Giuseppe BADAGLIACCA

Lentil (Lens culinaris Medik.) is widely known among grain legumes for its high nutritional quality, playing an important role in enhancing Mediterranean farming systems as a sustainable crop. Field experiments comparing 121 lentil accessions (microsperma and macrosperma types from different countries) were conducted in a semi-arid environment of south Italy over two growing seasons (2016/2017 and 2017/2018). Their agronomic performance was determined, focusing on phenological, morphological, productive, and qualitative variability. Changes in rainfall and temperatures affected the agronomic traits, especially yield components. In both years, the average grain yield (GY) (2.31 and 2.22 t ha−1, respectively) was above the threshold of 2 t ha−1. Consistent yield exceeding the field average in both growing seasons revealed the superiority of accessions from Egypt, Cyprus, Algeria, Nepal, and Tunisia. Moreover, microsperma yielded more (+0.31 and +0.41 t ha−1 in the first and second year, respectively) than macrosperma accessions. Flowering (DASF—days after sowing to flowering) and thousand seed weight (TSW) appeared to be the most important traits related to grain yield. Flowering earliness seems to act as a mechanism for overcoming abiotic stresses. The analysis of yield components revealed a different productive determinism within the two subspecies. As also highlighted by the Principal Component Analysis, microsperma accessions presented on average a significantly higher number of pods per plant (PP) and seeds per pod (SP), despite the considerable variability among countries of origin. The results showed phenological and morphological variability among genotypes, which should be taken into account in view of future selection programs focused on obtaining lentil ideotypes suitable for the Mediterranean environment.

In Mediterranean countries characterized by increasingly extended hot and dry periods, olive trees are often conventionally practiced in low fertility and rainfed soils. This study investigated over a 15-month period how conventional tillage, combined with or without incorporated solid digestate, and no tillage affected selected soil properties, photosynthetic activity and productivity of mature olive trees growing in highly clayey acid soil with an unbalanced nutrient content and Mn excess. Neither in soil nor in drupes were Mn, Fe, Cu and Al contents affected by the managements. However, in soil, exchangeable Mn that was always larger than 200 mg kg−1 threshold and unbalanced Ca, Mg, and K contents were evidenced in all treatments. Non-tilled soil showed the highest (p < 0.05) stomatal conductance and photosynthetic rate, and the highest (p < 0.05) fruits and oil yields. Instead, conventional tillage negatively (p < 0.05) affected plant physiology and productivity, likely due to the tilled increase in aeration, enhancing soil water loss and organic C mineralization. Conversely, digestate addition increased TOC, TN and EC. Stomatal conductance, the photosynthetic rate and plant yield significantly recovered (albeit not to no-tillage values) in tillage combined with incorporated digestate, suggesting that digestate-derived organic matter created soil conditions less constraining to plant growth and productivity than the conventional tillage did. Dealing with soil properties and climatic conditions is the key for adopting the best management practice for preserving plant productivity and soil fertility.

Agriculture is facing several challenges related to its sustainability. In this regard, the need to reduce its environmental impact related to the use of synthetic inputs and its potential role in mitigating global warming and climate change call for a review of crop management. In this context, and in the framework of achieving sustainable development goals, the use of organic fertilizers and bio-waste represents a valuable contribution to the agricultural transition towards a bioeconomy model by reducing the negative impacts of waste disposal. Farmyard manure, composts, digestate from agrifood processes, and biochar are, among organic fertilizers, commonly used to manage soils and support crop growth. These fertilizers can provide essential nutrients, improve structure, and enhance microbial activity, thus increasing soil fertility and agriculture sustainability. While organic fertilizers offer the benefits of soil fertility and plant nutrition, their impact on greenhouse gas (GHG) emissions is complex and varies depending on factors such as fertilizer type, soil conditions, and management practices. Although organic fertilizers may initially increase GHG emissions, they often lead to carbon sequestration in soils highlighting a negative C balance. Additionally, organic fertilizers promote a reduction in fossil fuel consumption used for synthetic fertilizer production, further contributing to GHG emissions’ reduction. Therefore, while organic fertilizers pose challenges in managing GHG emissions, their various benefits warrant careful consideration and strategic implementation in agricultural systems.