What’s in store for fertilization?

The cultural context in which farmers operate today is strongly conditioned by the consequences and harmful effects of climate change, which include the alteration of nutrient cycles and the existing balances between the different forms of organic matter contained in the soil. These alterations, as explained below, are reflected in a loss of organic matter from cultivated land and in an increase in the rate of carbon dioxide released into the atmosphere, which in turn fuels the greenhouse effect.

What importance and what role does proper fertilization management play in today’s agriculture?

The progressive loss of organic matter from cultivated soils, especially those located in countries bordering the Mediterranean basin, is a well-known topic.

This is better specified in a document on the subject produced by ISPRA (Higher Institute for Environmental Protection and Research), “… the situation is not reassuring and is aligned with European estimates: about 80% of Italian soils have an organic carbon content (to transform the organic carbon content measured in the corresponding content into organic substance, the following equation is used: SO = CO x 1.724, editor’s note) less than 2%, of which a large percentage has organic carbon values of less than 1%. All this translates into a large percentage of soils with lower organic matter values or slightly higher than 2%. The estimate is based on the analyses carried out for the creation of the Ecopedological Map of Italy integrated with data from the European Soil Database”.

These are still acceptable levels of soil organic matter, at least for many crops, but they are in a worrying decline, mainly due to climate change and the repeated use of intensive agricultural practices that do not respect the health of cultivated land.

To better understand the above, just ponder that the organic matter content of forest soils (where the action of “disturbance” due to agricultural practices does not exist) is equal to about 10%.

Climate change and the rise in temperatures (average, minimum and maximum) that it brings, accelerate the mineralization of the stable fraction of the organic substance (humus), releasing carbon dioxide into the atmosphere, but also other gases potentially capable of contributing to the greenhouse effect. This phenomenon, as it is easy to guess, fuels climate change and therefore goes against the desired “mitigation” or the adoption of production processes (including agricultural ones) and more generally of virtuous behaviour capable of reducing emissions. There are also examples of technologies for removing CO² from industrial exhaust fumes or directly from the atmosphere, but we are still far from the possibility of application on a large scale.

The reduction of organic matter in cultivated soils, as we were able to emphasize several times in our studies, involves the loss of structure, the creation of asphyxiated conditions (which create imbalances in the telluric microbiota) and the reduction of the capacity to incorporate water and therefore to accumulate water reserves in the deeper layers. The reduced infiltration of rainwater and irrigation water facilitates runoff and erosion, thus causing the loss of the most fertile surface layers of the soil. Together these phenomena lead to desertification and loss of fertility. In arid soils, destructured and poor in organic matter and useful microorganisms, the nutritional elements deriving from the mineralization of the organic substance, in addition to those eventually distributed with mineral fertilization, determine a concentration of salts in the surface layers. Salinization is another extremely worrying phenomenon, closely interconnected with those described above and co-responsible for the loss of fertile land.

Loss of stable organic matter, destructuring, erosion and salinization can be counteracted through the application of soil-friendly cultivation practices. These involve, for example:

• the reduction of mechanical processing, which must instead be carried out while ensuring not to upset the horizons of the soil and in any case with soil il “optimal temperature and condition”;
• where possible, the exploitation of grassing and/or planting of cover crops and/or green manure crops;
• the reduction of the weight of work sites and the number of entries in the field;
• the use of the latest generation tires;
• a careful choice of techniques for managing weeds, in order to limit to a minimum the alteration of the balance within the microbial populations present in the soil;
• the rational management of fertilization.

How do you manage the practice of fertilization to make it sustainable: environmentally (reducing impact), agronomically (maintenance/regeneration of fertility) and economically (maintaining yields and product quality, reducing waste from useless and inefficient inputs)?

This is the exact benefit of using organic and/or organo-mineral products. Providing stable and good quality organic matter to the soil means reducing mineralization processes and CO₂ emissions into the atmosphere, while limiting the loss of nutrients due to leaching, evaporation and immobilization, as well as the risks of desertification. Therefore, organic and/or organomineral fertilization provides organic carbon exactly where it is needed.

Given that the farmer cannot afford to reduce the yields of his crops below certain levels, under penalty of the economic unsustainability of his activity, agriculture today cannot ignore the use of fertilizers. Maintaining productivity at optimal levels by reducing fertilizer doses and, above all, increasing their efficiency, in order to reduce element losses, environmental impact and the depletion of soils and subsoils, is possible. The way in which the nutrients contained in organic and organo-mineral fertilizers become bioavailable for absorption by plant roots, makes it possible to optimize doses without compromising production and at the same time improving soil structure, with a view to regenerative agriculture.