The story

Vincent de Leijster & Roos van der Deijl
Photography by Tom Lovett

While the regenerative agriculture movement is gaining momentum on a global scale, transforming agricultural practice on the ground is not always as easy as it seems. Ecosystems are complex, so the efficacy of agricultural practices differs greatly between landscapes and climatic conditions. We need evidence-based knowledge that farmers can rely on to bring back balance with nature, increase ecosystem services, enhance yield, and, crucially, bring in a proper income.

Vincent de Leijster, currently an Impact Specialist at Wij.land, has spent 4 years researching precisely these topics. Before landing this role, he was a PhD researcher at the Copernicus Institute of Sustainable Development, Utrecht University. With his colleagues Dr Pita Verweij, Prof. Martin Wassen, and Dr Maria Santos, he investigated the ecological and economic aspects of sustainable land management in coffee plantations in Colombia and almond orchards in southern Spain. These studies provide valuable information for farmers on the ground.

This story outlines the practical implications of his research in the Altiplano Estepario in southern Spain. As the farms under study were almond orchards in a dryland Mediterranean landscape, the results are most relevant to these climatic and ecological conditions.

Compost is a win-win-win practice

Compost is the result of properly decomposed organic material (like manure, leaves, straw, and ashes). It’s a nutrient-rich, dirt-like material that can be used in agriculture in various ways to improve soil quality and stimulate crop growth. Because a lot of soils have been lost in the Mediterranean region due to excessive tilling, bare soils, and other harmful practices, compost can have an especially significant impact on soil fertility here.

Vincent’s research indeed found that compost can enhance soil fertility after only one year of usage. They saw that compost effectively improved multiple soil characteristics, such as biological activity and nutrient availability. This led to higher almond production and heavier and larger almonds.

In the dedicated Almond Chapter of the 4 Returns  Regenerative Agriculture manual, you can find more details about the specific contexts in which compost can have an impact, as well as the needs, costs, and risks. Do note: to tackle soil erosion and reverse land degradation, just applying compost will not be enough. You will need to combine it with vegetation cover.

Trees on terraces with compost at the La Solana farm in the Altiplano – photo by Tom Lovett

Vegetation cover can be good for the soil if implemented well

Vegetation covers are plants grown with the main purpose of covering the soil.  This can help to prevent soil erosion from rainfall, improve water infiltration, enhance biodiversity, and bring nutrients back into the soil. Vegetation cover sometimes includes cover crops, which can be sold for extra income.

Vincent’s research found that vegetation cover produces higher insect biodiversity, fewer pest outbreaks, and higher carbon storage in almond plantations. Unfortunately, there is also some bad news: the results showed that no-tillage management may reduce almond yield. However, the key here is how your vegetation cover is implemented. There are ways to stimulate greater ecological benefits from vegetation cover while reducing the negative impacts on production loss. Here are some tips on how to do so:

  • Use vegetation cover in alternating alleys (the area in between the crop lines).
  • Use strips of vegetation cover in the middle of these alleys, while keeping the rooting area of the crop barer.
  • Use vegetation covers in the same line as the almonds, while keeping the alleys mostly bare.
  • Use temporary vegetation covers (only in Autumn, Winter, and Spring), such as green manure.
  • Use vegetation covers in combination with compost. The potential of this combination was tested by CEBAS (Raquel Lujan Soto) and was found to be promising in terms of optimizing multiple ecosystem services.

To decide whether ground cover is the right practice for you, check out the almond chapter of this guide.

Regenerative almond orchard with ground cover – photo by Tom Lovett

Pollinators need to be protected on a landscape scale

Pollinators play a key role in maintaining a healthy ecosystem and providing essential pollination services to your crops. Unfortunately, agricultural intensification is pushing away pollinator’s habitats. How can you welcome these little heroes back to your farm? Interestingly, the results of Vincent’s research show the importance of doing this on a landscape scale.

In the area that was researched, there were more pollinators in areas with more natural vegetation. However, this was only true on a scale larger than an average farm’s size. This suggests that pollinators need to be protected on a landscape scale to be effective. So, collaboration is key here! Combine forces with your neighbours to collectively create habitats for pollinators by expanding and connecting the natural zones. The bees will be thankful and provide you with their pollination services.

Of course, it is still important to consider insect biodiversity on a farm scale. Logically, the natural enemies of pests stay close to their targets. The researchers found that fewer pests were found on farms with more vegetation. If they are provided with the right habitat, these insects will keep nasty pests away.

Pollinators on flowering almond in the Altiplano – photo by Tom Lovett

Profit could decrease in the short term, but there are ways to compensate

Can you make a proper income from regenerative (almond) farming? This is a critical question for all those farmers considering taking the plunge. Vincent’s research showed that vegetation covers may reduce almond productivity, but compost can subsequently improve productivity. Profits are expected to follow the same pattern. To minimise possible profit loss, make sure to combine vegetation covers with compost and apply them in different ways (as explained above). The researchers also investigated a few opportunities that may compensate for these opportunity costs:

Carbon credits and subsidy schemes

Carbon compensation currently has little potential in the Altiplano Estepario region. One problem here is carbon prices, which are generally low for landscape-scale restoration projects. But even at higher prices, the additional value is negligible. Mediterranean soils have a very low capacity for storing carbon. The effects of regenerative practices on soil organic carbon are in absolute numbers so low that carbon does not provide more than €30 per ha per year, which is not enough to compensate for yield losses in no-tillage and green manure farms. Payments for carbon schemes are, therefore, not interesting for this region unless uncommonly high prices are being paid.

Vincent advises focusing on other incentive systems, such as biodiversity credits or credits to stop or slow down erosion. There is also an important role for (local) governments to reward nature-positive practices instead. Farmers can help push this agenda by collaborating with the government’s organic certificate and subsidy schemes, aiming at adapting their criteria for almond plantations to include an incentive for vegetation covers.

Crop diversification

From experiences in other study locations, the researchers have found that crop diversification can improve both environmental and economic conditions. If vegetation covers would provide additional income from co-products, losses in almond production could be compensated. Examples are the combination of almonds with aromatic strips or with cereals (also known as agroforestry). To learn how to set up your cover cropping strategy, read this how-to guide (based on the South African semi-arid context).

Want to learn more?

Find Vincent’s full PhD research here.

This research focused primarily on the regenerative practices of composting, vegetation covers, creating habitat for pollinators, and crop diversification. There are many other regenerative practices possible. This manual by the Regeneration Academy and the Rock Group helps Mediterranean farmers with practical planning, design, and implementation of a regenerative system, including examples and learnings from existing regenerative farms. It includes a chapter specifically for almond and olive farmers.

Did these findings bring you some new insights? What else would you like to know that further research could investigate? Let us know in the comments!

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