April 2008 Douro Insider

April got off to a very fine start – indeed, April 1st was the first day of the year which could reasonably be described as hot.  Seriously, it was.  What with the changing of the clocks a few days before, the golden evening light hung on until much later, joined by warm, soft breezes that insistently whispered the words ‘gin and tonic’ until their demands were satisfied.  The impression that summer was creeping upon us was further enhanced by the onset of the hay fever season, another of the annual rites of passage.  The evenings were hot too and plenty of people were seen wandering around in shorts and T-shirts at night as if on holiday.  All this occurred, oddly enough, when much of the UK was still plagued by snowfalls.  The early summer was somewhat short-lived, however, and the second week of the month changed dramatically for the worse with some torrential and long-lasting rain.  This then set off a four week long cycle of completely polarised weather fluctuations.  With great precision, hot and sunny weeks were interspersed with cold and wet weeks for the rest of the month.

In the vineyards there was fortunately only very minor damage to the tender young shoots from the wind-whipped rain, and it was nothing compared with the tornado that hit Santarém (a city about 75 km northeast of Lisbon) on May 9th.  This vicious storm brought winds in excess of 200 km / h that destroyed buildings and uprooted trees.  Access to Lisbon along the Tagus estuary road was cut off by waves which breached the sea wall on the same day and, back in the Douro, the weather seemed to be changing twice an hour, flitting between flashes of sweaty, thundery sunshine and sudden intense showers that turned the farm tracks into treacherous mudslides.  On the new terraces that were cut for this year’s plantations there was a small amount of damage to the earth banks and, though none collapsed completely, the slippage of earth was sufficient to (temporarily) bury some of the newly-planted rootlings until they were dug out again.  The first year is always risky for terracing as the freshly-bulldozed soil is less compacted and therefore less stable.

A period of all-day, non-stop downpours delayed the first phytosanitary treatment of the year, the application of powdered sulphur, because it doesn’t work when conditions are cold and wet.  Nor, indeed, do the vineyard workers particularly enjoy themselves.  The combination of plenty of rain and minimum temperatures that kept above 10º C also sparked the vague possibility of primary infections of downy mildew.  Had this occurred it would have been a very early attack, especially since the shoots were so little developed at this stage and the canopy therefore very well-aerated.  Without wishing to get anybody excited, it does appear that there are plenty of flowers already visible, certainly more than usual.

Then came five days grace with beautiful weather returning, in spite of the pessimistic forecasts.  Dramatic displays of wild flowers burst forth, stimulated by the preceding rains, and the Spanish lavender was particularly attractive both in its intense purple colour and decadent aroma.  As the sun came out again the air was shrill with the iridescent chirping of the Bee-eaters, newly returned from wherever they find bees to eat during the winter.  It may be that their prevalence was encouraged by the cover crops coming into bloom.  With the clover in flower the vineyards were audibly buzzing with a multitude of insects and birds.

Things turned nasty again on the night of the 16th as the second spell of bad weather got underway.  There was plenty of rain and high winds, resulting in the odd torn leaf in the vineyards, but nothing serious.  Thus followed another terrible week, but we still needed the water so nobody complained.  Then, after two wet spells we had our second dry spell, coming just in time for the public holidays at the end of the month.  There was masses of sun and some very hot temperatures in parts, often climbing well over 30º.  It really felt like summer again and was clearly time to fish the swimming trunks out of the drawer.  The blossom came out on the orange trees and the scent in the air was fantastic.

But what did these bizarre weather patterns mean on balance, compared with the long-term means? As the graphs below show, we had much more rain than the average for April (see the bars, plotted on the left-hand axis) and now finally the cumulative total for the year so far (the lines, on the right-hand scale) has caught up to where we would like to be.  In fact, only three of the last 12 months have brought above-average precipitation so April’s total, at 144 mm, was very welcome indeed, almost three times the mean value (53 mm).

In terms of temperatures, for all the wild fluctuations the average came out very close indeed to the mean, with the 14.6º registered in Pinhão just 0.3º higher than the expected value.  The absolute range, running from a chilly 5.6º all the way up to a summery 30.9º shows quite how varied the month was.  Most days dropped below 10º at night but almost a third (nine out of 30) also got above 25º.

At this time of year, early on in the growing season, there are two important activities whose undertaking is essential to ensure that the vines get off to a good start.  These are often carried out more or less simultaneously, depending on the growth of the vines and, more probably, the state of the weather.  They are, of course, the first application of sulphur and the despampa.  Whilst the latter can be carried out (with varying degrees of contentment) in virtually any weather, the sulphur is washed off by the rain, an has little effect at low temperatures.  Thus often the climate dictates the order of what goes on in the vineyards in April.  The dusting of the vines with pure sulphur is carried out to protect the tender young shoots against powdery mildew.  The benefits of this organically-approved, naturally-occurring fungicide have been known and used since Roman times.  This year the first application was not completed everywhere on account of all the rain.  Not only did this complicate the treatment, but it also created conditions somewhat propitious for infections of downy mildew.  Thus, in many instances, the first treatment of the year was a combination spray of two different fungicides – one against powdery and the other against downy.

The other activity, despampa, consists of manually removing what are technically know as ‘non-count shoots’ – in other words any shoot that is not borne of a fruitful bud deliberately left behind at pruning time.  This process has a number of beneficial effects: it thins out the canopy leaving it more aerated and therefore less at risk of fungal diseases and it also reduces the chances of bunch shading by non-productive shoots in the future.  In addition, it removes a potential nutrient sink at the growing tip and prevents the development of a shoot that would otherwise consume water (a resource certain to be in short supply later on in the season) without offering much in return.  Occasionally one or other of these shoots, if it is favourably positioned, is kept for the specific purpose of creating a new, lower spur at the end of the year, to bring down the pruning level closer to the cordon again.  The timing of this shoot thinning is important – when carried out at just the right moment the unwanted shoots are very fragile and can be easily snapped off at the base with the fingers.

So whilst the first treatment (whatever products it consisted of) and the shoot thinning were by far the major activities, there were a number of jobs from the early spring yet to be finished off.  Weed control was turning out to be something of a problem this year, with plenty of water and some pleasantly warm spells encouraging growth.  Ploughing was therefore required as a control method at many of the quintas in the Douro.  But in spite of all the natural vegetation abounding, we also experienced a small degree of rabbit attack in one of this year’s new plantations.  Just as the rootlings burst forth with the very first leaves they have ever produced, unscrupulous rodents were taking advantage of these tender young shoots for an early morning snack.  The vines are understandably very fragile at such an early stage and serious damage could kill them, so we protected them with grow-tubes until they grow tall enough to keep their leaves up out of harm’s way.  There was only one other activity going on this month, featured at many of the properties, but it was not strictly viticulture.  Pruning and trimming the olive trees to ensure regular production and ease of harvest was also considered to be a necessary undertaking.

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