FARMING NOTES

Te Awamutu Courier, Volume 56, Issue 4042, 2 May 1938, Page 3

FARMING NOTES

VISIT TO RUAKURA. CHILLER CATTLE EXPERIMENTS. RESULTS OF RESEARCH. Of chief interest at Ruakura Farm on my visit there recently was the progress of the experiments being carried out in the breeding and raising of chiller cattle, writes H.A.S. in the Dominion. The manager, Mr. T. E. Rodda, who is very keen on these trials, conducted me on an inspection of the many lots of cattle. There is one comment I feel should be made: cattle love the shade. Ruakura is generously planted with trees. It was a very hot morning and almost every lot of cattle inspected had to be routed out from under the trees. I feel certain that shade was good for them and that those fattening and growing chillers would be well advised to give attention to providing trees for both shade and shelter. The first mob seen were 14 months old P.A. steers born in January, 1937, and weaned in August. They were really splendidly grown. As with other growing cattle here, these are being regularly weighed. At last weighing the lightest went 616 lb, and the heaviest 7941 b, live weight. Allowing 751 b weight for the calves at birth, these have gained lilb daily to date. Should the growth be maintained these steers would kill at at 7001 b, dressed weight at 27 months—that is by April, 1939. The next mob were seven-month calves dropped July-August, and weaned last month. A fortnight after weaning they averaged 4901 b. They were the size of average yearlings as seen at the spring cattle fairs. The culls were very useful weaners.

As we came to a mob of cows suckling calves born October to midFebruary, Mr. Rodda spoke of cows with calves as being the best clean-ers-up of roughage of any cattle on the place. This mob had just made a great job of cleaning up the hill paddock and were now into a fresh paddock that required heavy grazing. The calves were thriving. Another mob of cows were out with bull and due to calve next December. They will then carry their calves through the 1939 winter to be spring weaned. One lot of cows weaned their calves only four weeks before dropping a fresh lot without any show of strain or upset. An important feature of these cattle trials is the dropping of calves out of season and then carrying them through the winter. They will thus be saved the winter check which is so often a severe setback to weaners. Then when they are here weaned they go on to the spring grass. Other work being carried out concerns wintering of cattle and rates of growth. Of interest to fatteners and to advocates of live-weight selling, of whom there are a number in the Waikato, is the conversion table for assessing carcase weight from live weight. Mr. Rodda gave this as follows:—Assume a chiller beast ready for drafting weighed 12751 b liveweight: Deduct 501 b for contents of pdunch, leaving 12251 b; divide that by 14—87 i; multiply that ’oy 8 and you have the carcase weight—7oolb. Discounting the paunch, this shows a 57 per cent, dressed to live-weight ratio.

Some months ago I mentioned the Ruakura ragwort nursery. This now looked a very sorry spectacle; chemicals, pruning and insects had all exacted a severe toll. Mr. A. L. Poole, who is in charge of this research, recently gave an excellent account of results to date in the “Agricultural Journal.” The features are that insects have yet to prove effective, that cutting and pulling is almost useless, and that chemical treatments are highly effective. FERTILISERS. Nearly all the artificial phosphatic fertilisers in use to-day are dependent on rock phosphates for their manufacture, and it is fortunate that numerous deposits occur throughout the world, says the New Zealand Journal of Agriculture. Such deposits vary extensively in type and quality. The largest deposits occur in America, North Africa and Russia, while the richest deposits are found in the small islands of the Pacific. All these are what are known as hard rock phosphates. Soft rock phosphates or phosphate guanos are deposits which may contain a small percentage of nitrogen derived from the accumulated droppings of sea birds and which would ultimately become a hard rock phosphate deposit. In the African and American fields the phosphate occurs as sediments, pebbly or otherwise, mingled with other rocks, and is very variable in quality. For the present we will consider only Nauru and Ocean Island rock phosphate which is by far the most important to New Zealand. The origin of these deposits is not quite clear, though it is probable that the reaction of guano and lime coral over countless centuries have produced them. For many years they were unknown, and actually their discovery was an accident. How im-

portant this discovery was can readily be understood when one realises that these are the richest deposits in the world and that Australia and New Zealand both have an outstanding phosphate deficiency. In rock phosphate, phosphoric acid occurs as tricalcic phosphate, often combined with an element called fluorine. Tricalcic phosphate itself is only slowly soluble in water—hence the treatment of rock phosphate to make the more available superphosphate—and the amounts of fluorine present have a marked effect on the availability of phosphoric acid content.

Nauru and Ocean Island phosphates contain from 85 per cent, to 90 per cent, of tricalcic phosphate, which is an extremely high standard for a natural product and equivalent to 39 per cent, to 40 per cent, phosphoric acid. In addition, the amount of fluorine present is small. The control of these islands is in the hands of Great Britain, Australia and New Zealand, the two later countries taking the bulk of the supply. Since the deposits were opened up tremendous improvements have been cade in working, handling and transportation, until now we have an economic and efficient supply of high-grade rock coming into New Zealand. Over the last eight years the average importation has been approximately 150,000 tons, most of which is used in the manufacture of superphosphate. RAGWORT CONTROL. RUAKURA EXPERIMENTS. Important research work into the ways and means whereby ragwort can be successfully controlled is now being carried out at the Ruakura Farm of Instruction and the following comprehensive survey of the work that is now occupying the attention of research workers at the farm was given by Mr. P. W. Smallfield, Fields Superintendent to the Department of Agriculture. to the first meeting of the Farm Advisory Committee at Ruakura last week. Although sodium chlorate has been used for a number of years to control ragwort, it has been found that under field conditions, and as commonly applied, it does not give a complete kill. The reappearance of a number of small plants following applications of chlorate are usually due to regrowth from roots which have been incompletely killed and not necessarily from seed from neighbouring farms. Although sodium chlorate has this limitation there does not appear to be any other weed-killer that will as economically carry out the necessary defoliation of ragwort plants. The first experiment was to trace by chemical means the path of sodium chlorate through the plant tissues. Chemical tests for chlorate are based on its oxidising properties and these tests are also given by the oxidising enzymes present in the plant. Hence chlorate could not be traced chemically, but fortunately, this was coun-ter-balanced by the fact that chlorate injury in ragwort roots gives a red coloration and could be traced by observation. The next stage was to see how the plant was affected by chlorate. When rozette plants, 15 inches in diameter, were treated with 0.7 gram of chlorate in a 5 per cent, solution, the chemical was absorbed fairly generally by the leaves and transported by the conducting tissue to the roots where it appears in the cortex, and not in the conducting tissue. The chlorate travelled down the roots for a distance of six inches in the 14 days following treatment and within the next fortnight there was only a slight further spread. All portions of the plant above ground and the affected parts of the roots gradually rotted away till there was no sign of the plant The remaining lengths of root were perfectly healthy, and in time many of them grew into new plants. Thus, six months after treatment, the original plant was replaced by, perhaps, a dozen young plants. Later Experiments. In later experiments, the amount of chlorate was increased from 0.7 to 20 grams (one gram is 1-28 of the ounce) and some of the plants receiving these larger does are recovering. The difficulty in obtaining complete root kills in the Ruakura ragwort nursery, was in part, attributed to the loose, cultivated soil, which favoured an extensive root development, plants being obtained with' a root spread of over seven feet. Consideration of these points led to the plants being sprayed in blocks instead of individually and also to more emphasis being placed on field trials. In general, ragwort in pastures has not such an extensive root system and preliminary examination of some of the plants in pasture already treated suggests that they will have better root kills than those in the nursery. The more compact soil, the mass of grass and clover roots, and the smothering effect of the pasture will make it more difficult for the remaining live roots to regenerate new plants. Considerable attention is being paid to this and a number of plants in Ruakura pastures have been treated with quantities of chlorate varying from 5 to 100 grams. In place of the plants there are now dead patches which will later be topdressed to facilitate grass dominance and the choking out of any remaining live ragwort roots. The difficulty in obtaining complete root kills is attributed to the inability

of the ragwort plant to translocate within its tissues the absorbed sodium chlorate. This was illustrated by an experiment on plants growing normally in the ground, in which rooti were placed in chlorate solution of varying strengths. In another series of plants the leaves were placed in solutions. The sections of the plants adjacent to the immersed portion died away, but not one of the plants

was able to absorb and translocate sufficient chlorate to kill the roots. Leaf absorption from the strongest solution was most effective, but even then the root penetration was very slight. These results considered in the light of the earlier observation that the chlorate is present in tne roots mainly in the cortex, suggests that the poor root penetration following foliage applications may be due to

the chlorate not getting into, or not remaining in the conducting tissue of the roots where it could be translocated. On. the other hand, American workers, using other plants, have had chlorate penetration in the roots to considerable depths. At present, experiments are in progress ?t Ruakura to compare chlorate penetration in ragwort and other weeds to see if the ragwort root is peculiar in any respect.