SOIL FERTILITY

Hokitika Guardian, 31 July 1928, Page 4

SOIL FERTILITY

INFLUENCE ON PLANT LIFE

LECTURE BY Mll E. B. LEVY

CHRISTCHURCH, July 30.

Stating that all pasture lands had a standard of fertility that must be maintained if grasses and plants were to thrive successfully, Mr E. B. Levy, during the course of a lecture on Saturday evening to the Canterbury Agricultural Science Club on “Pastures,” stressed the importance attaching to a study and treatment of not only the plants but the soil itself. Plant life depended on the fertility of tho soil and the conditions of weather, climate, etc., to which the soil and the plants were subject. Mr Levy, who is Agrostologist to the Department of Agriculture, illustrated his lecture with lantern slides, showing tho growth and development of both field and forest life. Ono slide showed two adjacent paddocks which originally had grown cocksfoot. For eighteen months stock had grazed in one paddock, which was then supporting white rye, which had, through the influence of grazing, killed off the cocksfoot. In the next paddock, which had not been subject to grazing, cocksfoot was the dominant plant. Besides grazing, climate, temperature, light and shade, humidity, and winds were factors which changed the nature of the land, and consequently the nature of the plant.

Soil fertility governed the growth of plants. Over 95 per cent of plants utilised the ordinary fertility in the soil. There was a complex relationship between the kind of plant and the kind of food. Vegetation depended on tho modification of the habitat, continued Mr Levy. Trees altered the country. In mountainous country the habitat was seldom changed. A single patch would remain the same until the shingle was moved. A sea beach was a similar example. The sand being blown about and shifted continuously, no change was made. But if the sand were stabilised, succession would be created. So long as there was some potent factor stable there would be no modification of the habitat. Til mountainous country the climate jvas the main factor. Climate was not so important on the lowlands. On tho grass lands, stocking, burning and growing were the factors to bo considered by the farmer. Plant competition became operative. The study of natural vegetation was important in tho study of pastures. By lantern slides the lecturer showed the different phases and different types of forest growth. No matter what the land—tussock land, forest areas or mountainous couptry, the modification, whether by plough, by man, or by nature, of the habitat governed the conditions. Tussock land could be regarded as the cover of the primitive land in New Zealand before the forest development began. The fertility of the soil was getting back to bedrock when danthonia and other inferior grasses made their appearance. Rfttstail was coming in and was wiping out the indigenous danthonia. Plants such as red clover, white clover and lucerne required certain conditions before they could thrive.

Each pasture group bad a standard of soil fertility that must be maintained in order that the species of that group might thrive. Cocksfoot, ono of the best species of grass, called for the best conditions. Stock affected the grass, but the climate and temperature, and their benefits to the fertility of the soil, were also important factors in the growth of cocksfoot, which grew better oil hilly country. Grazing on cocksfoot Would retard the growth of the grass. Given perfect conditions, it would smother the growth of other grasses and plants. A paddock of cocksfoot was changed in eighteen months to a paddock of rye through the grazing of stock in the paddock. Before the- area was grazed, cocksfoot was dominant, but the new fertilisation and the feeding of the stock changed the ground to a habitat conducive to the growth of the rye and not of cocksfoot. Rye should be dominant in grazing lands. In Canterbury this could be attained by ploughing. In other districts change in the conditions caused the change in the*habitat which resulted in the growth of rye. If high production rye grass was to be obtained, the habitat would have to be improved. If present conditions, varying from flood areas, feltile areas to dry, barren, infertile areas were maintained, there would lie a low production of the plant. In Canterbury, he felt certain, there were many typos of rye, and if the strains were mixed and sown together the habitat range would be enlarged.

Mr Levy was accorded a vote of thanks for bis address.