When farms are converted to pivot irrigation the first thing that has to happen is that all the shelter trees have to be removed. Trees and pivot irrigators do not get on well together. The result of course is that the pivot irrigated areas are not sheltered any more. In Canterbury this means exposure to hot drying Norwest winds and also cold southerlies. In Southland it means exposure to very cold southerlies. The southerlies are known to decrease grass production by at least 10%, while the hot Norwesters can have a more dramatic impact on grass production. This also means that a significant amount of irrigation water is simply lost to evaporation.
Professor Steve Wratten of Lincoln University’s Bio-Protection Research Centre and (then) PhD student (now Dr) Chris Littlejohn investigated the possibility of using Miscanthus on pivot irrigated dairy farms in Canterbury to provide the missing shelter. Chris’s research was carried out over several years, funded mostly by Westland Milk Products Ltd and partly by Dairy NZ. It involved establishing Miscanthus in strips wide enough to be harvestable – 6 or 7 m – and then assessing the impact of these strips on grass production. It was quickly established that the Miscanthus had no negative effect on the irrigators and the irrigators had no negative effect on the Miscanthus. In fact, the Miscanthus loved being regularly watered and grew extremely well.
In addition the pasture benefitted from the shelter that the Miscanthus provided so they ended up with what could be regarded as a symbiotic relationship. Although the Miscanthus took up what some farmers would regard as a significant area of the farm, the increase in grass growth in the sheltered areas more than made up for the area occupied by the Miscanthus. So farm production in effect was increased.
Under Prof Wratten’s direction, the Miscanthus was evaluated as a possible suitable environment for bumblebee nests. Lincoln set up what they called bumblebee motels and the insects thrived. As a result the population of bumblebees available for pollinating, particularly red clover, was enhanced significantly. On top of that, it was established that the population of indigenous skinks also increased significantly, presumably because of the ability to use the Miscanthus as habitat, no doubt also appreciating the shelter benefits.
For 100 m from the shelterbelts, soil moisture was maintained at higher levels than in the unsheltered areas. The population of earthworms in these sheltered areas was also higher. You can read one of the published papers on the subject in this link.
TV3 did a summary of the whole Miscanthus shelter picture some years ago and there was an excellent follow-up to that last year, fronted again by Prof Wratten. You can view this at: www.ruraldelivery.net.nz/stories/Miscanthus-Grass Those with an interest in environmentally friendly commercially focused farm development should provide him with funds for more practical research.
Some extra information from this research came by accident. Electric fence failures resulted in the cows getting into some of the Miscanthus stands and eating the leaves. They left the stems which provide much of what you really need for good shelter and the Miscanthus regrew without any trouble.
But the really telling occurrence was when the irrigator was blown over in a serious Canterbury storm. The damaged irrigator was partly in one of the Miscanthus shelter strips. Effectively, the above ground Miscanthus was eliminated in places and contractors’ vehicles were driven repeatedly over the Miscanthus strips. But when the irrigator had been repaired and the fences re-erected, the Miscanthus came away again just as well as before. It showed what a hardy plant Miscanthus really is – as Miscanthus New Zealand Limited (MNZ) has been telling people for quite some time.
Since then, MNZ has supplied Miscanthus plantlets to several different farmers – until now, mostly in the South Island – for establishing farm shelter. They all say that they want to minimise the area taken up by the Miscanthus – and hence the width of the shelter strips – which is not unexpected. But once they see the value that is added to their farms they will be looking to expand their establishment of shelter strips to a more sensible width. Increased shelter means increased grass growth with less irrigation needed, so Miscanthus shelter reduces costs while adding to the net return for the farm.
North Island farmers are now also starting to understand the benefits that they can gain by using Miscanthus for farm shelter, particularly on pivot irrigated blocks. They too have periods with hot drying winds and cold southerlies at times so the benefits for them are the same, albeit perhaps not as much as for their South Island colleagues. This week, one farmer has told MNZ that he plans to plant Miscanthus on one of his farm boundaries in Spring 2019, as well as planting several hectares for production.
So, if you have a farm that needs shelter – and what farm would not benefit from more shelter – you should get in touch with MNZ now and get your order in for the Miscanthus that you will want MNZ to plant for you this coming Spring.