February 2011 Douro Insider

February got off to a fine start, with the first week or so crisp and beautifully bright, albeit with frosts crunchy underfoot in the mornings.  The very cold temperatures gradually eased with the return of the early mists and some light rain.  This gentle warming meant that by around the 10th of the month the almond trees had started coming into blossom – a sure sign that we should be finishing the pruning.  But the earliest flowers to bloom were faced with a tough challenge almost immediately as a depression in the Bay of Biscay sent a violent cold front across the Iberian Peninsula, heading in a south-easterly direction.  This air mass was extremely unstable, and brought some truly terrible weather from the 16th onwards.  There was plenty of thunder, and an almost incessant flashing of the light, partly due to lightning and partly due to the electricity flickering on and off repeatedly.  There was also torrential rain, and when that let up, hail. 

These conditions put everything on hold again in most vineyards, with several working days missed, except for one or two hardy quintas where they bravely struggled on with the last of the pruning.  There was snow on the Marão again, predictably, and on the coast very high winds were whipping the waves up into double figure crests (metres, that is, not feet).  A couple of people were reported swept away as the swell crashed over sea walls, and many trees were brought down – including one in Porto that unfortunately fell on top of an occupied car.  Closer to Lisbon, a tornado was reported in Pamela (this seems to be becoming something of a habit of late).

The awful weather caused some problems in the new plantations, especially those that involved old stone walls.  Cutting narrow (mechanised) terraces between the walls, (and then turning over the soil to enable planting) obviously disrupts the naturally-formed and decades-old micro drainage channels in the soil.  Heavy rain therefore encourages a weight of water to build up behind the walls that would previously have infiltrated away more easily, and there were some localised collapses.  Likewise, even on the more conventional earth-banked patamares, there was some minor slippage in places.

When the storms eventually passed we finally got some good weather.  It turned beautifully sunny and warmed up in really quite a pleasant fashion for the last week of the month.  After what had been a pretty nasty winter, it suddenly felt spring-like with temperatures eventually climbing into the 20ºs again.  Details from our weather stations showed, in spite of the bright finish, that the balance of the month in Pinhão (at 8.8º C) was towards the cold side, coming in almost one degree below the average for February (9.7º).  On the other hand, the cold days were not especially cold and there were only a couple of frosts right at the start of the month.  Top temperatures were generally tolerable, but this was the third month to register below average temperatures out of the four that have made up the agricultural year so far, so it is fair to conclude at this stage that it has been a cold winter.

It has also been a reasonably wet winter, even though February itself was not especially heavy in terms of precipitation.  Pinhão experienced only around two-thirds of the reference value.  The rainfall graph shows that the two drier than normal months so far this year have left us with a cumulative total of around 130 mm.  This is a little below the average for this stage, which is about 160 mm.  The small shortfall is of course of no consequence, especially considering the amount of rain we had before Christmas.

Life in the vineyards in February is not normally particularly inspiring.  Some quintas still had the last of the pruning to finish off, whilst others got on with more trellis repairs.  The trellises weren’t the only parts of the vineyards that needed repairing – many of the tracks had been damaged by run-off from the storms and, as was mentioned earlier, some of the earth banks on the terraces had slipped.  There were also localised stone wall collapses and all these points needed attention.

With still some way to go before budburst, the labourers at one or two of the quintas where the winter work had progressed more promptly found themselves at something of a loose end.  A useful remedy for idle hands could be found trimming back the various almond trees scattered around the properties.  As with olive trees, the pruning cuts on almond trees need to be fairly drastic to encourage the best shape of the tree in the long term, once new growth springs back.  After all, aesthetics plays a part in amygdaliculture too.  Almond trees are dormant during the winter which meant that this is the best time to prune them – i.e.  before the blossom comes out.  Unlike most plants, almond trees flower first on their bare branches, and only after fruit set do the leaves start to grow.  Incidentally, it is a little-known fact that the almonds at Quinta da Vila Velha are certified organic.

Attention was next turned to planting what are known as ‘americanos’.  These rootstock (non-vinifera) vines are not usually used in the first year of a new vineyard where we would prefer to plant ready-grafted rootlings, but really they are the only practical way to fill in falhas (gaps where a vine has died) in established vineyards.  This is because they are much hardier and their drought-resistance means that (even with the roots trimmed) they just need to be stuck in the ground and forgotten about – no watering required.  In a year, or maybe two, they should be thick enough for grafting on a scion of the required vinifera variety.

By this stage of the year the majority of the surribas had been completed and the machinery finally left us.  Soil analyses are then taken and, based on the results, corrections will need to be carried out.  These habitually take the form of calcário (lime) to reduce the acidity of the soil, organic matter, and a compound NPK fertiliser to get the rootlings off to a good start.  Once this lot has been ploughed in we can get on with the business of actually planting the new vineyards.

One factor that should be considered at this stage is whether the vines are eventually to be trained onto a bilateral cordon or a unilateral cordon.  In recent years, for various reasons, there has been a tendency to set up most of the new vineyards for unilateral training.  The main advantage of this is that the vines can be planted a little closer together (80 or 90 cm, rather than the standard one metre) so the density of vines per hectare is greater.  Although planting density is a factor in the attribution of benefício, more important is the fact that there are legally-enshrined minimum densities for both vertical plantings and terraces.  Furthermore, payment of the subsidies available for reconverting old vineyards also demands that certain limits are respected.  Lastly, of course, training the vines is a little quicker and easier if a unilateral cordon is chosen.

In addition to deciding what sort of cordon is to be used, in the case of unilateral it actually helps to consider in which direction each row to be trained.  The reason for this is that the last vine in the row at one end can actually be planted outside the end post (but inside the strainer) and still be trained inwards onto the cordon wire.  At the other end of the row it cannot, since being trained in the same direction would take it away from the fruiting wire and leave us with nowhere to secure the tip.  On a flat vineyard it is recommended that machinery such as the pre-pruner works with the grain, so to speak, always travelling in the same direction as the bend in the vine’s trunk.  This will theoretically minimise damage to the vines.  Since our tracked tractors can turn on the spot the direction of the curve will alternate between rows.  This means that we need to plant the last vines in every other row one space further out at one end, and correspondingly one space further in at the other end of the row.

On terraces the same theory means that the outer row is always trained left to right as you look at them, and the inner row is trained from right to left.  It has to be this way around as the pre-pruners and shoot trimmers are mounted on the right hand side of the tractor.  Vertical plantings are an exception, however, as the cordon should inevitably be trained downhill.  This should give a more balanced plant, as the vine’s negative geotropism is played off against the shoot tip’s apical dominance.  Training the cordon in an uphill direction compounds the two effects and leads to an excess of vigour in the buds at its end.