November 2011 Douro Insider

Torrential rain fall - and sunshine - in the Douro in November

After yet another dry month in October (and apparently also the warmest October since 1931 at a national level), it was pleasing to see that the roads in the Douro were running like rivers on the 2nd of November.  The rain was torrential, and accompanied by high winds, but one felt nevertheless that the soil had been baked so dry and compacted over the long summer that this run-off was simply due to a lack of infiltration rather than the sheer volume of water itself.  One of the greatest problems with mountain viticulture is that so much precipitation is lost to the slopes rather than seeping into the soil.  In any case, what fell was welcome, and we enjoyed a very wet first week of the new agricultural year.

Conditions then turned less interesting: temperatures dropped and the mood was basically foggy, with some low level drizzle.  Around the middle of the month the rain returned dramatically (although the fog didn’t let up much initially) as an incoming warm (and very damp) front brought a decent downpour for S. Martinho.  There was a certain amount of turbulence too, with some high winds blowing plenty of leaves off the vines.  This was really the only wet part of the month, outside the first couple of days, although it was definitely the case that the south of the country got the better of the rain, with some flooding occurring in the Lisbon area over the weekend of the 18th and 19th.  After that it perked up again for a week or so, with clear skies and some moderately warm temperatures even hitting 20º C.

Going into the last week of November conditions were influenced by an anticyclone which appeared over the north-western corner of the Iberian Peninsula and kept the clouds away, ensuring a fine end to the month.  It was, however, easily the coldest time, with a very small amplitude between the daily minimum and maximum temperatures, the latter of which, for the last few days, didn’t even make it up as far as 10º C.

Although November in itself produced an average temperature identical to the long term mean in Pinhão (11.6º), there was news from the Instituto de Meteorologia, who pronounced this autumn (consisting of the months September, October and November) the third warmest since 1931.  For those who remember the balmy vintage weather this is not altogether surprising.

Meanwhile total monthly precipitation, which came in at 104 mm, was just a little over the average (87 mm).  This makes November only the second month since the start of 2011 with higher than average rainfall – and the first one was August which delivered only a single millimetre above the mean.

What this means is that the usual rainfall graph below looks rather worrying at the moment.  We have had a cumulative total of just 406 mm of rain so far in 2011 when the average at this stage is 589 mm.  Worse still, the vines have their roots so far down that they respond to soil moisture at a depth which depends on more than just a single year’s precipitation.  The reality is that a few feet below the surface the earth is really quite dry, so even a wet winter might not be enough to replenish the long-scale reserves.  We must hope for plenty of rainfall in December and January.

If such a thing exists in viticultural terms, then November is something of a utility month.  With the vines starting to go into dormancy but not yet in any urgent need of being pruned, those with time on their hands can use the month to address pretty much anything that they would not normally consider particularly time-sensitive.  Fertilisation is a good example: given that the two macro-nutrients generally most lacking the Douro are potassium and phosphorus, both of which have low soil mobility, it takes months or even years (depending on the amount of rainfall) for them to become available to the vines.  Thus that which is not taken up next spring will still be there during the summer, and more again will still be available the year after.  Ideally, of course, this type of fertiliser should be applied before the winter rains so November is an excellent time.  This is quite unlike the situation with nitrate-based fertilisations, however, as they are easily leached away in the soil water and so should only be applied when the vines are actively consuming nutrients.

Whatever else we might wish to achieve in November, it is unadvisable to forget about the pruning altogether.  There are two public holidays at the beginning of December without even starting to think of the days lost over the festive season.  Any self-respecting quinta would hope to have the pruning at least 50% finished by the end of the year, so to some degree this dictates how much time is available for other operations this month.  Pre-pruning, pruning and cane shredding therefore appeared on all the time sheets to a greater or lesser degree.

The olive harvest in the Douro is entirely manual and time consuming on our steep terraces

A brief summary of the debate over the economics of olive production in the Douro was given last month.  To recap, the logistical difficulties created by poor accessibility and manual picking, often on walled terraces, make olive production in the Douro unsustainable for many farmers, with the possible exception of organic producers whose product is sold at a premium.  Those who did decide to pick, however, started soon on in the month as the olives were clearly ripening early this year.  Although yields were reasonable, there was unfortunately some insect damage to the fruit which allows oxidation and tends to push up the acidity of the olive oil, much in the same way that traça (European grapevine moth) can be responsible for volatile acidity in musts and wine.  Nevertheless, much of the production came in comfortably within the range classified as extra-virgin.  Whilst Douro olive oil is not cheap to produce, the quality is usually excellent.

Between pruning, fertilisations, sowing cover crops and picking olives there was plenty to do in November.  But at many properties across the Douro one other major operation got underway – we got started on the new plantations of 2012.  Most people don’t realise that the vineyards that have been earmarked for replanting were already being treated in a different way more than a year ago.  Pruning, for instance, would have been cursory at best last autumn; since there is no need for sustainability of the vineyard we would have basically done little more than a quick hedging, leaving much longer spurs than usual.  This should at least have ensured that the last crop was a big one, without worrying about overstretching the vines’ reserves.  After the harvest there is no need to wait for the vines to reabsorb nutrients before leaf-fall: the trellis can be taken down immediately, the wires recycled and the vines pulled up whilst still green.

Scarifier used to break up and turn over vineyard soil

Whether planting on virgin terrain, or replanting a dilapidated old vineyard, soil preparation is crucial.  This procedure is contracted out to specialist companies which provide bulldozers and diggers to smooth out the surface of the ground, cut terraces and turn over the soil down to a depth of about one and a half metres.  They also remove the largest outcrops of rock to ensure that the new rootlings can quickly establish deep root systems with relative ease.  One of the biggest problems which often blights the surribas (terrain preparation) is that the machinery is incapable of producing a satisfactory result if the earth is too muddy.  Thus waterlogged soils inevitably mean that work must be suspended, which can have potentially serious knock-on effects (delays in the surriba could mean that we are forced to plant too late in the spring, for example).  Fortunately this autumn there has been no down-time so far.

5 thoughts on “November 2011 Douro Insider”

  1. Thanks, Roy! Miles is a brilliant writer when we can get him away from his vines, it’s great to hear his voice in the Blog and Douro Insider.

  2. A good information about the weather at Douro, and the effects in the wine(future).

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