FORAGE AND ARABLE
New research proves deferred grazing works | The research indicated that deferred grazing has several effects that collectively improve pasture performance.
The benefits of deferred grazing observed by a group of hill-country farmers have been scientifically proven and quantified, with some impressive results. When the farmers deferred grazing by dropping some paddocks out of rotation from mid-spring to late summer or early autumn, they saw improved overall pasture quality and increased production from the deferred area the following year. They also gained a valuable source of late summer feed. None of these benefits had been scientifically proven or quantified, however, so the farmers and researchers initiated a 3-year Sustainable Farming Fund project to do just that. The project compared deferred grazing and rotational grazing on three different sheep and beef hill-country farms: two summer wet farms in the Bay of Plenty and one summer dry north-western Waikato farm. In terms of livestock performance and farm profitability, Farmax modelling on the summer dry farm showed an 8 percent increase in total farm and per hectare gross margins when 15 percent of the farm was deferred.
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The project’s results indicate that deferred grazing has several effects that collectively improve pasture performance. First, it allows ryegrass and other desirable species to produce new tillers and to reseed and produce new plants the following autumn. This increases tiller density of desirable pasture species and can increase pasture persistence. When grazing was deferred, the amount of mineral nitrogen potentially available for plant uptake was also significantly higher, probably due to higher levels of litter content enhancing mineralisation of organic matter. Deferred grazing also reduced weed content and facial eczema spore counts and increased topsoil moisture at the summer dry site. Although the deferred grazing treatment produced a similar amount of growth to the grazed treatment, it altered the timing of feed supply and created a feed wedge at the end of summer or early autumn. This is particularly useful in drought years. The pasture nutritive value in the deferred paddocks declined during the deferred period but pastures rapidly recovered so it was not enough to
offset the overall farm-scale profitability of deferred grazing. Deferred grazing also helps to maintain overall pasture quality. As some paddocks are removed from grazing, stocking rate increases elsewhere and the spring feed surplus is better used and pasture quality maintained. Research has also shown that when deferred pastures are grazed in late autumn, the content of clover can increase. An easy-to-use handbook for farmers or consultants with a summary of the project’s results and instructions on implementing deferred grazing is available at beeflambnz.com/news-views/ deferred-grazing-handbook-released. The project was funded by the Ministry for Primary Industries’ Sustainable Farming Fund with co-funding and support from Ballance Agri-Nutrients, Beef + Lamb New Zealand, Environment Bay of Plenty, Waikato Regional Council, Plant & Food Research and AgResearch. For more information, contact your Ballance Nutrient Specialist, your Farmlands Technical Field Officer or the friendly team at your local Farmlands store. Article supplied by Ballance Agri-Nutrients
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