SOIL LIFE

Wairarapa Times-Age, 17 September 1942, Page 2

SOIL LIFE

PART IN PLANT GROWTH

IMPORTANT ROLE PLAYED.

MR H. N. BIBBY ADDRESSES ROTARY CLUB.

One’s interest' in the cultivation of the soil may be increased considerably by regarding it not as a medium to produce a few plants but as a soil teeming with life and supporting within it animal and plant populations, said Mr H. N. Bibby, in an address on “Soil Life,” given at today’s luncheon of the Masterton Rotary Club. Soil might be regarded as a mineral frame work, the particles of which were surrounded by soil solution supporting much of the soil population, said Mr Bibby. One of the most important roles of the soil was to act as a storehouse of water for soil life. The invisible organisms of the soil were mainly responsible for the present chemical codition of the earth’s surface and they played a very important part in the growth of higher animals and plants. The various groups covered were taken without regard to logical order and no attempt was made to deal completely with all groups or any group. All material was taken in by root hair as a solution during the few days they were alive, said Mr Bibby. The root system was very extensive, e.g., in the case of the oat it was 200 to 300 yards in length. Plants passed 300 to 5001bs. of water through their, roots for every pound of material built up. In the days of artificial manures, the tendency was to stress tne mineral constituents which were essential but made up a small percentage of the to-, tai weight. The materials which were derived from vegetable and animal sources, were of great importance. This was the work of bacteria, fungi and simple forms of animal life. In the case of bacteria, millions of them were engaged in various changes, including the change of materials to nitrates, which were essential to plant growth. Protozoa, the lowest form or animal life, certained types feeding on bacteria and consuming several hundred in their life time.. The benefit of soil sterilisation, which was once thought to be due to the destruction of protozoa, but it was now believed that the bacterial population might benefit by the presence of protozoa. There were hundreds of species of soil fungi, said Mr Bibby. Some types were largely responsible for converting humus to a form available to bacterial action. Mycorrhiza fungi must be associated .with roots of certain plants before growth was successful. As to eel worms, there were thousands of varieties, only a few of which were harmful. They abounded m sou with an excess of organic matter, ana many assisted in the decomposition of residues. Some of the larger ones consumed 50 to 100 of the harmful type daily. The work of earthworms was well known. Darwin estimated that in on eacre, ten tons of material passed through the digestive organs of worms in the course of a year increasing plant growth as soil cultivators The multipede was a vegetarian, and was often blamed for damage done to plants by eelworms. Centipedes were carnivorous, devouring worms and other forms many, times their own Sl The study of microbiology or soil science was in its infancy. The soi population made the ground what it was and sooner or later the study of this population would be recognised as of great importance in the advance of agriculture.