March 2009 Douro Insider

March was a remarkable month for weather in so much as virtually nothing happened. After a shaky start quickly passed, it was the same thing day after day after day – almost like living in the tropics. The sky was blue, there were no clouds, no rain, no wind and hardly any change in temperature for the majority of the month. The only significant digression from this pattern came right at the very beginning, and it was the fault of the Americans.

March got underway for the East Coast of the US much as February had done for the UK, with massive snowfalls bringing serious disruption. These ‘snow emergencies’, as they were called, were mercifully short-lived but the storm that had caused them then set off out into the Atlantic, and minor repercussions were felt along the edge of Europe. As far as the Douro was concerned this materialised in the form of gusty north-westerly winds which removed the last of the almond blossom from the trees after a very pleasant first couple of days of the month. Things were momentarily unsettled with only a few brief glimpses of the sun caught between the dark clouds blowing quickly across the sky, and there were plenty of showers. Herbicide applications had to be suspended for several days on account of the breeze.

Then came fantastic spring weather which lasted until the end of the month, and then some. It felt especially warm after all the snow the winter had brought. We enjoyed day after sunny day of impeccable blue skies and lengthening evenings to the soundtrack of birds singing and insects buzzing through the blooming flowers. Temperatures reached into the high 20ºs here in Pinhão and even in Britain meteorologists agreed that it was the sunniest March for 80 years. It eventually chilled quite a bit towards the end of the month but still remained sunny.

But what was the overall effect on the grapevines of a very cold winter followed by a very warm start of spring? Perhaps predictably, they appeared to practically cancel each other out. Whilst normally cold winter weather will delay budburst (as a natural protection against frost damage) the closer one gets to the start of the cycle the more weight the current climatic conditions have, meaning that on balance the hot March probably woke the vines sooner than one might have expected. The ‘official’ date of budburst from our experimental vineyard was the 17th March in 2009, curiously exactly the same day as last year. This date is an average value for the four most widely grown grape varieties, and in this case planted on a number of popular rootstocks. It could be considered in general a little earlier than usual for that area which normally sees budburst around the 20-somethingth of March.

The specifics recorded by the Pinhão weather station do indeed confirm that it was an abnormally warm month. The average temperature of 13.6º C was far higher than the long-term mean (12.3º) and the hottest corresponding figure for six years. In all we had 11 days over 25º, and a peak of 27.1º. It did drop as low as 3.5º on one occasion, but for the majority of the month the daily minimum was reasonably stable between 5º and 10º.

There were only two wet days in March, consecutively and during the first week, but one of these brought no more than a spot of drizzle. This left us with a monthly total precipitation of just 6 mm (clearly a very long way short of the long-term mean, which stands at 52 mm) and means that we registered the driest March since 2000. Low March rainfall is by no means uncommon, however, and a quick check of the records reveals a curiously high number of very dry Marches with plenty of single figure monthly totals.

With this year’s cumulative total precipitation practically stagnating, as the figure below clearly shows, we have moved from the position of a slight relative excess to a slight shortfall. In reality the situation is worse than it seems, however, coming on the back of two dry years. It would be true to say that the discrepancy between where we are now and where we would like to be is growing worryingly – we really need to be quite a bit ahead of the mean to compensate for the past. Thus April will be a very important month for the soil to recharge its water levels otherwise the vines might well be at risk of suffering severe water stress in the summer. May’s rainfall can be considerable in terms of quantity but since it often comes in downpours much is lost as run-off. Even a small amount of rainfall now will be a benefit, if only to temporarily stave off the first irrigation of the new plantations and the expense this implies. Cooler weather will also keep the rootlings green for longer.

The imminent onset of budburst around the middle of March conditions the timing of the major vineyard undertakings this month, and usually means that we are extremely busy. Matters are further complicated by the fact that there are a considerable number of relatively ‘minor’ operations to be carried out in a short amount of time, implying that the work, although varied, tends to be very fragmented. Often it requires splitting the pessoal (workforce) into different teams, working in different parts of the quinta, and this can certainly complicate life from a logistical point of view. As usual there are a number of non-discretionary services which are essential at every property without exception, and there is also the usual assortment of less prevalent jobs – either one-offs specific to certain quintas, or other more common tasks that are taking place outside the usual timeframe for some reason.

The more universal procedures are focused (or perhaps dispersed) around three main poles: trellises, weeds and falhas (missing vines). Firstly, trellis repairs were still ongoing at the start of the month for most quintas, although beginning to wind down. The posts and wires must be in place soon as rapid early-season shoot growth will need to be contained. In certain parcels some old trellises have completely replaced by new ones, thus allowing the vines to be retrained to a higher and more modern system, and thereby giving them a new lease of life. Wooden stakes are now used instead of the traditional old blue schist slabs as they are lighter, less fragile and altogether more practical.

In second place, we must consider the weed situation. Unwanted vegetation is controlled both by ploughing and by the application of chemical herbicides, as we saw in quite some detail last month. Accordingly no further elaboration is considered necessary here. Suffice to say that the related practice of manual talude maintenance featured too at a couple of quintas.

The third point, the replacement of falhas to fill in gaps in the vineyards, involves two quite distinct phases. The first is the planting of the American rootstock, and the second, a year (or two) later, is the grafting onto it of the desired vinifera species. March is a busy month for both parts of this process which are usually carried out after the herbicide applications. There is another alternative, often used in the second year of a new plantation where the close spatial distribution of the plants makes watering feasible, and that is to use bench-grafted rootlings again. Whilst on the subject, we must not forget that the 2009 plantations were nearing termination in general and this entails all sorts of associated processes apart from actually sticking the plant into the ground. It may be stone clearing, or opening up caldeiras (depressions around the base of the vines) to catch irrigations and rainwater; these will continue to be beneficial over many years. At another of our properties the reconversion of some extremely old terraces meant that many days were spent rebuilding damaged or collapsed walls, whilst grow-tubes were also being applied to several first and second-year vineyards.

The other secondary operations of the month are, as we have mentioned, extremely diverse. A few of the quintas were still finishing up the pruning as the month got underway and others, though the secateurs had been cleaned and put away, hadn’t yet got round to dealing with the cut canes. Or indeed, in other cases, the uncut canes. Erguida (cane tying) therefore still featured at one or two vineyards in March, and we even had some late fertilisations being carried out sporadically.

Finally, we move on to the post-budburst jobs. The first of these is usually despampa (shoot thinning and desuckering) which is carried out as early as possible for two reasons. The shorter the shoot is the more easily it snaps off at the base, and of course the less we are wasting the vine’s reserves on unnecessary and unwanted growth. At one or two of the quintas with earliest budburst, this was being undertaken before the end of the month, whereas others had already moved on to sulphur application, about which we will hear much more in April. And finally, as if all this was not enough, it was olive tree pruning season at a considerable number of properties, a laborious procedure which often needs to be contracted out to external teams. In short, it has been a complicated month which we are not sad to see the back of, in spite of the delightful weather which made it possible to get an awful lot done.

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