This inconspicuous little creature may be a "great contributor" to food production

Earthworms, also known as earthworms, are terrestrial invertebrates of the class Oligochaeta of the phylum Annelida. There are more than 3,000 species of earthworms in the world. They do not like light and prefer to live in dark and humid soil. Earthworms constantly dig holes in the soil, turning organic matter and deep soil in the soil to the surface layer, which not only transforms the structure of the soil, but also improves the air permeability, fluffiness and water storage capacity of the soil, and can also help the roots of plants to better penetrate the soil and absorb nutrients.

Earthworms are saprophagous animals. While they obtain decayed plants and other organic matter from the soil, their excrement is also an excellent fertilizer with complete nutrients, which enriches the soil. During the movement of earthworms, the excrement left in the pores can form water-stable aggregates with the soil, which helps to enhance the aeration and water-holding capacity of the soil and prevent the soil from becoming compacted.

Earthworms regulate soil microbial biomass and soil biological communities, and are the main drivers of soil organic carbon, nitrogen, phosphorus, sulfur and other element cycles and soil mineral decomposition. Earthworms play a special role in soil improvement, pollution elimination, ecological environment protection, material circulation promotion and biodiversity maintenance.

Image source: pixabay

However, the contribution of earthworms to global agricultural production has not been quantified. In order to assess the impact of earthworms on the production of important crops worldwide, Steven Fonte and colleagues at Colorado State University in the United States conducted a meta-analysis of maps and data on earthworm abundance, soil properties, and crop production. They combined the different responses of earthworms to yields under different crop types, soil properties (texture, pH), nitrogen fertilizer inputs, and different earthworm abundance levels with the latest earthworm distribution and abundance maps and global soil, management, and crop data layers to estimate the potential contribution of earthworms to global agricultural production.

The results showed that earthworms contribute about 6.45% of the global production of cereals (including corn, rice, wheat and barley), or about 128 million tons. In addition, earthworms also contribute 2.3% of the global production of legumes (including soybeans, peas, chickpeas, lentils and alfalfa); cereals and legumes together contribute more than 140 million tons of food each year.

When considering the impact of earthworms in different regions, the study found that the relative impact was greatest in Sub-Saharan Africa , where earthworms were estimated to contribute about 10% of total cereal production and 3.2% to pulse production. This was closely followed by Latin America and the Caribbean , where about 8% of cereal production and 3.1% of pulse production could be attributed to earthworms. In the Global South, the greater impact of earthworms on yields appears to be related to generally lower soil pH, higher clay content, and lower fertilizer inputs, all of which suggest that earthworms provide a greater relative benefit to plant growth.

This study is the first attempt to quantify the contribution of earthworms to global agricultural production. The research results were published in the recent "Nature Communications" under the title "Earthworms contribute significantly to global food production".

Soil biomes have great potential in supporting food production and a range of other ecosystem services. Earthworms, in particular, are important soil ecosystem "engineers". The authors of the paper suggest supporting a range of ecological measures that contribute to long-term agricultural sustainability and soil resilience, such as enhancing the entire soil biome, including earthworms. However, the authors do not advocate the widespread introduction of earthworms in areas where they are currently absent, as the introduction of new species would have adverse ecological consequences for the area.

References

[1]https://www.nature.com/articles/s41467-023-41286-7?utm_medium=organic_social&utm_source=zhihu&utm_campaign=CONR_PF020_ENGM_AP_CNCM_002EA_weeklyS

Planning and production

Author: Zeng Xinyue, popular science creator

Review | He Huyi, Researcher at the Institute of Economic Crops, Guangxi Academy of Agricultural Sciences

Editor: Zhong Yanping and Qi Yuan (Intern)