A study conducted in India observed that by replacing chemical fertilisers with organic ones, vegetables regain the nutrients lost over decades of intensive farming. A study conducted in India observed that by replacing chemical fertilisers with organic ones, vegetables regain the nutrients lost over decades of intensive farming.
Vegetables are essential components of the diet, as they are a source of vitamins, minerals, fibre, enzymes and antioxidants that are fundamental to the health and wellbeing of the body. In recent decades, however, intensive farming practices based on the use of nitrogen-based chemical fertilisers have reduced the fertility and biodiversity of the soil, consequently diminishing the nutritional, nutraceutical and organoleptic quality (the flavour) of many vegetables.
According to a study conducted in India, published in Academia Nutrition and Dietetics, many high-yield commercial vegetable varieties have experienced a decline of 25–50 per cent compared to their original nutritional density in essential minerals such as sodium (-52 per cent), iron (-50 per cent), copper (-49 per cent) and magnesium (-10 per cent), while at the same time a significant increase in pesticide residue levels has been recorded.
Starting from the awareness of the need to restore the properties of vegetables in order to address global food security and the micronutrient deficiencies suffered by two billion people worldwide, the researchers conducted field experiments between 2019 and 2024, testing six different treatments on crops such as potatoes, cabbages, onions and peas, radishes, green beans and black-eyed peas. The treatments ranged from the exclusive use of chemical fertilisers to combinations with organic sources (manure, vermicompost) integrated with naturally occurring microorganisms that promote plant growth (Pgpm), through to the exclusive use of natural substances.
The results showed that the complete replacement of chemical fertilisers with organic sources in the presence of Pgpm significantly improves the physicochemical properties of the soil and nutrient availability, thereby enhancing the nutritional, nutraceutical and organoleptic quality of vegetable crops — in other words, their beneficial properties and taste. Among the most significant improvements recorded are increases in levels of calcium (23.84 per cent), phosphorus (3.63 per cent), iron (31.70 per cent), zinc (48.48 per cent), magnesium (15.06 per cent), nitrogen (7.76 per cent) and potassium (11.09 per cent) compared to 100 per cent chemical fertilisation, along with a higher antioxidant content.
Treatment with organic sources had a beneficial effect in restoring the microbial populations of the soil, in increasing organic carbon content and in improving the availability of mineral nutrients in the root zone. Careful soil management through sustainable farming practices represents a form of agriculture that is mindful of both the environment and nutrition — a fundamental contribution to global food security and health.