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Beyond the Bale : December 2012
24 24 September 2010 Beyond the Bale Fast Facts l EverGraze Supporting Site host Rick Robertson from East Gippsland, Victoria has used saltbush to transform his saline flats to a productive area, ideal for lambing ewes. l Shrub hedgerows have been successfully used to produce feed and shelter in otherwise unproductive, saline soils. l Wind chill measurements taken at lambing revealed the hedgerows reduced the number of times the wind chill reached high-risk levels. December 2012 Beyond the Bale 24 on-Farm establishing saltbush In an effort to improve low-lying unproductive saline land and provide lambing shelter, Victorian woolgrower Rick Robertson has established saltbush. During spring 2004, Rick chose a 16ha trial site on the lakeside flats, less than 1500 metres from the shores of Lake Victoria. This site was split into a 10ha treatment block and a 6ha control block. The control block was covered in mainly native grasses, tussocks and weeds and was left untouched. The treatment block was disced and cross ripped. Dolomite was applied at a rate of one tonne per hectare and incorporated with a second cultivation. To maximise shelter for lambs, the saltbush was established as hedgerow windbreaks, aligned north to south, with 4.5 metre spacing between the rows. Six hectares of the treatment block were sown to Atriplex nummularis (oldman saltbush), Atriplex nummularis cv De Kock (De Kock) and Rhagodia candolleana (seaberry saltbush), at a rate of 2700 seedlings per hectare, planted with a lettuce planter hired from a local vegetable grower, and costing $1000/ha. The remaining four hectares of the treatment block were sown with oldman saltbush seed, at a cost of $150/ha for seed, using a borrowed homemade saltbush seeder. Both the seeds and seedlings established well, and while the seedlings were faster to establish, there was little difference between the two techniques after two years. The plants were left untouched for the first 12 months, reaching an average height of one metre. The plants were dense and multi-stemmed, producing a significant quantity of leaf material. grazing beneFits The saltbush certainly achieved the aim of bringing a previously unproductive site back into production, providing significantly more grazing days than the neighbouring, unimproved control block. “ We found the adult sheep adapted quickly to saltbush as a feed source and that they could maintain their body condition during general feed shortages. This reduced the time and money we spent on supplementary feeding. Lambs were more difficult to introduce onto the saltbush, as they preferred the grasses in the inter-row areas,” Rick explained. “ The result was that the 10ha of saltbush improved the overall carrying capacity of the farm, adding value to it as an asset.” combating wind chill To determine the protective value of the saltbush, as part of an EverGraze Supporting Site, Rick decided to carry out a simple demonstration using two flocks of lambing ewes to compare weaning percentages on the saltbush paddocks with the unimproved site. The Supporting Site was complemented by concurrent trials performed by Darren Hickey, Department of Primary Industries, Victoria, who used equipment to measure the difference in wind chill between saltbush hedgerows and unsheltered areas. The results for the saltbush hedgerows were again encouraging, and showed that the hedgerows were effective in reducing the number of wind chill events and chill days during lambing periods (see Table 1 below). “ The hedgerows reduced the occurrence of wind chill events by up to 90 per cent compared with the open paddocks,” Rick said, “although this did not translate into significant marking rate increases in the study years, which had few severe wind chill days.” More information: The full case study is available on the EverGraze website www.evergraze.com.au east gippsland merino producer rick robertson with saltbush hedgerows at the bengworden evergraze supporting site. Trading low productivity for high protection TABLE 1. Number of wind chill events (where heat loss exceeded 1000kJ/m2/hour) 2010 2011 Sheltered, hedgerow site (best across sites) 330 640 Open, unprotected site 3292 1615 Percentage reduction 90% 60%