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Samples of brine, cured citrus peels, sterilizing-tablets, &c., have been analysed and advice given in connection with the operations of the Tauranga Citrus Association By-products Factory. Other miscellaneous samples include borax for purity ; cod-liver oil for vitamin A content; waters for salinity (for the Public Works and Marine Departments), for wool-scouring, for irrigation, for cobalt content (0000 l p.p.m. in Wellington tap-water), for the information of the Zoologist in connection with studies into the distribution of liver-fluke, and for stock consumption ; rat organs for copper, iron, and cobalt in connection with feeding experiments carried out by the Research Officer in Animal Nutrition ; a calculus from a sheep (presumably an enterolith) which proved to be a rare type composed of magnesium ammonium phosphate ; pig-urines for iodine content following iodopin injections (for the Director of Pig Industry) ; pastures for manganese determinations from farms on which grass staggers occurs (for the Officer in Charge, Veterinary Laboratory) ; mushroom composts for pH (from the Plant Research Bureau) ; and seeds for demonstration of a viability test using sodium selenite. Preliminary experiments were made for the Internal Affairs Department 011 the production of a poisonous lick to aid in the destruction of deer. Meetings of the Chemical Divisional Committee of the Standards Institute have been attended and the Department's interests represented thereon. Progress has been made with proposals for standards for pollards and meat meals. The usual routine testing of cattle-dips and meat-marking fluids, and preparation of glassmarking ink, have been continued. Chemical Control of Ragwort. The Agricultural Chemist at Ruakura, Mr. F. B. Thompson, reports as follows on investigations into the chemical control -of ragwort commenced in June, 1937 :— " The ragwort-plants growing under cultivation in the previously established ragwort nursery on the farm were used to study the conditions for the most successful use of sodium chlorate and to see if a better weed-killer could be found. " The first object was to trace the path of the chlorate in the ragwort-roots by chemical means, but this was not practicable as the oxidizing enzymes in the plants masked the chemical reactions of the chlorate. Fortunately, chlorate injury could be traced by a red coloration in the affected roots. " Applications of several grams of chlorate 011 rozette plants completely defoliated the plants with subsequent disintegration of the crown. The roots were killed for several inches from the crown, but after several months the remaining lengths of the roots, which were perfectly healthy, sent up shoots which grew into new plants. Thus the place of the original plant would be taken, by, perhaps, a dozen plants. " All the experiments, including absorption experiments from roots and leaves, indicated that the ragwort-plant has great difficulty in absorbing and translocating within its tissues sufficient sodium chlorate to kill the whole length of the roots. On the other hand, very little chlorate will completely defoliate the plant. Complete roots kills were obtained when sufficient sodium chlorate was applied. The doses had to be considerably larger than was first anticipated, the action, presumably, being by contact with chlorate in the soil. " In some of the later experiments difficulty was experienced in obtaining root kills even with large doses. This was attributed to the extensive root-development of the plants owing to the loose cultivated soil. Roots were found at a depth of 22 in., while others has a spread of over 7 ft. Ragwort-plants growing in pasture have not such an extensive root system, and better kills have been obtained than in the nursery. " In the later experiments emphasis has been placed on field experiments with ragwort-plants growing in pasture. The trials are to determine the quantity of chlorate required to produce complete root kills, the best method of application, optimum seasonal and weather conditions, and stage of growth. The effect of a vigorous pasture sward in choking out any live ragwort-roots resulting from chlorate treatment is being studied. The experiments covering these points include 120 treated and pegged plants on Ruakura Farm and an equal number on Mamaku State Farm, and over seventy plots on a farm near Putaruru. These applications were made in the summer and early autumn, and the results will not be available till the regrowth next spring has been determined. Further treatments will be made from time to time throughout the year. " Analyses of soil, which had been treated with chlorate were made to trace the movement of chlorate through the soil. The material tends to remain on the top few inches, and when it is removed from there it is quickly washed into the subsoil. " Comparisons were made between the effect of sodium chlorate on ragwort and on other weeds. Ragwort appears to be more difficult to kill owing to the limited translocation, but this point is to be investigated further. " The above remarks apply to sodium chlorate, but they are equally applicable to Atlacide, a commonly used proprietary weed-killer which consists largely of sodium chlorate and which has a similar action on ragwort. " Other weed-killers were tried on plants in the ragwort nursery —for example, the sulphates and nitrates of both copper and zinc. With each of these compounds it required approximately 15 grams to produce an effect similar to that resulting from 1 gram of sodium chlorate. Three groups of weed-killers, dichromates, thiocyanates, and bisulphites were compared with sodium chlorate and the compounds were tried when combined in pairs. In experiments, both at Mamaku Farm and in the Ruakura nursery, sodium chlorate proved to be the most efficient.

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