Poppies, dandelions, leeks, fennel, nettles, asparagus, chamomile, olive groves or borage have traditionally been plants that have accompanied olive trees in the countryside. Many have been eaten, others were used for medicinal purposes, there are some that are fodder, others that fix nitrogen or even act as fungicides or insecticides. They are the weeds (wild plants that grow in crop fields) that, in any case, improve the structure and fertility of the soil, the true capital of the farmer, prevent erosion and increase biodiversity and its ecosystem services for agriculture.
With so many benefits, how then can they be called ‘weeds’? To eradicate such an unfair and mistaken expression, the LIFE Olivares Vivos project, coordinated by SEO/BirdLife, has launched the publication Good ‘weeds’ of the olive grove, together with the video Plant cover in the olive grove. Educational materials that aim to demystify such prejudices and perceptions about weed plants and inform olive growers of the real benefits derived from proper management of the herbaceous cover.
Coinciding with spring, when the herbaceous cover is controlled in olive groves, this publication analyzes the pros and cons of the different herbaceous cover management methods, so that farmers can decide which is the most appropriate management for their crops. farms. Similarly, it also shows how the perception around these herbs is changing, from the relentless fight that most olive growers have traditionally had against herbaceous covers, to the current recognition of the benefits they provide.
Plants as allies
Properly managing the herbaceous cover in the olive grove offers a whole series of advantages that range from the most obvious, such as the reduction of erosion, the natural fertilization of legumes (which fix atmospheric nitrogen in the soil) or the maintenance of the biodiversity, to others less known. Among the latter, the publication highlights the ecosystem services generated by weed plants related to the control of pests and diseases of the olive grove. For example, the presence of the olive grove (Dittrichia viscosa) in unproductive areas of the olive groves increases the density of predators of the olive fly larvae (the main pest of the olive grove and which causes significant damage to the production and quality of the olive oil). of olive), or the benefits of cruciferous plants such as white mustard (Sinapis alba) or dandelion (Diplotaxis virgata), which act as biological fumigators of the fungus Verticillium dahliae, which causes verticillium wilt and is killing thousands of olive trees.
Experiential testimonials
Some benefits that are endorsed in the testimonies of olive groves and olive growers who participate in the LIFE Olivares Vivos project and who tell how they have been changing the management of their green roofs, progressively reducing the use of herbicides to embrace other more sustainable management, such as clearing or, in some cases, grazing.
But apart from the crop itself and the olive grower, these testimonies claim that an olive grove with a well-managed herbaceous cover provides environmental services to society that should be rewarded. Erosion control, biodiversity conservation or the fight against climate change (the soil of an olive grove with herbaceous cover sequesters twice as much CO2 as another with bare soil) are services that these olive groves provide to human health and the environment. environment, and that should be taken into account in agricultural policies and in the appreciation of the added value of their oils by consumers.
From popular food and food for the poor, to haute cuisine
This publication also deals with the importance of these plants in rural culture, their uses and the experiences of some people who got to know multifunctional olive groves, which yielded much more than olives. The unfairly called "weeds" took away hunger in times of scarcity, and were common in the kitchen of the rural world. This is how Aurelia, Antonio, Manuel, Carmelo tell it, for whom the use of plants as food formed part of their lives. An almost extinct use and now claimed by prestigious chefs, who have discovered a culinary treasure in the "weeds".
Likewise, this publication includes a list of species that have traditionally grown in olive groves and have been used for food or medicine. Plants as common and appreciated as wild asparagus or wild chard, as well as chamomile or poppy, and which are now difficult to find in olive groves due to agricultural intensification.
“With Good ‘bad’ herbs we intend to promote this change in the olive grower’s vision towards weed plants and invite those who have not yet done so to follow the path that a few took years ago, to which many other farmers are joining. increasingly satisfied with the herbaceous covers of their olive groves. With the available knowledge, and as science has shown, cultivating olive groves keeping the soil bare all year round, abusing the use of herbicides or tillage, is an outdated and outdated model of olive growing, because it is unsustainable”, explains Jose Eugenio Gutiérrez, coordinator of the LIFE Olivares Vivos project and delegate of SEO/BirdLife in Andalusia.
Recovering biodiversity is feasible
All this information is supported by the article "Moderation by the landscape of the effects of herbaceous cover management on olive grove biodiversity: implications for the conservation of biodiversity at a regional scale", published in the journal Agriculture, Ecosystems and Environment and in which, through research carried out by the University of Jaén, the Experimental Station for Arid Zones of the CSIC and SEO/BirdLife, within the framework of LIFE Olivares Vivos, extremely interesting conclusions have been reached for the future of the olive grove and its biodiversity. Among them, it should be noted that, based on the data analyzed in the set of demonstration olive groves that participate in this LIFE project, to efficiently recover biodiversity in the olive grove, the proper management of the vegetation cover and the restoration of unproductive areas are key. Feasible, economic actions that bring profitability to the crop, as is being demonstrated thanks to Olivares Vivos.
