FARMING NOTES

Bay of Plenty Beacon, Volume 4, Issue 184, 24 November 1941, Page 2

FARMING NOTES

SERPENTINE SUPER

THE NEW FERTILISER Owing to the l'acl that it is not ret very well known there has been only a limited demand for the new superphosphate — Serpentine super, lit is now evident that results equivalent to that from ordinary supei tire being obtained in this district. At this time when superphosphate supplies are short farmers can wel 1 be advised to exploit more fully the use of this new superphosphate for the following reasons-:— 1. Approximately one-third morn land can be topdressed due to I ton Tcwt being allowed for every ton of ordinary super—the rationing being based on the phosphate content. 2. It is much more pleasant i<" handle especially for hand topdresstug. 'A. It can be stored for long periods -without any material effect op its quality, either physically or chemically. 4. As it is in a reverted form and basic in character it does not have the detrimental effect on bags when in storage. 5. It does not "cake" as does super, and runs more freely in the drill or topdresser., 6. Since it is, a reverted phosphate it does not have the detrimental effect on germination of small seeds such as turnips or swedes when sown in contact. 7. This reverted phosphate dissolves more slowly in the soil water and actively growing plants avill obtain much more of the phosphate before it becomes, 'fixed' in the soil, than would be the case if the watersoluble phosphate, such as ordinary super, were used. 8. The ground serpentine reel; used in the manufacture of serpentine super (3 parts super to 1 part terpentine) is a magnesium silicate which is an important compound amongst those necessary for plant development. The small amount of cobalt present in serpentine may not be sufficient to counteract any deficiency of that element, though in some cases it has been found to have increased the uptake of cobalt in the pasture herbage. Further investigation is being made in relation to the cobalt content at the present time. These points will serve to ~sliow that serpentine super has a definite place in modern farming practice and that its use is not just a gamble. It has been tried out and has given every satisfaction. Serpentine super is not a substitute for lime and so these who have been in the habit of using lime in their fertiliser mixtures need to continue its use to provide the same type of mixture. From a national standpoint the use of serpentine super assists in the conservation of phosphate the supply of which has been the limiting factor in the quantities, of phosphatic fertiliser available. Though by now farmers will have placed most of their orders for the limited amount they have been allocated, there is still time for those w T hose orders are yet to be placed, to obtain the advantages of the use of serpentine super, not only for topdressing yet to be done, but for use with crops and the sowing down of new pastures following crops.

A BRIEF HISTORY OF SERPEN-

TINE SUPERPHOSPHATE

A short history of events loading up to the present manufacture o\ serpentine super is of interest because of the potential qualities that it possesses and its importance in future topdressing and manuriaJ programmes of farmers. The name Serpentine Superphosphate has been given on account of its being a mixture of superphosphate witii ground serpentine in the proportions of three parts of the former to one of the latter. Serpentine is a silicate mineral with much magnesium and some iron with more than a trace of cobalt, the latter being the element used in the control of "bush sickness" of stock.

English workers in 1927 were ar-

in plant nutrition than was imagi

cd. German and Russian scientists were making investigations along similar lines and the results of their work Ave re published in 1932.. The effect of silicates on the efficient use. of phosphates by plants Avas studied by German Avorkers mainly, while the Russians were working on the possible use of a dunite rock (usually containing the mineral serpentine) to counteract the rather acid typV of superphosphate being used in that country. lloAvever only small amounts of the dunite rock Avere added to the superphosphate.

In New Zealand our workers followed up these results and Mr J. J. Comes of the Dominion Laboratory analysed samples of dunitc from Milford Sound and be found that the magnesium present was very soluble in dilute acid. In 1938 Mr C'ornes and Mr R:. El. R. Grimmett, Chief Agricultural Chemist, collaborated in an investigation as to its possible use in reversion of superphosphate. It Avas concluded that approximately 20 per cent of dunite Avas needed to obtain complete rcvcrsion-

Working in conjunction with the Soil Survey Division small experimental quantities of silico-super-phosphate (the name than given) were made by mixing one part of ground serpentine rock with three, parts of superphosphate. In April 1939 Messrs Grimmett, Hoy and Holford of the Department of Agriculture manufactured this material at Messrs Kempthorne, Prosser and Go's works at Wanganui for field trials. Later Mr Hoi ford on his own initiative had a commercial quantity for extensive experimental work manufactured, with the co-operation of Mr Cassels-Brown, of the Challenge Phosphate Co., Auckland.

■ From July 1939 onwards field trials were laid down all through New Zealand. They were of the usual observational topdressing type on pasture. Further trials with annual crops were carried out and good results were obtained both with yield and effect on germination—the "latter particularly. From all these trials carried out over the past two seasons results indicate that the new mixture can be recommended for use on pastures and crops over a wide range of conditions. Its value is indicated also on soils which tend to "lock up" water soluble phosphate such as superphosphate.

In conclusion it is interesting to note that dunite and serpentine exist in inexhaustible quantities in accessible localities in New Zealand and is obtained relatively cheaply so that the price of serpentine superphosphate does not differ much from superphosphate.

LIME REPORT

DISSATISFACTION AT INACTION

SUPPLYING OF MANURE!

Irritation because the recommendations of the Lime Commission had not been made operative was expressed by the Dominion Executive of the Farmers' Union, and the Executive passed a resolution pressing that these recommendations should be made operative, and that the request should be based on the present shortage of fertiliser.

Another resolution passed was that manure should be sold to farmers "sacks in," and that the farmers should have the right to supply his own bags, if he so desired.

It was a!so considered that arrangements should be made for farmers who previously bought their manure through several firms, to obtain their manure under the rationing scheme from one firm.

The difficulty in the cartage of manure experienced by those farmers whose trucks had been impressed was brought' forward, and it was resolved that such farmers should be allowed to make arrangements for the cartage of manures, etc., with their neighbours.

riving at the conclusion that silicatcs were playing a greater part