[Smart Farmers] Although “earthy”, “rich”, protecting the world in the soil

Editor’s Note:

The report of the 20th CPC National Congress emphasized that "we should consolidate the foundation of food security in all aspects" and "implement major biodiversity protection projects". What is the intrinsic connection between building a strong agricultural country and agricultural biodiversity? How to balance food security and sustainable agricultural development? What is the current status of agricultural biodiversity in my country? How to protect agricultural biodiversity? "Five grains and six livestock" and "one meal and one vegetable" are all topics we care about. Science Popularization China Smart Farmers has launched a series of popular science articles. Welcome to follow.

On February 13, the "Opinions of the CPC Central Committee and the State Council on Doing a Good Job in Comprehensively Promoting Key Work for Rural Revitalization in 2023" was released. The document proposed a number of land protection measures, including "strengthening the protection and use control of cultivated land" and "severely cracking down on illegal digging of black soil, electric trapping of earthworms and other soil-damaging behaviors." Soil biodiversity is essential for the production of food and other agricultural products. How can we protect and use it to improve food security and nutrition?

Soil biodiversity

Land is the life of farmers, and the relationship between plants and soil is like the relationship between people and food. Plant nutrition comes directly from the soil. In the importance of biodiversity to agriculture, we mentioned that food and agricultural biodiversity not only refers to all wild and domesticated plants and animals that can provide food, feed, fuel and fiber, but also includes a large number of organisms that support food production through ecosystem services, that is, the diversity of related organisms. And organisms that can contribute to soil fertility are also related organisms.

A Tanzanian woman hoeing a field. Photo © Scott Wallace/World Bank

You probably can't imagine how many organisms choose soil as their home! Soil contains countless organisms, such as earthworms, ants, termites, bacteria, and fungi. In fact, a handful of typical garden soil contains billions to hundreds of billions of tiny soil microorganisms.

Functional diversity of soil biomes

What do soil organisms contribute to soil health? Together, these tiny organisms provide a wide range of services to their ecosystems, such as improving water intake and storage, preventing erosion, improving plant nutrition, and breaking down organic matter.

In addition, soil biodiversity indirectly affects the environment in many ways. For example, it helps control the occurrence of pests and diseases in agricultural and natural ecosystems, and can also control or reduce environmental pollution. Studies have shown that soil is the second largest carbon pool after forests, and some soils, such as peat, actually store more carbon per hectare than forests.

Schematic diagram of soil animal classification based on body width. Image from the Chinese Society of Soil Science

Plant roots are also soil organisms because they have a beneficial symbiotic relationship and interact with other soil organisms. They prevent soil erosion, help with drainage, and prevent the soil from becoming too wet. Conversely, they help retain moisture in the soil when it becomes too dry. Roots also help in the formation of soil by breaking down rocks into small pieces that eventually become soil.

Conservation of soil biodiversity

Today, the diversity of soil organisms is being destroyed. Overgrazing, vegetation clearing, wildfires and poor irrigation management, and the conversion of grassland or forest to cropland all lead to rapid loss of soil carbon. Urbanization and soil closure, such as land cover for housing, roads or other construction projects, also pose a threat to it.

Soil quality refers to the comprehensive ability of soil to accommodate and purify pollutants, maintain and ensure the growth of green plants, and meet other reasonable human needs. Soil biodiversity plays an important role in maintaining soil health, ensuring sustainable soil use, and regulating ecological security.

Rich and stable soil biodiversity is conducive to maintaining soil fertility, preventing and controlling soil-borne diseases, promoting agricultural production, and ensuring product quality. In addition, from the perspective of direct biomass production, the large fruiting bodies of some soil fungi can also be eaten or used as medicine. Secondly, soil biological germplasm resources can also play a key role in repairing polluted environments, especially in soil remediation, water management, and solid waste treatment. Bioremediation technology that uses microorganisms to decompose toxic and harmful substances is recognized as a valuable method for treating large areas of pollution.

Keeping soil healthy and improving ecosystem services requires a collaborative effort. That includes farmers and the organisms that live in the soil. For example, creating and maintaining healthy soil in an agricultural ecosystem requires a collaborative effort between farmers and worms. Small organisms such as worms burrow into the soil, aerating it so water can percolate and reach the roots of plants. Worms also digest dirt, old leaves, and dirt debris from healthy soil, recycling it into nutrients that nourish existing plants. In the process, worms provide a very important ecosystem service, aided by organic matter, including old leaves and plant debris, that they would not otherwise be able to provide.

Farmers also have a role to play in ensuring that the soil remains healthy and fertile. Farmers must carefully decide what type of farming practices they use so that the soil environment continues to provide ecosystem services. In agricultural ecosystems such as farmlands, farmers can leave organic matter on the ground as mulch, rather than collecting and processing it, so that it provides organic matter to worms, which then convert it into nutrients that feed the farmer's crops.

Schematic diagram of measures to protect farmland soil biodiversity. Image from the Chinese Society of Soil Science

Although much progress has been made in the study of soil biodiversity, human understanding of soil biodiversity is still limited, and basic questions such as how many species of organisms exist in the soil cannot be clearly answered. However, protecting soil biodiversity and the ecosystem services it provides are vital to global ecosystem security and are urgent!

Please lend a hand to protect soil biodiversity by improving soil habitats, reducing disturbance to the soil, and protecting soil biodiversity systems, so that healthy land can make a greater contribution to ensuring food security.

Produced by: Popular Science in China to Benefit Farmers

Producer: Guangming Online Science Department

Author: Liu Yadan, Research Fellow, National Chief Scientific Communication Expert, former Assistant Secretary-General of the Chinese Society of Fisheries, and Assistant Secretary-General of the China Rural Professional and Technical Association

Review expert: Pan Xiaofu, senior engineer, Kunming Institute of Zoology, Chinese Academy of Sciences

Planning: Wu Yuetong, Jiang Nan