Kindergarten students are taught that earthworms are allies of the farmer. But how reliable the harmless invertebrates really are when it comes to cultivation? A recent study claims to have solved this question and its findings will blow your mind!
Earthworms contribute to the harvest of 140 million tonnes of food each year, the report shows. To understand how enormous it is, put it this way. Russia, the largest country in the world by area, produced 150 million tonnes of food last year and is expected to produce 120 million this year. If earthworms were to be considered a country, they would have become the fourth-largest global producer of food grains!
In another interesting simplification, the Guardian put it this way. Earthworm activity contributes to one of 15 slices in every bread loaf baked...
Published by Steven J. Fonte, Marian Hsieh and Nathaniel D. Mueller of Nature Communications, the study said that earthworms contribute to 6.45% of global grain harvests. Their contribution to the cultivation of legumes like chickpeas, lentils and soybean were also included in the study. "Our findings indicate that earthworms contribute to roughly 6.5% of global grain (maize, rice, wheat, barley) production and 2.3% of legume production, equivalent to over 140 million metric tons annually," the report read.
How do earthworms help cultivation?
Various studies also report that earthworms can convert barren land into fertile land and increase agricultural output. According to the New South Wales Government's Department of Primary Industries, earthworms feed on plant debris (dead roots, leaves, grasses, manure) and soil. Their digestive system concentrates the organic and mineral constituents in the food they eat, so their casts are richer in available nutrients than the soil around them. Worm bodies decompose rapidly, further contributing to the nitrogen content of the soil.
The extensive channelling and burrowing by earthworms loosens and aerates the soil and improves soil drainage. Soils with earthworms drain up to 10 times faster than soils without earthworms.
The research was reportedly done by analysing and overlaying maps of soil properties and crop yields with a global atlas of earthworm abundance.
To be taken with a pinch of salt
However, the researchers are well aware of the shortcomings of their findings and called for further study.
"While the effect of earthworms is notable, we suspect that other soil biota may be equally as important and that further study is needed. Also, to be clear, we do not advocate for the widespread inoculation of earthworms...Instead, we suggest investment in continued research and promotion of agroecological management practices that enhance entire soil biological communities, including earthworms, so as to support a whole range of ecosystem services that contribute to the long-term sustainability and resilience of agriculture," the report's conclusion read.