I know this is a similar photo as above but I've been looking at it for a while and realize some of you might not know what's going on up there. The green growth in between the vines is the winter cover crop. There are a number of reasons we plant cover crops.
By choosing your mix of what you plant you can dial in your soils so that you do not have to rely on adding fertilizer to keep the vines healthy. Healthy soil = healthy vines. And fewer external inputs to the vineyard hopefully means the true character of the vineyard will shine through in the finished wines.
In this picture you can see that the crop alternates every other row. Each mix has a specific goal. The rows where you can see more defined lines are the rows that have legumes in the mix. These fix nitrogen in the soil and further add nutrients when you mow them and incorporate them into the soil. The more uniform rows are grasses to prevent erosion and then they will mow this row. After mowing that is the row that will carry most of the tractor traffic keeping down dust. Next year we'll switch the rows so one will get the rehab and the other will be grasses.