Lucerne Grazing Scheme

Press, Volume CIX, Issue 32303, 22 May 1970, Page 7

Lucerne Grazing Scheme

As a result of grazing management studies of lucerne, Professor K. F. O’Connor, now professor of range management at Lincoln College and director of the Tussock Grasslands and Mountain Lands Institute, submitted to this week’s conference of the New Zealand Grassland Association a procedure for lucerne management under grazing by sheep. While these recommendations might be refined by further research into the intricacies of lucerne regrowth, Professor O’Connor, who was reporting on work he did when he was officer-in-charge of the Lincoln sub-station of the Grasslands Division of the Department of Scientific and Industrial Research, said that they were: (a) A four-paddock rotation system taking about eight weeks to complete the cycle. (b) Sufficient numbers of the right kind of stock to consume the feed offered at, the time. (c) Supplementary break; fences to shorten the graz- , ing duration during critical shortages, such as in winter and in summer | drought. Answering a question, Professor O’Connor said he regarded lucerne as a valuable winter greenfeed which he proposed should be grazed about one week in six or eight weeks at that time of the year, so that growth on it was used, and the stand was left in excellent order with weeds having been well controlled in preparation for the spring growth. Where the plant was growing in the autumn under conditions of autumn rainfall he proposed that similar grazing treatment should be applied as in. the spring—two weeks’ grazing and six weeks’ spelling—but under dry autumn conditions it would be necessary to shorten the grazing period as was the case in a summer drought

"Lucerne management for sheep grazing requires intelligent understanding of plant and animal behaviour," Professor O'Connor told the conference, “Because lucerne changes in feed quality during spelling, one cannot expect a manager to treat it in the interests of the plant alone. “Also, because lucerne changes in feed quality during grazing one cannot expect animals to treat it except in their own interests. A new compromise must be reached. Lucerne’s needs for relatively long spells between grazings (a month or more) should not be compromised. . . .” Presenting a paper on the growth of lucerne after defoliation, Professor R. H. M. Langer, professor of plant science at Lincoln College, with whom was associated J. M. Keoghan, said one could argue that leaving a tall stubble might be beneficial if it provided plenty of sites for the formation of auxiliary shoots. However, even this possibility did not appear to be of any great consequence in a sward in which the major part of the recovery growth

seemed to come from basal shoots arising from the crown region. Naturally there could be genetic differences in this respect, especially in prostrate types of lucerne. However, in upright lucernes few, if any. advantages accrued from raising the cutting height above 5 centimetres in the hope of encouraging more rapid recovery. If a lucerne stand had been mismanaged by repeated cutting at immature stages of growth. the remedy lay in increasing the length of the recovery period until new basal buds were ready to take over the growth of the plant after defoliation. In a joint paper Drs R. W. Bailey and R. M. Allison, of the Applied Biochemistry Division of the D.5.1.R., and Professor O’Connor, said that lucerne in Canterbury yielded large amounts of readily available carbohydrate energy as well as fibre, and large amounts of protein. Efficient use of this energy could well incorporate a siphoning off of large amounts of the protein for direct human consumption.