Earthworms, threatened by intensive agriculture, contribute "significantly" to agricultural production, playing a role in about 6.5% of global cereal production, according to a study published on Tuesday.
"Worms contribute to around 6.5% of global cereal production (corn, rice, wheat, barley) and 2.3% of legumes, equivalent to more than 140 million tons per year," say researchers. , based in the United States, in an article published in the journal Nature Communications.
The "contribution" of worms is defined by researchers as the percentage of agricultural yield made possible by them.
Its positive role for soil health and plant growth was already well known. Their galleries allow water to infiltrate, participate in the recycling of nutrients to feed plants through their excrement and even help the production of hormones that facilitate plant growth.
But the scientists who carried out the study sought for the first time to quantify its contribution to agricultural production. To do this, they analyzed recent maps on the presence of worms, data on agricultural production and previous studies on soil productivity based on the presence of these invertebrates.
The authors specify that the contribution of earthworms is even greater in Southern countries, contributing to 10% of cereal production in sub-Saharan Africa and 8% in Latin America and the Caribbean.
They point out that their results, although they are "encouraging" and suggest a possible improvement in agricultural productivity by better caring for life in the soil, are also plagued by methodological "uncertainties."
In conclusion, the authors suggest promoting agroecology practices that preserve the life of the soil and especially that of earthworms.
The latter are threatened by intensive agriculture, with massive recourse to chemicals and regular tillage.