support, ing" life. The bacteria of the soil have their activities and their beneficial' actions which result from their woi'k very seriously curtailed, and it now remains to show how and .by what agency this is effected. The evidence available goes to show that other organisms of a totalfly different character to bacteria constitute a factor limiting their activity and at the same time the soil's fertility. These organisms, known as .protozoa, 'are. as the name implies, at the base of the animal scale,' and require, like the bacteria, magnification under the microscope' "before their presence can be seen. There are many, different spcies, including the Amoebae? (Plenro-trichia, Colpoda, and numerous others, and these organisms would appear to be of universal occurrence in all soils. Their structure is marked bv extreme simplicity, as'there is no fign of differentiation of organs, which is characteristic of the b : "her animals. Experiments have proved, that these animals, small as they are, seriously

check the bacteria of the soil because of their rapacious habits of devouring them, thus limiting- their uurober, and in so doing check the rate at which ammonia is produced. This must of necessity affect the growth of plants, as the soil is so much the less fertile.

The question naturally arises, says th e authority quoted, Can nothing be done to check the ravages of these predatory protozoa? In this direction the study of their behaviour towards chemical and physical agents opens out a promising field for research. It has been said that a sharp, hard frost conduces to increased crop production. From this it would appear that extreme cold will kill many protozoa, and the heat death point appears to be about 130deg. Fahr. It would appear that there i s a considerable amount of work to be done in studying the relationship existing between 'bacteria, protozoa and fertility. The varied conditions governing the growth and decay, or the appearance or disappearance " of the micro-organisms are the real factors in rendering the soiT a medium for plant growth and for increased production at a_ less cost. It might therefore be possible, he concludes, by further investigation of the organisms contained in th e soil and by eliminating the foes of the bacteria to produce from one hundred acres an amount equivalent to that from three or four hundred acres.