Trees and Soil Health

According to the United Nations, 90% of Earth's soils could be degraded by 2050. Planting trees and cover crops is a way to bring land under shade and enriching the enriching the soil through plant litter and animal waste.

Save Soil's THREE PRONGED STRATEGY TO REVITALIZE AGRICULTURAL SOIL (Presented at UNCCD COP 15)

1) Incentivize farmers to increase organic matter.

2) Make carbon credits accessible to farmers.

3) Preferential marketing for produce from soil with higher organic matter.

Why Save Soil?

52% of the world's agricultural soil is already degraded.

By 2050, nearly 90% of Earth’s soils could be degraded, according to the United Nations. What does this mean for us? Soil, the foundation of life on land, is losing its vital organic matter—plant waste, animal remains, and microorganisms. Without this, healthy soil transforms into dry, lifeless sand. While arid regions can support certain ecosystems, they cannot provide food for the 8.2 billion people on the planet, a number projected to grow to 10 billion.

Healthy soil is essential for growing nutritious food, supporting plant and animal life, regulating water flow, filtering pollutants, and providing stability to ecosystems. In fact, 95% of the food we eat comes directly or indirectly from soil. However, 52% of the world’s agricultural soils are already degraded, and the consequences are becoming increasingly dire.

The Role of Trees in Restoring Soil Health

As we plant a tree on SDSU campus at the Hello Walkway Garden on November 18th, 2024, it’s important to understand how trees and soil work together to sustain life. Healthy soil supports thriving trees, and trees, in turn, help replenish and protect soil. Planting trees combats soil erosion, enhances fertility, improves soil quality, and reduces the risk of natural disasters like floods and landslides by increasing the soil’s ability to retain water.

It takes 200 to 400 years to build a centimeter of soil (John Innes Centre). Forests are nature’s soil-builders.

Trees create new soil through physical and biological processes.
Tree roots:
- Penetrate rock layers, breaking them apart.
- Release nutrients from the rocks into the soil.
Organic materials from fallen leaves and decomposing plants enrich the soil.
Roots improve soil structure by:
- Promoting aeration.
- Enhancing drainage.

Source: OneTreePlanted

Combating Soil Erosion with Trees

Tree cover significantly slows soil erosion, a process that is accelerating due to deforestation and land degradation. Trees shield soil from erosive forces like wind and rain. Their roots anchor the soil, reducing runoff and stabilizing topsoil. By intercepting rainfall, trees prevent "splash erosion," where raindrops dislodge soil particles. They also help the soil absorb water more efficiently, reducing surface runoff and nutrient loss.

Source: OneTreePlanted

Trees and Soil Fertility

Trees contribute to soil fertility in several ways. They add organic matter, promote microbial activity, and help break nutrients into forms that plants can easily absorb. Their roots draw nutrients from deep soil layers to the surface, enrich the topsoil, and reduce nutrient loss through leaching and erosion.

Source: OneTreePlanted

A Real-World Example: Cauvery Calling

Learn More

Cauvery Calling is an ambitious ecological initiative aimed at revitalizing the Cauvery River basin in India. The project focuses on agroforestry, encouraging farmers to plant over 2.4 billion trees on private farmlands in the basin. This approach not only helps restore river flow and groundwater levels but also plays a critical role in improving soil health and increasing farmers’ incomes.

Key benefits of the initiative include:

Improved Soil Health: Tree planting replenishes organic content in the soil, boosting its fertility and structure.
Enhanced Water Retention: Trees improve the soil's ability to hold water, reducing runoff and erosion, which aids in revitalizing the river.
Increased Agricultural Sustainability: By incorporating trees, the agroforestry model supports biodiversity, mitigates land degradation, and provides additional income streams for farmers through timber, fruits, and other tree-based resources.