Although input use in organic agriculture is strictly regulated, and significantly less contentious inputs are applied in organic than in conventional farming systems, copper, mineral oil, external nutrient input, anthelmintics, antibiotics and vitamins are still commonly used among organic farmers in the EU, partly due to the scarce availability of alternative products and the difficulty of implementing preventive strategies.

Many organically managed farms in Europe have low levels of soil phosphorus (P). Arable farms that rely strongly on biological nitrogen fixation (BNF) have been shown to have rather low outputs and a tendency to deplete soil P and potassium (K) compared with arable farms that have a lower reliance on BNF and higher external inputs. Therefore, research focusing on providing a balanced input of nitrogen (N), P, K and sulphur (S) from alternative sources is of interest to organically managed farms in Europe.

Controversy has long surrounded the question of nutritional differences between crops grown organically or using now-conventional methods, with studies dating back to the 1940s showing that farming methods can affect the nutrient density of crops. More recent studies have shown how reliance on tillage and synthetic nitrogen fertilizers influence soil life, and thereby soil health, in ways that can reduce mineral micronutrient uptake by and phytochemical production in crops.

Cover crops (CCs) are a promising and sustainable agronomic practice to ameliorate soil health and crop performances. However, the complex of relationships between CCs, the soil, and the plant nutritional status has been little investigated. In this article, for the first time, we critically review, under a holistic approach, the reciprocal relationships between CCs and the soil physical and hydraulic properties, microbial, and faunal communities, soil nutrient availability, and plant nutritional status in temperate climates.