Critical Decline of Earthworms from Organic Origins under Intensive, Humic SOM-Depleting Agriculture

[摘要] In view of recent reports of critical declines of microbes, plants, insects and other invertebrates, birds and other vertebrates, the situation pertaining to neglected earthworms was investigated. Entomological reports found the probable cause of general loss was lack of recruitment from surrounding fields (except for pest species). Earthworm decline under agricultural intensification compared to organic fertilizing is herein charted from several long-term agronomic trials, some operational >170 years. Relative biomass losses of –50–100% (with a mean of –83.3 %) match or exceed those reported for other faunal groups, thus earthworms are conclusively shown to be similarly depleted from their optima in agrichemical fields. Concomitant mean loss of SOC/SOM humus is –56.8% and soil moisture is reduced by –22.3%. Organic farming lessens humic degradation and topsoil erosion, conserves essential soil moisture and biota, and produces equivalent or higher crop and pasture yields (on average +17.8% in this study) at lower cost. Loss of earthworms adds weight for rational re-evaluation of viable means for food production compatible with environmental conservation (agroecology), hence various interlinked benefits of organic husbandry in terms of yields, soil restoration, biodiversity and economics are briefly discussed. Persistence with failing chemical agriculture makes neither ecological nor economic sense.

[学科分类] 土壤学

[关键词] megadrile earthworms;soil-fauna surveys;biodiversity loss;agro-ecology;humus