People around the world have discovered clever ways to farm in tough conditions. Their land could be too dry, too wet, too hot, or prone to insects or damaging storms. If the land is too steep, people might try terrace farming. Cultures in Peru, Japan, the Philippines, Mexico, the Mediterranean, East Africa, Yemen, and China have all independently created the concept of terracing.
Conventional farming removes all trees and plants to replace them with a crop, such as wheat. This sort of farming fails on steep slopes because it creates erosion and landslides.
Erosion is the process of soil wearing away due to water or wind. Without trees and other vegetation to slow down water, rain storms cause significant erosion on the land. The water has less resistance as it runs down the hill, so it can run faster and pick up more soil as it moves. This erosion carries vital nutrients and productive soil downhill, away from the farmland. Over many years, this sort of erosion can cause a slope to become infertile.
Additionally, a de-vegetated slope is more prone to mudslides if it becomes waterlogged from lots of rain. A mudslide could ruin an entire years crop and make the land much harder to farm in the future. Yikes!
Terracing turns a slope into level, benched out steps by moving soil and creating retaining walls. This restructuring allows un-farmable hillsides to become stable, productive farmlands. Some typical crops grown in terraces include barley, wheat, potatoes, corn, tea, olive, grape vines, coffee, and rice. A terrace is typically about 2-3 meters wide and 50-80 meters long. Some terraces flood with rain water, such as those used to farm rice.
A terrace usually has one outlet for water to drain into the terrace below. This lower terrace stops the water and prevents it from gaining enough speed to cause erosion. This way, the water deposits any soil in the downhill terraces as it slows down.
Science has validated the millenia-old tradition of terrace farming. When growing potatoes in Canada, researchers found that terracing on a steep slope reduced erosion by 20-1. In Japan, terracing even reduced erosion compared to the same landscape planted with trees!
In China, terracing on a shallow slope decreased soil nutrient loss by 90%. It also decreased the amount of soil lost by 60-90%, and increased general soil moisture by 21%. In arid regions of Ethiopia, terraced farms produced up to 33% more food during drought years compared to conventionally farmed slopes. Terracing increases soil moisture because rain to soaks into flat areas rather than running downslope. Many dry regions will become more arid with climate change. This means terracing is a climate resilient solution.
Culturally, terrace farming preserves indigenous techniques from around the world. An area in the Philippines received the first “Living Cultural Landscape” designation by UNESCO. There, cultures wove the farming technique into their land and traditions for centuries.
Machines such as tractors and chemical appliers aren’t used on terraces because of the structures’ highly irregular shapes. This lack of mechanized labor promotes traditional ways of living, such as farming small pieces of land with hand tools. Without machines and chemicals, terrace farming has a much lower carbon footprint than conventional farming.
Terrace farming certainly has difficulties, as well. Terracing requires massive inputs of labor. Creating a terrace requires moving tons of soil and building hundreds of meters of stone walls, typically by hand. Once established, terraces need routine maintenance to continue functioning. Historically, labor was readily available in rural, mountainous areas of the world. Currently, however, young, able-bodied people move to cities to become educated and work higher paying jobs. Older women and men maintain the terraces, instead. This lack of labor results in less upkeep. Once a terrace is abandoned, the retaining walls crumble and nearly all of the productive topsoil is lost to wind and water erosion.
From a natural point of view, steep slopes are some of the only areas spared from human manipulation. In places where all flat areas and small hills have been deforested, steep slopes are important for the remaining wildlife and plants. If terrace farming increases, these remnant ecosystems will inevitably be lost.
Terracing is not only applicable to farmers. Many homeowners build terraces if their yard is on a slope! Homeowners can then grow gardens and fruit trees, or create pleasant sitting areas where previously they had an unusable slope. Garden terraces also make for beautiful landscapes. And as an added plus, if you grow berries on terraces you can pick them from the terrace below without having to bend over!