To meet the challenge of feeding a growing world population with minimal environmental impact, we need comprehensive and quantitative knowledge of ecological factors affecting crop production. Earthworms are among the most important soil dwelling invertebrates. Their activity affects both biotic and abiotic soil properties, in turn affecting plant growth. Yet, studies on the effect of earthworm presence on crop yields have not been quantitatively synthesized. Here we show, using meta-analysis, that on average earthworm presence in agroecosystems leads to a 25% increase in crop yield and a 23% increase in aboveground biomass. The magnitude of these effects depends on presence of crop residue, earthworm density and type and rate of fertilization. The positive effects of earthworms become larger when more residue is returned to the soil, but disappear when soil nitrogen availability is high. This suggests that earthworms stimulate plant growth predominantly through releasing nitrogen locked away in residue and soil organic matter. Our results therefore imply that earthworms are of crucial importance to decrease the yield gap of farmers who can’t -or won’t- use nitrogen fertilizer.
Continue reading “Earthworms Increase Plant Production”
On the International Day of Biological Diversity, Greenpeace’s Kumi Naidoo exhorts us to move away from our current farming system
On today’s United Nations biodiversity day, we are being asked to focus on small islands and their unique ecology and fragility in times of globally pervasive threats such as climate change.
But, the whole planet is a small island in the vast sea of space, capable of producing food for all as a consequence of rich biodiversity. That diversity is under threat, our actions can strengthen it or weaken it. Our agriculture systems can help mitigate climate change and feed us, or they can accelerate the change and contribute to hunger.
The food system we choose has a direct impact on which type of world we will have. It’s the difference between a field that hums and is robust with life, or one which is dusty, dry and dead. It’s the difference between a place where ecological farming has been used or where a cocktail of industrial chemicals has soaked into the soil where the same crop is grown, decade after decade.
Our current food and farming system is creating more and more of these dry, dead ends. It is agriculture characterised by three things: the industrial-sized growing of a single plant, or “monoculture”, genetically engineered crops, and repeated toxic chemical infusions of pesticides and the application of synthetic fertilisers. All of these harm people and the farming ecosystems they depend on.
Continue reading “Our Food System Affects Biodiversity: Do We Want Monocultures?”