The more one learns about viticulture and winemaking, the more it becomes apparent that the actions and activities occurring in the dormant winter months is equally (if not more) important than the bustling harvest activities involved in making the wines. The numerous practices applied to the vines between the end of one harvest, and the start of the next, all directly influence the quality of grapes they will produce in future.
One of these many factors are the choices made around the planting of cover crops. Cover crops are planted for several beneficial reasons: they increase overall soil health, they help eliminate weeds, they keep the soil covered to protect it from the sun, they reduce soil compaction and improve aeration of the soil, they help optimise water usage and they greatly help reduce soil erosion.
Before we get to which cover crops are planted (and why), it is also worth noting that how we plant is also important. We are moving to reduce the practice of tillage (preparing the ground for planting through digging, overturning or stirring). Tillage can contribute to soil erosion, and you lose a lot of organic matter. It also affects water penetration, including the amount of moisture the soil can hold. We recently acquired a Piket planter – a type of planter which allows non-till planting of the cover crop seeds. You can see the Piket planter in action in our TeleVIEW video, but it basically “slices” 8 fairly shallow rows into the soil, and drops the seeds evenly into these rows, then covers the rows with soil again.
Now, on to the importance of cover crop. Planting appropriate cover crops acts as competition for weeds, competing for resources and even preventing the seeds from germinating. These crops also improve water infiltration and drainage. Bare soil can often harden into a crust, from baking under the hot sun. Covering the soil with these crops forms a protective barrier, which keeps the soil draining well and helps prevent erosion. Lastly, they are excellent to improve vine nutrition (for example, legumes can increase the carbon in the soil, and bring organic matter and nitrogen into the soils).
So, which cover crops will we be planting? Quite a few, actually. In a selected couple of blocks, we will be planting permanent cover crop for the first time. One of the blocks will be split in half: one half will have 8 rows of Dwarf Fescue (a Festuca species) planted between each row of vine, and the other half will only have 4 rows planted between each row of vine. This will allow Christo to see how much the cover crop competes with the vines, and compare the effect on the vines’ vigour. Based on that, they will choose the most suitable strategy for the rest of the blocks.
Other blocks will have forage barley planted, which is a seasonal cover crop (it’s planted, grows, then dies and needs to be replanted again the following year). Lastly, we will be planting some white clover in the extremely rocky block next to The Tatsing Room. Working the soil in that block is very difficult, but it still needs protection from the sun. The white clover will become a permanent cover crop over time – it re-establishes itself after a year, and the team will sow a small amount to supplement the growth in the first and second year, thereafter it should be fully established.
The importance of choosing the correct types of cover crop, establishing them with the best methods, and managing them carefully all contributes to the health and suitability of our Soil – one of the 8 Elements, and the very foundation of our vineyards.