Giovanni Pascarella is 52 years old and manages Extendavitis, a team of about ten people who sign consultancies with consortia and companies between Veneto and Friuli Venezia Giulia for years. He is originally from Valdobbiadene and therefore, almost by fate, he specialized in viticulture. His role is to touch the earth, to know it and understand it to explain it to those who cultivate it how to behave with her. She is obviously the center of attention the role of waterfundamental for agriculture, from vineyards to corn.
Let’s start with the water bomb of these hours. How is it possible to define the damage it actually causes to crops?
«Formulating estimates in these cases is always difficult because there are numerous factors to consider. The first is certainly the hydrogeological one: if there are landslides then the risk is that the damage will be total. But it happens in limited places, so the real problems are linked to the amount of water that falls.”
Is it possible to define a risk based on the volume of rainfall?
«The theme is not the single 100 millimeter event in an hour. That water slides off, perhaps causing no apparent damage. But even if you see a dry field on the surface, the earth down there is soaked. We estimate that it will take at least ten to fifteen days to bring the soil back to its optimal state. But sometimes it even takes a month, depending on whether the substrate is gravelly or clayey.”
As long as it’s not raining yet.
“Indeed. Since the beginning of the year, 900 millimeters of rain have fallen in the Valdobbiadene area, 1,400 millimeters have fallen in a year and we expect a rainy May. Wet soil will cause downy mildew to spread, which we will need to treat. The fungi also spread on fruit trees or among arable land. The damage is caused by the plant diseases that damp soil generates. Some examples: the peach tree is affected by the blister, the apple tree by scab.”
While the soil dries out, what can farmers do?
«Nothing, and this is a paradox. We are able to cultivate dry soil, not wet soil. Think of a tractor entering a wet field: with the pressure of the wheels it causes compaction of the soil, which thus loses oxygen and empty spaces. The roots will have less space to grow and strengthen.”
Could something be improved on the works front?
«Water regulation is necessary. It would be good if there were more micro-ditches and drainage channels around all the fields, which must be dug to lead to the ditch heads and then gradually to the rivers. These systems prevent water from ending up on the roads.”
Then there are the rolling basins. What role do they have?
«They are excellent for avoiding floods. They can also be used for crops, although the risk is that the crop will have to be thrown away if a river needs to be diverted into it to slow down its flow.”
After the rain, the sun. How to manage summer drought?
«The reclamation consortia bring us pressurized water. When it’s missing it would be nice to have huge pools to draw from. I often mention the Vajont: it was a huge tragedy, but if we had basins of that size we could solve many of the problems during the summer months.”
Could we also think of small lakes in the plains?
«It’s complicated: the land is often man-made, it wouldn’t be easy to find the spaces. But I am also thinking of quarries, which could be used in this sense. Much easier on hills or mountains, in natural depressions. An interesting mediation on the Prosecco hills is that of the small basins shared between winemakers, who fill them these days and then use them in the summer. The issue of fresh water conservation will be increasingly important as the years go by and the enormous challenge is to design water networks that help us in periods of drought and save us in times of floods.”
