Nursery takes initiative with the Sustainable Winegrowers (NZ) programme

15 January, 2008

Since the inception of the Sustainable Winegrowers New Zealand (SWNZ) programme in 1995, membership has swelled with 510 vineyards and 64 wineries currently accredited. A further 66 vineyards and seven wineries have joined the programme and will be audited in 2008. Sustainable Winegrowers is an industry initiative directed by New Zealand Winegrowers, to provide a framework for best viticulture and winemaking practices that protect the environment (www.nzwine.com/swnz). The programme was initially introduced for vineyards in 1995, and then adapted in 2002 for wineries. In 2006 an initiative was drawn up to include grapevine nurseries. Corbans Viticulture is the first grape propagation nursery in New Zealand to be accredited as sustainable by Sustainable Winegrowers as of December 2007.

The Sustainable Winegrowers New Zealand (SWNZ) programme

An information manual and an electronic scorecard are provided by Sustainable Winegrowers. The scorecard is completed over a 12 month period ending on the 30th of June each year. The scorecard rates the sustainability of practices such as water, fertiliser and agrichemical usage according to a points system. It also assesses pest and disease monitoring, soil and nutrient testing, calibration of spray equipment, biodiversity, attendance at technical workshops and ongoing staff training. The scorecard is submitted with an electronic SprayLog diary of agrichemical use, a property spray plan (software developed by HortPlus, HortResearch and Crop & Food Crown Research Institutes) and records of soil and foliar nutrient testing, fertiliser inputs, irrigation records and Growsafe™ and Approved Handlers certificates. New members are audited by an independent agency upon submission of their first scorecard. The auditing process includes a site visit by the auditors.

Adapting the scorecard for nurseries

Scorecard categories for vineyards are also applicable to the nursery situation, with the exception being practices specifically targeted at grape production such as leaf removal and control of botrytis. There is a greater emphasis in the nursery on the control of Powdery and Downy mildew. Young vines are more susceptible to these diseases and trunk and root diseases such as Petri disease, Botryosphaeria, Blackfoot and Crown gall can be transmitted to vineyards if not controlled effectively in the nursery. Further categories that are likely to be added to the grapevine nursery scorecard include the use of green waste generated during grafting, trimming and grading of vines prior to sale, the recycling of water during vine washing, efficient energy usage, rootstock management and the control of fungal diseases in material used for grafting. Testing of grafting material for viral disease and the setting of quality standards for grafted grapevines is covered in the recently developed Grafted Grapevine Standard (GGS), another New Zealand Winegrowers initiative.

In addition Corbans Viticulture gained GGS accreditation in 2007 (one of the first grapevine nurseries in New Zealand to do so) and views the two programmes as complementary. The focus of the GGS is on the quality of the final product- grafted grapevines, as well as traceability of grafting material to its origin, viral testing and trueness of type. The SWNZ programme key focus is the use of regular and timely monitoring of pests and diseases, and soil and foliar testing to determine agrichemical usage, the recycling of green waste and water, the control of fungal diseases in such a way as to reduce likelihood of agrichemical resistance and to increase the biodiversity in the soil, plant and animal life in the vineyard.

Changes made in nursery practices as a result of the SWNZ programme

As a result of joining the SWNZ programme, there have been several changes in nursery operations at Corbans Viticulture. There is a greater emphasis on testing and monitoring to determine applications of fertilisers, likewise regular monitoring and reporting of pests and diseases has resulted in a reduction in use of herbicides, fungicides and pesticides.

Nursery and rootstock blocks are routinely tested for soil nutrient availability (Reams test, International AgLabs) as well as the total nutrient pool (basic soil test and organic soil profile, Hill Laboratories) before fertilisers are formulated and applied. Soil test results are imported into Integrape™ software (www.agconsult.co.nz) and historical changes in nutrient levels over several years are used to determine the efficacy of fertiliser applications and fallowing programmes. Monitoring sheets have been developed by Corbans Viticulture specifically for nursery and rootstock blocks and records are kept for the annual scorecard submission.

Active compost, compost tea, vermicast and biological formulations are added to the soil to build up the soil biodiversity and enhance nutrient cycling. During flowering, leaf and petiole tests as carried out on rootstock and nursery blocks to determine appropriate foliar feeds during the summer. Leaf and petiole brix tests are taken during the growing season to monitor sugar and soluble solid production. Soil organic matter, soil structure and soil biology (bacteria, fungi, protozoa) and mycorrhizal colonisation of the roots are also tested by Soil Foodweb Institute (NZ) Ltd and Biocult Laboratory respectively.

The Research & Innovation programme at Corbans Viticulture have trialled a number of alternatives to agrichemicals to enhance soil structure and biodiversity and plant growth. These include use of hot water treatment alone and in conjunction with formulations such as compost tea, active compost, Bioplex soil drench, Solid Rok, Vitazyme and mycorrhizal enhancers (Mycorrcin, Mycomax, Myco-gro), Superzyme containing Trichoderma, Bacillus and Pseudomonas species. Lincoln University in conjunction with Corbans Viticulture is currently undertaking field trials to test the effectiveness of hot water treatment, biological formulations and fallow crops against blackfoot disease.

Conclusion

Since joining the SWNZ and GGS programmes, Corbans Viticulture have seen a significant improvement in their production systems, resulting in an overall improvement in vine quality, larger root and shoot growth in young vines, better yields in the nursery, and improved soil structure and biodiversity. Client feedback on vine quality has been very positive to date. The increase in costs associated with more comprehensive testing and monitoring programmes have been offset by reduction in agrichemical use and increased yields in the nursery. Future challenges to improve sustainability in the nursery will include the use of new technology for weed control, control of fungal and bacterial diseases, more efficient energy usage and the recycling of green waste and water.