GROWING RUBBER

Timaru Herald, Volume CLIII, Issue 22470, 4 January 1943, Page 4

GROWING RUBBER

Dominion Experiments

Tests With Russian Seeds

Experiments to determine whether rubber can be economically produced in New Zealand are now being carried out jointly by the Department of Agriculture and the Department of Scientific and Industrial Researech. Seed of the Russian rubber dandelion, kok-saghyz, has been obtained from Australia, and plots have been planted in Hamilton, Blenheim, Hastings, Timaru, Central Otago and Nelson. The immediate project is to secure data about environmental and cultural requirements, yield of rubber at various stages of growth, methods of processing and production and viability of seed. “If successful,” states Mr R. E. R. Grimmett, chief agricultural chemist, “seed stocks will be built up and no doubt a programme of plant breeding will be initiated.” The remarkable productivity of the lubber tree, hevea brasiliensis, under tropical plantation culture, tended before the war to discourage interest in rubber-producing plants more suited to temperate climates, but from 1931 to 1933 Russia, in an endeavour to secure self-sufficiency in raw rubber, tested many plants for rubber content at d found kok-saghyz suitable and adaptable to cultivation on an extensive scale. An indication of the Soviet’s idea of the value of the product is given by the fact that in 1938 Russia was reported to have 170,000 acres under cultivation and to be planning to increase the area to 2,500,000 acres.

Though rubber can be produced from several plants of the milkweed family already growing in New Zealand, it is considered by experts that kok-saghyz is probably the only means within sight for the short-term production of rubber in the Dominion. However, experiments are also to be carried out with guayule, a woody perennial shrub, native of central Mexico, which has been successfully exploited as a source of rubber in southern California since 1904.

Kok-saghyz is highly adaptable as to soil and climate. It is cultivated from the south of Russia to the Arctic Circle. Best results are secured from rich soils and a somewhat complicated manuring programme has been develoned in the Soviet Union to obtain maximum yields.

Information available about the plant’s behaviour as a farm crop is rather contradictory, but Dr Paul Kolachov in a bulletin published by the National Farm Chemurgic Council of the U.S.A. states: “If the crop is harvested at the end of the first year, kok-saghyz plants yield an average of 4500 to 5500 pounds of cleaned roots an acre, which equals 150 to 200 pounds of crude rubber, and 75 to 100 pounds of seed. If the crop is left for a second year, the average yield is 2700 to 3600 pounds of root and from 100 to 150 pounds of seed. In some cases the yield at the end of the first year is as high as 7000 pounds of root, which, of course, gives an even larger amount of crude rubber. At the end of the second year, the percentage of crude rubber is higher, but the yield of the roots is less, since the plants have been thinned out by the frosts of the preceding winter, have been attacked by rodents, and the roots have been spoiled by their tendency to work up through the crevices in the soil.” The botanical side of the investigation in New Zealand is being conducted by the botany division of the Department of Scientific and Industrial Research, and field plots are being established by the fields division of the Department of Agriculture.