The soil that cultivates water. In conversation with Lorenzo Costa
Like his Renaissance namesake, a great artist at the court of the Este family, Lorenzo Costa paints new morphologies by shaping the soil with water. An Italian pioneer of permaculture, his practice responds to three imperatives – to slow down, to distribute, to infiltrate – by listening to and respecting the land of Chianti and cultivating, like his fellow countryman Leonardo, the spark of experimentation.
Federico Tosi
«I started studying water behaviour in 2015 and have been working on it since 2018. Since then, in my 2.5 hectares of land I have infiltrated 6 million 200 thousand litres of rainwater, and today I can count on 19 infiltration basins, with a total capacity of 190 thousand litres and a 250-metre long network of channels».
Tuscany. Four hundred metres above sea level north of Siena, town of Gaiole in Chianti. Before setting up orchards, vegetable plots and arable crops, Lorenzo Costa here decided to cultivate water, a rare commodity in this era, difficult to retain in the steep hills of this stretch of the Apennines. A terraced agricultural area, with five kilometres of dry-stone walls, work of a man who centuries ago changed the hilly orography by integrating himself into it, without forcing. It is easy to explain why Lorenzo Costa did not want to redesign the land according to his agricultural needs, perhaps with the great gimmick of a reservoir and a network of pipes and pumps, seeking instead to capitalise the rainwater destined for this slice of land: because in this way the soil is more efficient, richer and splendid to admire in all its different expressions.
«Today, the management of rivers and streams is no longer there. It is not a question of cleaning the banks, we do not respect the riparian strips. Every river has a riparian strip that acts as an expansion basin in case of flood. But right because we have dammed rivers, it is obvious that this one overflows and floods. And if those extra metres are taken away, what’s it supposed to do? The run-off time indicates how long it takes for a drop of water to reach the outlet of the reservoir, starting from its furthest point. By increasing forest felling and reducing the riparian strip, we are also reducing the time it takes for the drop of water to reach the sea. And it’s billions of drops… The more their speed increases, the more erosion, runoff and soil damage occur».
«When we go to work ploughing soils with slopes of more than 20%, it is obvious that they are prone to erosion. When we want to increase the cultivated area by ploughing, it is obvious that we increase erosion. A while ago, fields were smaller. They were cultivated differently. Fields were full of tree s trips, hedges, rows of orchards mixed with arable land. To increase the sowing area, we removed all the trees, which now no longer can perform the function of rainwater management. If we remove the trees at the edge of the fields, we reduce the soil’s capacity to retain water».
«How I learned: by necessity. Mine is a soil subject to erosion, to compaction, and out of necessity I had to learn how to manage water. Over time I have learnt to change my point of view, reasoning from the perspective of water. Often, in agriculture, we reason on soil, yield per square metre, micronutrients… All of this is right, but at the root there is always water. Water supports growth processes, plant nutrition and microbial activity. Without thinking about water, everything we focus on wouldn’t work».
«Actually, for me, it has also been about using as little water as possible. This led me to change production: in order to use less water, there are plants that I don’t grow. Lettuce: I plant it in spring, f inishing it in June and replanting it in September. Lettuce is water, and in order to produce it, with the temperatures we have today, we would have to use insane amounts of water. I prefer to do it this way, explaining why and finding substitutes such as Asian mustards, Mizuna, Mibuna, spicy varieties… This year we have started working on a farm project to create a mix of succulents (Sedum acre, Sedum rupestre and others we are selecting). They are heat-resistant, drought-resistant plants. Chefs must also be taught to change. It is a great work of cultural re-appropriation, that we have to carry on as farmers».
«Rarely, in agricultural treatises, there is a chapter dedicated to water. It is taken for granted».
«Water favours all those processes of growth, plant nutrition and microbial activity that agriculture focuses on».
«Over time I have learnt to change my point of view, reasoning from the perspective of water».
Tone of voice, choice of words, linearity of concepts, emphasis… In a dialogue between people there
are several elements that allow us to assess the competence and reliability of our interlocutor. With
Lorenzo Costa we go further: not only he does transmit his knowledge to you, he gets you into it. With
his words he seasons with science and logic the assumptions he started from, and with passion he
guides you on the techniques he has identified, on the inventiveness supporting curious people from
an early age. He is generous with his sharing because he knows that his example is a replicable, result
oriented and harmonious approach to the human/nature relationship.
A graduate in Contemporary History, Lorenzo Costa is 47 years old, a research technician at the
University of Siena, a farmer, and certainly a populariser.
Like soil, like water. «Steep and prone to erosion. Studying my soil, I started to develop a series of techniques to reduce the effect of water». In the actions implemented to reduce erosion and runoff, «it became obvious that I could use that water. In order to reduce its flow velocity, I retained it in the soil, thus utilising it in different ways. What does all this mean? Putting it in the ground. The best place to store water».
«It was natural for me, in the end, to come to the fact of fixing and summarising it all in three words: Slow Down, Distribute and Infiltrate». Each soil must have its own water management. This emerges when Lorenzo explains the three actions – Slowing down, Distributing and Infiltrating – chosen to design water management, three approaches that do not say how to do it, but only how to understand soil in relation to water.
Slowing down the speed and the flow rate of water, in order to reduce soil erosion.
Distributing water by studying the orography of the terrain.
Infiltrating the water into the soil, the best place to retain it because this is where it evaporates the least, stimulating microbes and plant life.
«When I started to reason on water, it was necessary to take into account its cycle but also, perhaps above all, the concept of hydrographic basin. When it rains, water collects in a hydric body – a river, for example – and all the rain that flows into it draws what is called a hydrographic basin. If I reduce this concept to a company, to a mini-territory, we talk about catchment area». «This led me to think about water starting from where the drop of water comes down, following it from the exact point where it touches the ground. Only then can you understand how it behaves. If I look at a terrain observing the water at the point where it collects, I am already done. If, on the other hand, I look at the water from where it starts its runoff, I find all the points where it is efficient and effective to manage it. The water over my land is that one, no more, no less. If I follow it and distribute it in its movement along my soil, I manage the same amount of litres, but less at a time. This goes into hydrating the soil much more effectively, because I collect and manage it in more places. And it is nontrivial. We often get to think of a reservoir but then, in order to use it, I need to pump it. It has no sense of efficiency. Water, by its very nature, flows downstream; if we get to think effectively and efficiently, I will be able to manage water from the highest point of catchment, taking advantage of gravity».
«Channels, infiltration basins eighty centimetres deep, one metre deep at the utmost. We do succeed in collecting water in the quantity that descends on the available land, with specific solutions depending on the area. I started studying water behaviour in 2015 and have been working on it since 2018. Since then, in my 2.5 hectares of land I have infiltrated 6 million 200 thousand litres of rainwater, and today I can count on 19 infiltration basins, with a total capacity of 190 thousand litres and a 250-metre long network of channels. Water that has not flowed out of my land but, on my very land, has been infiltrated».