Margaret River Vineyard Report Winter 2013
The winter is now with us and recent rainfall and some cooler than average temperatures has the vines senescing and preparing for the dormancy that occurs through winter. When driving through the Margaret River region we now see sheep grazing in the vineyards and with the ewes come the new born lambs, all timed in management and nature to coincide with using the grasses in the vineyards and some weed control management. The lambs create significant interest from tourists and backpackers and many times we see carloads stopped on the side of the road watching the birth of a lamb or taking photos of lambs frolicking around the vines…. We did have one Korean backpacker girl working with us in the vineyard that we nick named Mary for obvious reasons; the lambs kept chasing her around. The more she ran the more lambs chased her! Of course vineyard workers have a great sense of humor and it wasn’t long before there were some interesting comments. The better ones were; Mary had a little lamb and tied it to a pylon, 10,000 volts went through the thing and turned its wool to nylon.
And; Mary had a little lamb her friend he shot it dead, and now she comes to work with it between two slices of bread! Thankfully, Mary saw the funny side of our Aussie wit and Korean and Australian relations are preserved.
….Ok back to work!
Those vineyards in Margaret River that have planted cover crops, will not have sheep and lambs but now have the indication of seed establishment and we can see some fantastic germination of oats, rye, lupins and pasture mix out in the vineyards. Shrewd viticulturists have already completed soil samples and analysed to determine the soil mineral wealth for the cover crop and future vine requirements. Where necessary we have made some applications of the correct fertilizer to improve availability within the soil to the plants. Importantly, the cover crops that are grown through this winter and spring will eventually mulch in the soil and become the potential nutrition for vines and future cover crops… all part of the nutrient cycle.
During winter, grapevines senesce and therefore lose the leaf and cease taking up minerals and nutrients from the soil. We generally have very wet winters in Margaret River (expect 750 – 1200mm annually) and the outcome can be leaching of mineral wealth from the soil. This leaching or loss of soil minerals has a compounding effect not only on future profitability but also on the environment. The use of winter crops to take up minerals that would otherwise be lost through leaching is very important. These minerals are stored in plant tissue and are released when decomposition occurs. This is a natural process of the plant dying and soil microbiological activity. We recognize that half of the plant biomass is root system and that this is already incorporated in the soil, this is important as we may actually achieve much better change to soil structure and mineral wealth by having deep rooting and volumous root systems. The concept is to select a plant species that is suitable for the environment and then support healthy plant growth (the bigger the root mass the better the end result). The end result should be better nutrient/mineral uptake and then excellent opportunities from future biologic and organic benefits.
The biology of decomposition is usually understood as the process of composting. Composting is generally achieved with bacterial digestion of organic matter and as a result of this process minerals are released and other beneficial organic compounds formed. What is not widely understood is that soil fungal pathogens also use organic matter and these fungal pathogens bring a symbiotic relationship with plants that improves soil and plant health. Fungal pathogens such as Mycorrhiza are being better understood for the benefits that are seen with general plant health and the ability to source out minerals that would not be otherwise available to plants. We would have trouble explaining these benefits in the short space available but I would suggest that the word “Glomalin” is worthy of research if you are interested in knowing more about soil and plant health and the benefits mycorrhizal fungi bring.
Another benefit of having established cover crops in the vineyard is that it allows the identification of mineral deficiency through observation. We regularly test soils for mineral availability and other indicative attributes. Not always are the results that we see in analysis similar to what we see in plant health. Every year winter is different, rainfall events vary in volume and timing, temperature can be hotter or cooler and soil temperature will change. The biologic activity in soil will be variable and the complex soil chemistry with its cation and anion exchange (effecting nutrient availability to the plant root system) will challenge us. As a result of seasonal variation, plant species will respond differently and we need to take this into consideration when we assess the needs of grapevines going forward. For this we look at plant growth and also deficiency symptoms of winter and spring pasture and vine growth and then make adjustments to the mineral requirements of the plants. We use tools such as soil and leaf analysis to help support what we observe. It probably sounds complex but is simply an extension of what would normally be expected for routine plant performance analysis. Simply, if the winter cover crop is performing well, then we could expect the summer grapevine performance to be acceptable for quality wine production! This is a constant cycle of improvement within the vineyard and meeting the challenge of making the best possible wine out of Margaret River vineyards.
With the soils in good shape and cover crops growing it is then time to turn attention to pruning. Time to go into the shed and find the pruning shears, sharpen the blades and load up the i-phone with some music and podcasts for the next couple of months listening pleasure!
Pruning is the focus within Margaret River vineyards now and will continue into August until budburst occurs. We can see individuals and teams out in the cold and rain toiling away. Importantly, pruning sets the vines crop for the coming vintage and much reflection on the success of the previous growing period and wine quality as well as consideration for future crop requirements will be managed…. and then the cuts made.
Happy pruning everyone!
Contributed by Bruce Pearse, Viticulturist
Margaret River Discovery Tours
Sean Blocksidge is the owner operator of the Margaret River Discovery Company, an avid photographer, blogger and South West WA ambassador. In 2010 he won Western Australian Guide of the Year and his tours have been rated the #1 thing to do in Australia on the Tripadvisor website for the past two years.