The concept of sustainability, and more generally of sustainable agriculture, is based on the criterion of using natural resources at an intensity that allows for the regeneration of these resources. Sustainable use of resources should not, however, result in losses in productivity and quality. To achieve this, we tend to think in terms of resource use efficiency, ensuring that consumption is sustainable and aligned with the quality needs of the product in the production chains. Well-managed agro-forestry systems tend, in the long term, to ensure an adequate availability of resources that can mitigate disturbances that naturally occur and can compromise the yield and quality of food production.

The question is a bit vague and generic. In any case, the cultivation techniques applied to wheat, and particularly soil tillage, are classified based on the intensity and type of technique used. Generally, soil tillage aims to control spontaneous weeds that can compete with the main crop. Secondly, it allows for the burial of crop residues, manure, amendments, and nutrients. Moreover, tillage affects the soil compaction level and regulates water retention capacity. In addition to traditional tillage techniques (plowing, refining, etc.), there are also minimal tillage solutions or direct seeding that allow for minimal disturbance of the agricultural soil.

Direct seeding or no-till seeding can be carried out using appropriate seeders capable of overcoming greater soil compaction and allowing for regular and homogeneous seed distribution and emergence. There are different types of seeders based on size, hopper feeding capacity, distribution elements (mechanical, pneumatic), and the type of working element (anchor or hoe, disk, broadcast, etc.). The choice of using disk or anchor elements depends on soil conditions and existing crop residues that may interfere with seeding (stones, straw, plant residues). Generally, it is good practice to ensure good soil preparation, even with shredders, to break down any residues and ensure good penetration of the seeding element. Furthermore, different no-till seeders generally include a pressure load adjustment that must be regulated according to soil compaction. Inadequate adjustment can affect the quality of the seeding.

Applied biotechnologies include a wide range of applications in agricultural sciences, from the genetic manipulation of agricultural plants to the use of starters in the agro-food field. Plant growth-promoting bacteria (PGPB) are bacterial microorganisms capable of promoting the growth of agriculturally important plants. There are numerous microorganisms whose interaction efficacy with plants is highly complex and dependent on various often uncontrollable variables. Generally, the use of microorganisms that can survive well in the soil under certain conditions can be a winning factor.

Assuming reference is made to the production of durum wheat grain, it is an important food source in the Mediterranean diet and beyond. The durum wheat caryopsis is mainly composed of starch (50-80%), which provides adequate caloric needs in foods such as bread and pasta. The amylose/amylopectin ratio is genetically controlled and favors amylopectin, making it highly digestible. Additionally, wheat grain is a source of proteins (8-18%), mostly alcohol-soluble and technologically valuable as they are responsible for gluten formation. A significant fiber content is present mainly in the outer layers (bran), so only wholemeal flours are rich in it. About 1% consists of ashes, i.e., minerals available for nutrition, including trace elements such as iron and zinc.

Plant growth-promoting bacteria (PGPB) include microorganisms capable of promoting the development of agro-food plants. The most important genera include Bacillus, Pseudomonas, Azospirillum, Azotobacter, and Rhizobium. The biostimulation mechanisms are diverse and include atmospheric nitrogen fixation, organic matter degradation, siderophore activity, phosphorus and potassium solubilization, and indoleacetic activity. Some microorganisms can also play a biological control role to contain other pathogenic microorganisms.

Conservative agriculture is based on three pillars: minimal soil disturbance, management of surface layers with the enhancement of crop residues and the use of cover crops, and crop rotation. The latter is a very important requirement as it allows for reducing the pressure of biotic stresses (weeds, fungal diseases, etc.), making the system more stable and not solely dependent on agrochemicals. Crop residues also help increase organic matter and can act as a mulch to reduce evaporation losses during the hottest months.

The experimental activity was carried out through two field experiments over two consecutive agricultural years. Two different durum wheat varieties representative of the present varietal panorama and characterized by different productive and qualitative attitudes were used. Moreover, a direct seeding system was compared with a soil tillage system. Different fertilization types were also tested to promote sustainability and quality objectives. The trials were conducted on 18 m² plots each, in a split-plot experimental design with three replications. Weather data, growth, and development of the wheat crop in the different experimental plots were monitored. Among the main parameters considered, besides grain yield, were nitrogen use efficiency (also using an unfertilized check), grain quality (protein content, protein composition), and economic sustainability.

Direct seeding, among its various implications, increases soil water retention capacity, increasing specific weight and organic matter content. Therefore, it is particularly recommended in environments characterized by high evapotranspirative deficit that can severely affect yields. On average, as observed in experimental trials and widely indicated in scientific literature, soil tillage does not significantly impact cereal yields. Therefore, it is particularly recommended considering the fewer inputs needed for cultivation, subject to the recommendations of proper seedbed preparation and the use of machines suitable for such operations.

In reference to the experimental field trials, an economic analysis of the performance was also conducted. Generally, using a conservative agriculture approach and, in particular, no-till seeding significantly reduces costs as many of the classic and expensive soil tillage operations for seedbed preparation are no longer necessary. However, using a shredder to break down plant residues present can be recommended. Considering that no-till seeding treatments did not show lower yields than conventionally tilled soils, the gross saleable production obtained through no-till seeding was higher, even without considering potential community contributions. Additionally, optimized fertilization further increased environmental and economic sustainability.