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.
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Take a look at this amazing resource I’ve just discovered, it’s Dr Elaine Inghams lessons on the soil food web, as well as creating your own composts and compost teas/extracts. The information contained hereinafter is often behind a paywall.
“Elaine Ingham, Chief Scientist at Rhodale Institute came to Hawi, Hawai’i in July 2012 to deliver a 5 day seminar dedicated to studying, understanding, and improving our soil biology to assist in ecologically sound agricultural practices. This is where I got my introduction to the microscope and learned much of it’s importance. This was some of the best 30 hours of class ever, and I often re-watch this epic series to refresh myself and discover more as I tune my own magnification of understanding this microscopic wonderland.” – Drake of Natural Farming Hawaii.
This presentation consists of 18 videos containing a total of 26 hours of footage. For information purposes the audio quality is a little poor and the presentation slides are slightly out of focus.