Introduction
Advocating for an integrated plant nutrition approach
Organic farming is a farming system that promotes, among other practices, the use of organic fertilizers. Organic matter is an essential component of healthy soils, and all sound farming practices integrate and allocate available organic materials to maintain or improve soil fertility. However, because organic fertilizers are low in nutrient content, high application rates are needed to meet crop nutrient requirements.
In many countries, particularly in developing countries, the availability of organic sources of fertilizers is simply insufficient for crop needs, partly due to competitive uses such as energy production. Moreover, the nutrient content, composition and release rate of organic fertilizers is variable and unpredictable and, therefore, it is extremely difficult to ensure a steady supply and the correct balance of all the essential elements for healthy plant growth. Nutrient imbalances and declining soil fertility usually show up only several years after conversion to organic farming systems, due to progressively declining residual nutrients in the soil.
Independent scientific studies show that combining inorganic and organic sources of plant nutrients is a beneficial option for the crop and soil system and hence can be of great benefit to both farmers and the environment. Combined together, organic and inorganic nutrient sources can improve soil fertility, enhance soil organic matter content and limit both nutrient and soil losses. This integrated plant nutrition approach is an appropriate strategy for effective and responsible plant nutrition.
Promoting science-based requirements on fertilizers
The use of some inorganic sources of plant nutrients in organic farming systems is recognized by the International Federation of Organic Agriculture Movements (IFOAM) and Codex Alimentarius (a joint FAO/WHO intergovernmental body in charge of setting minimum international standards and guidelines that apply to food products).
According to IFOAM, substances to be added to the list of products authorized for organic farming shall be “essential for achieving or maintaining soil fertility or to fulfill specific nutrient requirements; the ingredients are of plant, animal, microbial or mineral origin which may undergo physical (mechanical, thermal), enzymatic or microbial (composting, digestion) processes; their use does not result in, or contribute to, unacceptable effects on, or contamination of, the environment, including soil organisms; and their use has no unacceptable effect on the quality and safety of the final product”. In addition, the Codex guidelines on organic farming state that “any substances used in organic systems for soil fertilization … should comply with relevant national regulations”.
Nearly all commercial inorganic fertilizers meet the above-mentioned requirements, except the one on acceptable transformation processes. Therefore, only those inorganic fertilizers that comply with the processing requirement (a quite wide range of products, except for nitrogen fertilizers) are listed as authorized products by IFOAM and Codex Alimentarius. Unfortunately, restrictions on the use of certain inorganic fertilizers set by both organizations do not have scientific justification, and they should not be interpreted as the authorized fertilizer products being safer.
The list of Codex Alimentarius authorized products places additional requirements on some inorganic fertilizers, e.g. the chlorine content of potassium salts must be less than 60%, while sodium chloride has no restrictions. These additional requirements are not supported by any scientific evidence, nor are they included in the recommendations of the IFOAM list.
Need for uniform requirements for both organic and inorganic fertilizers
There are few requirements for organic fertilizers of animal or plant origin. In the Codex Alimentarius guidelines, the only restriction is that substances of animal origin (farmyard and poultry manure, slurry, urine) shall not come from management systems that are heavily reliant on veterinary and feed inputs and that human excrements shall not be applied to crops intended for human consumption. In the IFOAM basic standards, the only limitation applies to human excrements, which shall not be directly applied on edible parts of crops. These requirements are certainly too weak and ambiguous to ensure appropriate levels of food safety, with respect to the significant pathogen risk associated with some organic nutrient sources, especially if they are not composted or improperly composted.
Today, some products sold to organic farmers for use as soil amendments or organic fertilizers are not subject to the same standards for food and environmental safety as inorganic fertilizers. For instance, in its basic standards, IFOAM asserts that “mineral inputs should contain as few heavy metals as possible”. In fact, this requirement on heavy metals should apply equally to organic sources, which often contain much higher levels of heavy metals, per unit of nutrient applied, than inorganic fertilizers.
It is imperative that standards look at the important characteristics of the nutrient products, regardless of their origin, and that uniform safety regulations based on sound science be applied to all fertilizer sources used to supply nutrients for food production.
Based on sound science, IFA supports and promotes, in close collaboration with other stakeholders, integrated plant nutrition management strategies, which use both inorganic and organic nutrient sources in a timely, balanced and responsible manner according to soil supply capacity and crop requirements.
Information reserved for IFA members
What are message maps?
Message maps are tools for communicating information. They ensure that information has the maximum chance of being heard, understood and remembered.