Viticulture – Learning from Others

The NSW Department of Primary Industries releases a Grapevine Management Guide on an annual basis. The Grapevine Management Guide 2020-21 contains up-to-date research by the National Wine and Grape Industry Centre, which is an alliance between NSW Department of Primary Industries, the NSW Wine Industry Association, and Charles Sturt University.

One of the research reports in the Grapevine Management Guide 2020-21 concerned applying a different vine irrigation strategy to reduce weeds (“Going In and Under: A Case Study in Applying Irrigation Differently To Control Weeds” by Sam Statham from Rosnay Wines). In brief, Rosnay Organic Wines in Canowindra has been in operation since 1997. Ongoing drought, reduced water allocations and the need to manage persistent weeds organically required new thinking and a different approach. Sam Statham from Rosnay Wines had hitherto employed winter grazing with sheep and summer mowing with a swing arm mower, however, this strategy led to a proliferation of particularly stubborn perennial weeds. A knife weeder and a rotary weeder were then employed, but they led to vine damage, and affected shallow vine roots and soil fungi. Organic herbicides such as nonanoic acid (e.g. Slasher®) were trialled in conjunction with cultivation, but again the weeds were growing back and the vine vigour continued to decline.

Eventually it was realised that water and nutrients were being applied to the part of the vineyard where weeds were the most difficult to control. It was decided that it would be smarter to irrigate and fertigate away from the vines. Old dripmaster tubes were taken up and the Statham’s chose Uniram AS XR 20010 2.3L/hr @ 0.7 m spacing (20 mm tube with 1 mm wall thickness). This was installed with a Yeoman’s plough at 15 cm beneath the surface in the middle of the inter-row (1.5 m away from the vines). This was fairly efficient compared with trenching the tube in, but the Statham’s discovered that connecting the tube to the existing sub-main risers was more work than the ripping in of the tube. So, they decided to invest in a TerraTrencher™, which is a chainsaw modified into a narrow, lightweight trenching machine.

The result of this investment was better weed control, with some of the weeds under the vines dying off by mid-summer. Other weeds grew over the new irrigation tube in the middle of the row, but these were quite easily kept under control with slashing, adding some organic matter back under the vines. Another positive outcome was increased uniformity in the vine row as all the vines were receiving even amounts of irrigation and fertigation with organic nutrients. This resulted in better quality fruit and yield in the 2020 vintage compared with previous vintages.

For further information on this case study contact Sam Statham at Rosnay Wines on info@rosnay.com.au.

• Topics:

• Wine / Viticulture
• Rural Roundup