MINERALS FOR PASTURES

Press, Volume LXXXVI, Issue 26117, 20 May 1950, Page 5

MINERALS FOR PASTURES

Mr W. B. Trotter’s Address

BIG GATHERING AT OHOKA

Striking evidence of the interest farmers are taking in mineral topdressing of pastures was provided on Tuesday evening when at an open meeting called by the Ohoka and Districts branch of Federated Farmers, more than 140 farmers turned out to listen to an address by Mr W. B. Trotter, of Fairlie. whose work with copper sulphate has attracted such wide interest. Beside local men, visitors were present from the Oxford, Cust, Fernside, Woodend. Amberley, Sefton, Waimairi, and Ashburton districts. Mr Trotter was given a most attentive hearing, and was warmly thanked at the end of the evening. It was substantially! the largest meeting the Ohoka branch has ever held, and the branch is noted for the excellent attendances at its open meetings.

Mr Trotter opened by saying that not much was known about the effects of minerals on the soil, and the subject was important enough to warrant immediate and thorough investigation. He suggested that the statutory boards’ pool funds would be very unlikely to be paid out to individual farmers, and said that the Fairlie farmers had asked that part of these funds already set aside for research should be spent -in investigating minerals and their effects upon pasture.

After describing the results he and some of his neighbours had obtained with the use of copper sulphate as a top-dressing, Mr Trotter said that copper was a typical example of the state of knowledge of the minerals important to pasture growth. Something was known about copper, for instance that it was necessary for the formation of bone and blood in all animals, but knowledge was not 100 per cent, complete by any means. “Some people may think that an increase of 70 per cent, in production from pasture treated with a mere 51b of bluestone is ridiculous,” he said, “but Lincoln College got somewhat similar results on land near Christchurch. After treatment with copper, this land produced an extra 14 tons of carrots to the aerie. I think it was unfortunate that the college did not carry on and analyse the carrots to see what extra elements there were in the treated carrots. It appears that the copper must have acted as a catalyst and either built up the strength of the plants so that they could absorb the extra minerals, or acted on the soil and made minerals available that were previously locked up.” “No Half-way House” Mr Trotter gave figures of the copper analyses of pasture in the Fairlie district, on his farm and on others, which suggested that the line of demarcation between a sufficiency and a deficiency of copper was very fine. “My argument with the Department of Agriculture is that they will not recognise any half-way house,” said Mr Trotter. “It must be either black or white; either there is a deficiency or there is not a deficiency. To my mind it is a lot more dangerous to have a deficiency which is just on the borderline than it is to have a bad deficiency. If there is a serious deficiency, stock will show it by dying, qr becoming very sick, and the deficiency is easy enough to recognise and deal with. But if the deficiency is small, all you know is that the stock are not just right, but you can’t pick why.” Deaths last year among his 1500 ewes numbered 35, said Mr Trolter. Of these, five died from misadventure, and the other 30 about equally either from bearing trouble, or what was diagnosed as milk fever. He believed the milk fever was more probably grass staggers, because the ewes responded well to molasses, which suggested that the deficiency was magneslunj. The bearing trouble he had was also probably a deficiency trouble. From his line of ewes, a mob was run off and sent down to a farm on the Plains near Ealing. These ewes were a straight run off from the rest of the mob, and actually two of them developed bearing trouble before they left Fairlie and could not be sent. The man to whom they were sent had ’ never seen bearing trouble and was still waiting to find out what it was, because none of the ewes sent to the plains developed bearing trouble, though it continued to crop up in the rest of the flock at Fairlie. “It seems to me that the trouble is due to the country, and to some mineral being present in the Plains pasture which is not present at Fairlie,’’ he said. Mr Trotter said that he had asked Dr. I. G. Cunningham, of Wallaceville, what the mineral composition of good pasture was, but Dr. Cunningham said that while something was \known about four minerals, and a little was known about four more, the total mineral composition was not known. “Sheep and worms have always gone together,” said Mr Trotter, “and so wherever you have sheep you will always find worms, but I think that you would find that before worms can get seriously to work, you- have got to have stock in a certain condition of health. Healthy stock are never affected. Therefore I tried to interest Dr. Cunningham in taking total analyses of pastures from which healthy stock were coming, on different classes of land, with the idea of having a standard analysis of pasture worked out so that a farmer could have an analysis of his pasture made and see where he stood. Dr. Cunningham simply said that his department was up to its eyes in work, and did not have the staff, so work on pasture analysis would have to wait. He suggested it might have to wait 10 years. I have got the idea that that is too long.” Mineral Balance A chart showing the relative importance in soils of 17 different mineral elements was displayed by Mr Trotter, who developed the theme that these minerals were in balance in good soils. The balance he claimed, could be upset if extra quantities of one or other of these elements were added, as such elements as calcium, phosphorus, and nitrogen were added as part of normal farming practice. The addition of extra quantities would obviously destroy the balance, and could result in other minerals and trace elements being exhausted by the additional plant growth that followed, or being locked up in a form not available to plants. This was where a standard pasture analysis would be invaluable. A farmer could have his pasture analysed to see if the minerals were in balance, and add what was needed to restore the balance. “If we add all the minerals and keep the proper balance,” he said, “it is very hard to see what limit there would be to production. We have the rain and sunshine that are all that is needed to make growth.” Mr Trotter predicted that mineral deficiencies similar to those found at Fairlie would surely come elsewhere in Canterbury. It might be that the minerals were in better balance in the plains, but under modern pasture methods, there would certainly sooner or later be trouble. His own land was valued at £l4 10s an acre, yet its production amounted to £22 an acre last year. It was second-class land, but much of the second-class land of this country started with the great advantage of an assured rainfall. Irrigated light land would come into its own when minerals were better understood. On light land under water, the effects on stock health would become quickly apparent. Mr Trotter concluded by discussing the possibility of dangef* from applying too much copper to pasture. Dr. Cunningham told him that there would be no danger at all if 51b were spread on every acre in New Zealand. Not all land was copper deficient, so any farmer trying copper would be quite safe to put on 51b. If he got no response from that amount, he should not put on any more. If there was a response, more could be applied. “I can’t speak for North Canterbury,” j said Mr Trotter, “but the evidence for copper in the Eairlie district is so good j

that no departmental officer can argue against it. We have the figures now. and after all, figures are what interest us as farmers.”