Six Ewes To Acre On Light Land?

Press, Volume CIII, Issue 30610, 28 November 1964, Page 9

Six Ewes To Acre On Light Land?

Six ewes to the acre on light land! It is not a dream but is actually being envisaged by Mr C. E. Iversen, reader in agronomy at Lincoln College, as a consequence of his finding reported to last week’s college field day that when grazed at the hay stage pure lucerne is capable of producing 90001 b of dry matter to the acre on light land.

There are some problems, however, and this is mainly a matter of modifying the management system to fit in with the special demands or requirements of the plant, while at the same time providing the year round requirements of stock. Dr. J. D. Stewart, acting head of the farm management department at the college, said this week that the two important things that they would have to examine was the possibility of later lambing to fit in with the mid-September start of growth of lucerne in the spring and a rotational grazing system to secure the best possible production from the lucerne.

Mr Iversen said this week that whatever number of stock was carried on light land there was always a shortage of feed and cutting down stock numbers was not the answer. In 1957 he had suggested in a bulletin that this land could carry two ewes to the acre. He had subsequently revised it to three and this year in a repeat issue of the bulletin he had moved the figure up to four ewes, but now he considered even this out of date and believed that the potential was six ewe equivalents. Light land farmers should not faint at the thought, said Mr Iversen. They should think of the Taranaki miracle of two cows to the acre. Here Dr. Stewart referred to the case of the man who had started there three years ago with 180 cows on 250 acres. In his second year he put on 250 cows and this year 360, which he would have actually

raised to 400 head had he had the money to buy them. This was done without growing any crops, no pasture renewal, no silage and only 10 bales of hay per cow for the winter. The answer was fertiliser and more stock. What did he mean by saying that the light land farmer was always short of feed regardless of ewe numbers? Mr Iversen said that light land pastures with subterranean clover as their base gave 70 per cent of their yield in the spring. If the farmer did not have enough stock he could not get all this feed eaten. Then hair grass, goose grass, sweet vernal, browntop and danthonia got a foothold. In the following autumn the annual subterranean clover plants were unable to germin,ate because of lack of moist-

ure which was stolen by the grasses. Thus there was simply no subterranean clover, no nitrogen and no production.

Overseas it would be said, make hay and silage out of spring surplus production. That was all right up to a point, but hay and silage were less than 50 per cent efficient. Sir Bruce Levy had told the grassland world: “It must be eaten in situ,” and experience in Taranaki had proved him absolutely correct. The clue to the talk of six ewes to the acre was lucerne and as Mr E. C. Topp, of Waipara, said, “lucerne and more lucerne.” It had been de-

scribed as the greatest.” With dry matter production of 90001 b per acre it was theoretically possible to carry six ewes to the acre on this light land. The North Island had 55m ewe equivalents and the South Island 25m, and that was why there was a drift to the north. If it was possible to raise the carrying capacity of the drier land of the South Island to six ewes the present 25m ewe equivalents could well become 40m and some of the population would be drifting back. The recipe was that more lucerne had to be grown and it must be used properly. And that quality feed could produce liveweight gains far beyond the wildest dreams of the animal nutritionist. For example, lambs weaned at seven weeks of age out of Border Corriedale cross ewes by Dorset Down rams had put on 421 b of liveweight in 42 days on pure lucerne stocked at 40 to two acres on the pure pasture specise trial at the colleged. They had gained 181 b in the first 21 days and 241 b in the next 21 days. To get the best production from lucerne Dr. Stewart said it had to be grazed or cut when it was 10 per cent in flower, and this Mr Iversen interposed was also the time

when it was most edible. The problem, said Dr. Stewart, was to reconcile this requirement of the plant with the requirement of the stock. This year, for instance, it had been necessary to graze the lucerne intensely for three months on end.

If there was only a moderate area of lucerne, such as they had at Ashley Dene at present, there was not much of a lambing feed problem. Stirred up subterranean clover and Italian ryegrass provided the later winter and early spring greenfeed, there were turnips and hay for winter and if there was no spring drought it was possible to graze some of the lucerne in the spring and also make hay out of some. In a good spring all the hay that was possible should be made and enough for a two years’ supply should be stored under cover. He did not think that a farm management system should be designed specifically to deal with spring droughts which were relatively rare. There was a different position where two-thirds, or three-quarters of the whole farm was in lucerne —a plant that did not grow feed in the winter and in the early spring up to mid-September. The problem where there were maximum areas of lucerne was to balance feed supplies in July, August and -part of September. This might be overcome by oversowing lucerne, which was running out, in the autumn with Italian ryegrass or oats to provide greenfeed. The other angle of approach was in the time of lambing. Efficient light land management was regarded as early lambing, early drafting and early weaning, and this was undoubtedly the procedure under the conventional system, but the maximum areas in lucerne it might be necessary to think of later lambing to fit in better with feed requirements. Lambing a month later might fit into this pattern.

How should lucerne be handled after September 15? The need here was to devise a grazing system that would permit the conversion of the maximum level of production into meat. Because lucerne was at the most edible stage when it was grazed when it was a tenth in flower, it was not known whether there would be any adverse effects on growth rate from rotational grazing.

Dr. Stewart said he regarded the development of a management system for these sort of conditions as the next stage in light land management. Use of new grass killing sprays would mean that renewals of stands would not have to be made so frequently.