Earthworms: Soil Improvement and Crop Yields

• Earthworms enrich and improve soil.
• They boost crop yields and protect plants from harmful microplastics.

Impact on Food Production

• Earthworms are responsible for 6.5% of global food production annually, which is about 140 million tons.
• This amount is comparable to Russia's annual grain harvest, which is the world's fourth largest.

Research Methodology

• A research team from Colorado State University (CSU) surveyed earthworm populations, soil properties, and crop yields worldwide.
• The researchers focused on rice, maize, wheat, barley, soybeans, and peas.

Impact in Developing Countries

• Earthworms increase grain yields by 10% in Sub-Saharan Africa.
• They increase grain yields by 8% in Latin America.
• Farmers in these regions rely more on earthworm-rich organic matter due to less access to fertilizers and pesticides.
• Managing soils sustainably can better harness biodiversity and produce more sustainable agroecosystems.

Ways Earthworms Help Plant Growth

• Burrowing creates channels that loosen and aerate the soil.
• Allows water to drain from the surface and be stored underground.
• Constant movement helps churn the soil’s organic matter.
• This makes the nutrients more available to plants.

Protection from Microplastic Pollution

• Scientists at Japan’s Nankai University found that earthworms can protect plants from microplastic pollution.
• Tomato plants thrived in soil contaminated with tiny plastic particles when earthworms were present.
• The plants were also able to repel common plant-eating bugs.
• Earthworms help boost the tomato plants’ immune systems, making them more resilient to environmental changes.

Earthworm Facts

• They have segmented bodies with sleek and slimy skin.
• More than 7,000 kinds of earthworms exist.
• Earthworms can be found in most temperate and tropical soils.
• Earthworms range in size from 1 inch to 5.9 feet.
• The South African giant earthworm can reach 21 feet long; it was discovered in 1967.

Role as Decomposers

• Earthworms eat mouthfuls of soil containing rotten plants and roots.
• Earthworms are decomposers as they eat dead plants.
• Earthworms consume their own body weight every day.

Impact on Soil and Nutrients

• Worm castings function as a beneficial fertilizer.
• Soil would have fewer nutrients if earthworms disappeared.
• Plant growth relies on nutrients from worm castings.

Soil Structure

• Earthworms live in the top layer of soil but can dig down almost 6.5 feet.
• Digging and tunneling loosens the soil, increasing air, water, and organic matter.
• Soil would become compacted and dry without earthworms.

Water Absorption

• Earthworm tunnels allow rainwater to soak into the ground.
• Compacted soil wouldn’t absorb much water without earthworms, leading to frequent flooding during heavy rain.

Food Chain

• Earthworms are an important part of the food chain.
• Animals such as robins, foxes, toads, centipedes, and crayfish eat earthworms.
• Without earthworms, the entire food chain would collapse, with animals that eat earthworms disappearing first.

Worm Observation Experiment

• Explore outside when it rains and find a place where there is soil and worms.
• Using a magnifying glass, identify the worm's head and tail.
• Worms eat dead plants, locate any food source for worms to eat.
• Worm castings look like little black footballs.