Small-scale Terraced Agriculture Protects the Climate and Environment

30 April 2021, by Katharina Heider

Photo: UHH/CEN/K. Heider

My gaze wanders down the valley. It comes to rest on a labyrinth of fruit trees, which, together with beds of vegetable and herbs, creates seemingly endless rows of green. That’s how diverse some of the gardens on the hills of the Ricote Valley in southeast Spain can be. For centuries, smallholders have cultivated terraced fields here, using sophisticated irrigation systems. The traditional fields are species-rich and resilient – and offer a climate-friendly alternative to industrial agriculture. However, in many abandoned gardens, the green has disappeared.

Why do people give up their land? I’ve investigated this question in detail. At Universität Hamburg’s Center for Earth System Research and Sustainability, I studied these terraced fields from 2016 to 2019. How many are still cultivated? What do the people living there have to say?

In the first step, I located the agricultural terraces using land-register data and a laser-based digital elevation model of the Earth’s surface. On the basis of how level the surface in the model was, I was able to determine where there were terraces and where there was rugged terrain.

In the second step, I used satellite images to determine how the terraces were used: I created a vegetation index that showed to what extent the areas were covered by plants and how healthy the latter appeared to be. By doing so, I was able to determine which fields were irrigated.

In the next step, I combined the identified terraces and their forms of use to calculate the total cultivated area. The result was surprising: the larger the plot of land, the less likely it was to be cultivated. In 2019, ca. 76 percent of the small fields on the terraces, but only 57 percent of the large ones, were cultivated. But there was also a promising trend: from 2016 to 2019, the proportion of uncultivated fields fell by roughly 16 percent. But that also means: in the end, ca. 40 percent of the terraces weren’t cultivated at all. Why not?

The final step in my study, in which I spoke with experts and locals, offered insights here: climate change, water shortages and soil degradation due to intensive farming were the main environmental factors when it came to land abandonment in the region. However, from the conversations, it soon became clear that social and economic factors were even more important. As a result, the steep slopes and the local inheritance rules, which divide the land between siblings, have led to a fragmentation of the area. Furthermore, the locals claimed that farming was an unattractive option for young people, due to the amount of labor involved and low crop prices. Nevertheless, those in the next generation feel a strong emotional connection to the land and don’t want to sell, even if they don’t farm it. Therefore, many areas are no longer cultivated.

However, my analysis also revealed that farming smaller fields appears to work well. As I discovered, many families don’t make their living from agriculture alone, which allows them to compensate for price fluctuations. Despite this, the competition from industrial agriculture is omnipresent. Further, the Ricote Valley can’t rely on farming subsidies, since small fields aren’t eligible for support. But helping these smallholders would be an important contribution to preserving the variety and resilience of this agricultural landscape.