The “Black Gold” Attracting More And More Farmers

Rafael Doñate and Marius Vintila are already on the trail of the “black gold”. The two Spanish farmers take advan­tage of the condi­tions in their home­town to make good profits in the truffle busi­ness. But what exactly makes the truffle such a deli­cacy and what does optimal cultivation on a truffle farm look like?

Truf­fles are fungi that grow under­ground. They are pecu­liar in that they grow in symbiosis with the roots of different trees like holm oaks (ever­green oaks), common oaks, walnuts or chestnut trees. In this agro­forestry envi­ron­ment, the fungus and the plant root grow together and mutu­ally benefit each other, forming what is known as a micor­rhiza. The mycelium of the fungus captures nutri­ents and water for the plant, and also protects it from certain diseases. And the plant in turn provides the fungus with sugars, amino acids and other substances it needs.

The Sume­rians and ancient Egyp­tians enjoyed these under­ground fungi and rated them highly. And pheasant with truffle was a favorite dish in ancient Greece. The Romans also relished truf­fles. The emperor Julius Caesar allegedly once said: “Take my legions and give me your truf­fles”. Nowa­days truf­fles are highly prized in cooking, for the aroma and flavor they lend to dishes.

The village of Sarrión in Spain is one of the areas with the biggest produc­tion in the world of black truf­fles, also called winter truf­fles. Most of them are exported to France, Italy, the US, Japan and other coun­tries. Thanks to the good prices farmers obtain for their truf­fles (€500/kg or £423/kg on average in 2023), the region’s economy has been revi­talised and the popu­la­tion has increased. “If it weren’t for the truffle crop, hardly anyone would live here,” says producer Rafael Doñate. “It would be depop­u­lated like other parts of the province. And yet not only has the popu­la­tion of Sarrión not dimin­ished, it has increased over recent years.”.

HARVESTING

Truf­fles are harvested by hand, from November to March, and since they cannot be spotted on the surface, truffle farmers are accom­pa­nied by trained dogs. The dog marks the place where the truffle is, and the farmer then digs it out with a special trowel. They are usually found at a depth of about 15 or 20cm.

We accom­pa­nied Marius Vintila to harvest this type of truffle with his dog Canoli, an English pointer with an excel­lent sense of smell. The dogs work two hours a day. When farmers truffle harvest, they gener­ally take three dogs with them, in order to be able to complete a six-hour working day. “Any breed of dog is good for truffle hunting,” says Marius. “But some are better than others; for example the Navarra sheepdog.” They train their dogs by giving them small pieces of truffle to eat. Once they like it, they take them out into the field with other more expe­ri­enced dogs who teach them to dig.

We are on one of the family estates. Marius’s father-in-law, Rafael, was one of the pioneers of truffle farming in this area of the Teruel province. He was one of the first to be brave enough to plant mycor­rhized holm oaks to obtain truf­fles. “They said we were crazy, but time has proven us right.” There are now hundreds of parcels of land, and thou­sands of hectares, devoted to this crop around Sarrión. “The crops grown here before weren’t very lucra­tive,” says Rafael. “The ground in this area is very stony, bad for cereal produc­tion, whereas for truf­fles it’s ideal.”

The first truffle farms in this area were estab­lished in the 1980s. Before that, people would harvest the truf­fles that grew wild in the nearby moun­tains.

On this two-hectare parcel, the holm oaks are 17 years old, and were planted with a
6x6m spacing pattern. Other farmers prefer 7×7 or 4x5m spacing patterns. Truffle farming calls for patience; mycor­rhized trees are planted, but they do not start to produce truf­fles until 10 years have passed. The trees are at their peak between the 12th and 20th year, and this is their most produc­tive period. Produc­tion then declines until the 30th year, when the truffle orchard is deemed to have completed its produc­tive cycle.

KEY ASPECTS OF CULTIVATION

Truffle growing is very labo­rious. “It isn’t just about planting and harvesting; we devote time to it throughout the year,” Marius tells us. After planting the trees, for the first five years, they hoe around the trunk to prevent grass from growing there. A tractor pulling a culti­vator tills between the rows of trees. “We till very super­fi­cially so as not to break any roots,” says Rafael. “We need a tractor that fits between the rows of trees. When the trees are small it isn’t a problem, but then they grow and we don’t want the tractor to brush against the branches, so we are inter­ested in more compact trac­tors.”

Pruning is also impor­tant, but it has to be “exactly the right amount, for there to be space when harvesting, and for the water from the micro-sprin­klers to reach them,” explains Rafael. Micro-sprin­klers are the most-used irri­ga­tion system on the truffle farms in the Sarrión area. Pruning waste cannot be burned, so it is ground up and the sawdust is buried beside the tree to hollow out the soil and facil­i­tate truffle growth.

The biggest problem they face is the lack of water. The best condi­tions for black truf­fles is snow, but because of climate change, snow­fall is increas­ingly sparse, as is rain­fall, and so the farmers water the trees every 14 or 20 days, even in winter. The water is drawn from wells that are over 250m deep. “We make very large invest­ments to extract the water, but we do mone­tise them,” Marius indi­cates.

All crops have their pests, and this one is no excep­tion. Wild boar love truf­fles, and rabbits adore the shoots of the young plants, which is why all the orchards are fenced off. But the pest that worries the truffle farmers the most is the truffle beetle (Leiodes cinnamomea). The larvae of this beetle feed off the young truf­fles, digging out galleries, hindering their growth and accel­er­ating their matu­rity. On occa­sions, the crop loss can be in excess of 50%. The best way farmers have found of combating this beetle is by using baited traps.

Holm oak orchards for truffle produc­tion in the Sarrión area.

Rafael Doñate (left) and Marius Vintila (right) on one of the parcels they farm.

Very shallow tilling takes place in order to elim­i­nate weeds without damaging the roots of the holm oaks.

CURIOUS FACTS

Harvesting is the most time-consuming task. “The toughest, most diffi­cult thing is hunting the truf­fles,” says Marius. “This winter there were days when we worked at 7°C below zero.” They are removed by hand, one by one and farmers have to come out on numerous days with different dogs. “A single dog can’t get all the truf­fles. We go over the same parcel several times with different dogs,” he explains.

The size, shape and weight of the truf­fles is vari­able. In general, the greater the weight, the higher the price the truffle fetches. However, impor­tance is also attached to shape. Those held in the highest esteem are the largest ones with a more spher­ical shape. To ensure the truf­fles grow with this rounded silhou­ette, peat is added to the soil. Like sawdust, this helps the soil to hollow out, and gives the truf­fles more space in which to develop.

You can tell if a tree is a truffle tree at a glance, because there is a circle on the ground where no plants grow. This area is said to be ‘burnt’. If weeds grow, ie, if the ‘burnt’ area does not appear, this is an indi­ca­tion that the tree will not yield any truf­fles.

“In the truffle busi­ness, two plus two doesn’t make four,” Marius tells us. “We purchase all of the mycor­rhized plants from the nursery, and we apply the same cultivation tech­niques in all of our land parcels. However, there are trees that will yield truf­fles every year, trees that will do so in some years but not others, and other trees that never produce any truf­fles.” And the biggest tree does not neces­sarily yield more truf­fles. A small tree can produce more truf­fles than a larger one, notes Rafael. “Nature never ceases to surprise us.”