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Review article - Peer-reviewed, 2021

Revisiting the original reasons for excluding inorganic fertilizers in organic farming-Why the ban is not consistent with our current scientific understanding

Kirchmann, Holger

Abstract

This paper reviews the original reasons of the organic farming movement for excluding mineral (inorganic) fertilizers. In this paper, their theories and decision criteria for excluding use of inorganic fertilizers in crop production were revisited. Original reasons for banning inorganic fertilizers were subjected to scientific scrutiny, which was not possible when they were formulated 50-100 years ago due to limited knowledge of the soil-crop system. The original reasons were as follows: Rudolf Steiner, the founder of biodynamic farming, played down the physical role of plant nutrients and pointed out "flow of forces" as being most important for soils and crops. Eve Balfour and Albert Howard, founders of the Soil Association in England, claimed that inorganic fertilizer increases the breakdown of humus in soil, leading to a decline in soil fertility. Hans-Peter Rusch, the founder of biological organic farming, considered inorganic fertilizers to be imbalanced products not matching crop composition and not in synchrony with crop demand. When testing these historical statements as scientific hypotheses, older and modern scientific literature was used for validation. Steiner's belief about the "flow of forces" has not be verified using current methodologies. The claim by Balfour and Howard that inorganic fertilizers accelerate soil organic matter decomposition is not substantiated by data from long-term field experiments on carbon and nitrogen cycling in soil-plant systems. The statement by Rusch that inorganic fertilizers supply crops inappropriately is difficult to uphold, as the composition, time, and rate of application and the placement of fertilizer in soil or on foliage can be fully adapted to crop requirements. In light of accumulated scientific evidence, the original arguments lack validity. The decision to ban inorganic fertilizers in organic farming is inconsistent with our current scientific understanding. Scientific stringency requires principles found to be erroneous to be abandoned.

Keywords

Steiner; Balfour; Rusch; view on nature; test of core statements

Published in

Outlook On Agriculture
2021, volume: 50, number: 2, pages: 107-115
Publisher: SAGE PUBLICATIONS LTD

Authors' information

Swedish University of Agricultural Sciences, Department of Soil and Environment

Sustainable Development Goals

SDG2 Zero hunger

UKÄ Subject classification

Soil Science

Publication Identifiers

DOI: https://doi.org/10.1177/00307270211020025

URI (permanent link to this page)

https://res.slu.se/id/publ/112536