Tilling, fertilization and cover crops

Now that winter is over, I’d like to share a few thoughts on soil maintenance. It is difficult to understate the importance of the soil, as it sustains everything we grow. 
Since last year we’ve been ploughing the soil between the vines more and more as a means to aerate the soil and control weeds. Aeration is normally taken care of by worms and insects living in the soils and digging their way through them, but compactation by tractor wheels and a lack of plants to sustain soil life have made it necessary to plough. In order not to overdo it, we started by ploughing alternate rows.

The lack of plants to sustain soil life basically means the lack of weeds: their roots can help to break up the soil and feed insects and worms living in the soil. We’ve started to experiment with cover crops to observe their effect. The goal is to accumulate biomass in the soil, while at the same time trying not to have these crops compete to hard with the vines for water and nutrients. This means we favor plants that grow in winter, seed and then dry up starting in spring. Mustard is one such crop and has bright yellow flowers before the vines start budding.

To avoid competition for nutrients it's best to fertilize cover crops while you sow them. For ease of application and their low cost we use chemical fertilizers. There’s nothing wrong with them, as long as you don’t abuse. In the end, the cover crops, as the decay, will return these and other nutrients to the soil, which will favor the vines in the long run.

Otherwise, we use stable manure (from cows and horses) as fertilizer, which has the added benefits of adding organic matter as well as micronutrients to the soil, but is harder to obtain and handle, as quantities are big.

The only other (micro) nutrient we’ll be using this year is zinc, as the level in both soil and plants last year proved to be low. The plants only use minute quantities of this mineral, but the lack of it causes stunted growth and shatter of berries.

Alternatively, after ploughing, native vegetation starts to grow, and seems almost as beneficial for the soil as cover crops. Grasses and wild flowers seem to be the mainstay.

We’d like to see some clover or leguminous plants as well, so next year we’ll be sowing some of those, apart from the mustard seed. Other cover crops we tried were less of a success. Oats and vetch were mostly eaten by birds early in winter. Growing a mixture of grasses gave almost the same result as the grasses that grow here naturally, so that was a bit of a waste of money!

All in all, weed control is getting easier, as the hardest ones to control are being outgrown by these smaller ones in winter, and we’ve been controlling the former as early as we can, to avoid propagation.

Pruning has finished by now, and we’re busy tying down the last canes before budburst occurs. We just had some heavy frost that badly affected fruit growers all over the central part of Chile. Fortunately our vines bud a little later than most as this area is fairly cool, so we were not affected at all. Maybe an indication we’re growing the right crop in the right place?

And for those of you trying to find the winery, the gate is not green any more but now painted in “Lagar Red,” a color taken from the wall painting in our tasting room and now very distinctively ours!

The Chilean flag in the background is mandatory, to celebrate Chilean independence (18 September).