Thirsty: Strawberries

Drive south from Seville toward the Atlantic in January and the land turns white. Not snow: plastic. The plain between the pine forests and the sea, around the towns of Moguer, Lucena del Puerto and Almonte in the province of Huelva, is covered for tens of kilometres in low tunnels of translucent polythene, each one a few metres wide and hundreds long, and under them, on raised beds wrapped in black film, are strawberry plants in fruit in the middle of winter. Pickers move through the tunnels bent double, filling punnets that will be in Paris or Berlin or London inside three days. Huelva grows most of Spain's strawberries and Spain grows most of Europe's winter berries, and the plain is the reason northern supermarkets have strawberries in February.

A punnet of strawberries carries about 140 litres of water. This article is about where that water comes from, why a small number can carry a large consequence, and what the strawberries of Huelva have done to the wetland next door.

A shallow plant

The strawberry is a low plant with roots that reach a few tens of centimetres into the soil and a fruit that is about ninety percent water, picked over a season of months, and it is grown, in the commercial trade, almost nowhere on rain alone. The plant wants water every day in small amounts, the fruit splits and rots if the soil swings between wet and dry, and the seasons in which it is most valuable, the winter in Spain and the long summer in California, are the dry ones. So it is irrigated, by drip tape laid under the plastic mulch of each bed, from a well or a canal, a little at a time, and the blue share of its footprint is one of the highest among fruits: about a third of the total, against a tenth for a banana.

The number per kilogram is small, among the smallest on this site, because the plant is small and fast and the fruit is heavy with water that is counted in the yield. The reason the strawberry belongs on this site anyway is the blue water and where it is drawn.

Huelva

The plain of Huelva was pine forest, sand and marsh until the 1980s, when the Spanish and then the European farm policies and a motorway to the north turned it into the strawberry garden of Europe. The soil is sand, which drains and warms fast, the winter is mild, the sun is more than the north gets in summer, and under plastic the plants fruit from December to May, when nowhere else in Europe can. The area under berries grew to about six thousand hectares, and the water for them came from the only place it could: the ground. Under the sand is an aquifer, recharged by the winter rains, that extends south and east under the pines to the marshes of Doñana, and the wells that water the tunnels draw on the same body of water that keeps the marshes wet.

Doñana is the largest wetland in western Europe, a national park of marsh, dune and lagoon at the mouth of the Guadalquivir where half the birds of Europe stop on their way to Africa, and its lagoons, the ones that hold water through the summer, are fed from below by the aquifer. As the wells multiplied, and a share of them, estimated by the conservation groups at about a thousand, were drilled without a permit on land cleared without one, the water table under the park's edge fell, and the lagoons began to dry earlier each summer. The Santa Olalla lagoon, the largest permanent one in the park, which had not dried in living memory, was dry in the summer of 2022 and again in 2023, and the scientists who monitor it attribute the loss to the wells as much as to the drought.

The court and the law

The European Commission took Spain to the Court of Justice over Doñana, and in June 2021 the court found that Spain had failed to take account of the illegal abstraction in its water planning and had failed to protect the habitats that depended on the aquifer. The ruling obliged the governments to act; the regional government of Andalusia instead proposed, in 2023, a law that would have legalised irrigation on several hundred hectares of land farmed without permits, on the argument that the farmers were families who had been there for decades. The conservation groups, the scientists, the national government and the Commission all opposed it, the supermarkets that buy the berries said they would not buy from illegal land, and in late 2023 the regional government withdrew the law in exchange for a national package of about 1.4 billion euros for the area, to buy out farmland, restore the marsh and pay farmers to move to crops that need less water. The wells that were illegal remain illegal, and the enforcement, which is the closing of wells and the pulling up of plastic, has been slow, because the farms are the plain's employer.

The plants and the plastic

The strawberries under the Huelva tunnels are planted every autumn and pulled up every summer. The plants come as bare rooted runners from nurseries in the cold high plateau of Castile, where a summer at altitude and a first frost set them to flower, and they are planted in October into beds of sand that have been raised, shaped, laid with drip tape and wrapped in black plastic, a hundred thousand plants to the hectare, under tunnels that go up the same week. The plastic does three jobs: the mulch stops the sand drying and keeps the fruit off the ground, the tunnel holds the day's heat into the night and keeps the rain off the flowers, and together they make a winter on the Atlantic coast of Spain behave like a spring. The water goes on by drip from the first day, a few litres per square metre each day, with the fertiliser in it, and the fruit is picked from December until the heat of May makes it soft.

Everything else about the system follows from the calendar. The pickers are the plain's other import, tens of thousands of seasonal workers, many of them women from Morocco on contracts that return them home in June, housed on the farms and paid by the day, and the tunnels are their workplace for six months. The plants are thrown away at the end of the season and the plastic is rolled up, and some of it is recycled and some goes into the pines. The same plain now grows blueberries and raspberries under the same tunnels for the same supermarkets, on the same wells, and the berries that are not strawberries have taken the newer land. Morocco, across the strait, has copied the model on its own Atlantic coast, with water from an aquifer that is falling faster than Huelva's, and the winter punnet that is not from Spain is increasingly from there.

California

The other strawberry country is California, which grows about nine tenths of the berries eaten in the United States on a strip of coast from Watsonville to Oxnard, where the fog keeps the summer cool. The method is the same as Huelva's, raised beds under plastic mulch with drip tape, and the water comes from wells into coastal aquifers that have been pumped for a century, so that in the Pajaro and Salinas valleys the sea has moved into the aquifer behind the falling water table, and wells near the coast draw salt. The valleys are now under the state's groundwater law of 2014, which requires the pumping to be brought into balance over twenty years, and the growers are paying for recycled water from the towns' treatment plants, which the greywater article on this site describes, to keep the berries and push the sea back. The fruit is light in water; the aquifer under it is the heavy part.

What the punnet carries

A strawberry footprint is a small number attached to a sharp question, which is where the blue water was drawn and what else depended on it. The hundred and forty litres in a winter punnet from Huelva came out of the ground that Doñana stands on, at the end of a dry year, through a well that may or may not have had a permit, and the lagoon that dried in August is the other end of the pipe. A punnet in June from a field in Kent or Michigan is rain and a little river water in a wet season, and the question hardly arises. The fruit is the same. The month and the map are what decide the water.

A hundred and forty litres a punnet, a thousand wells, and a lagoon that dried for the first time anyone could remember.