This literature review explores the assessment of biochar quality and its impact on soil properties using diffuse reflectance spectroscopy. Biochar, a product of biomass pyrolysis, is recognized for its positive effects on soil fertility and carbon sequestration. This review emphasizes the need for systematic research on biochar stability and highlights the potential of diffuse reflectance spectroscopy for analyzing soil–biochar interactions. Biochar acts as a soil conditioner, improving physical, chemical, and biological properties and enhancing soil fertility and crop yield. Furthermore, it aids in mitigating climate change by sequestering carbon dioxide. However, the long-term behavior of biochar and its interactions with various factors require further field research for optimal utilization, as the aging process of biochar in soil is complex, involving physical, chemical, and biological interactions that influence its impact on the agroecosystem. This review also emphasizes the importance of studying the interaction between biochar and soil microbes, as it plays a crucial role in enhancing soil fertility and plant resistance to pathogens. However, research on this interaction is limited. VIS-NIR spectroscopy is a valuable tool for monitoring biochar application to soil. Nevertheless, controversial results highlight the intricate interactions between biochar, soil, and environmental conditions.

Two successive lettuce crops were grown in spring 2005 in a completely closed hydroponic system. The ratio of ammonium to total nitrogen ( N _r ) in the fresh nutrient solution (FNS) introduced into the closed system to compensate for plant uptake was 0, 0.1, 0.2 and 0.3 on a molar basis. In all N _r treatments, the concentrations of total N, K, Ca, Mg, P, and micronutrients in the FNS were identical, but that of SO ₄ ^2– increased as N _r increased, to compensate electrochemically for the enhanced NH ₄ ⁺ and decreased NO ₃ ^– supply. The highest fresh and dry weights per plant were attained with the highest ammonium supply ( N _r = 0.3) but, even when no NH ₄ ⁺ was included in the FNS as an N source, the plants were healthy without apparent nutritional disorders. The ammonium concentration in the drainage solution dropped to nearly zero in all treatments some days after the initiation of recycling, which implies a preferential uptake of NH ₄ -N over NO ₃ -N. The root zone pH, as indicated by the values measured in the drainage solution, decreased slightly as N _r increased, and ranged from 6.5 to 8.0 in all treatments. The leaf K, Ca, Mg, and Fe concentrations were not influenced, whereas those of P, Mn, Zn, and Cu were enhanced by the increasing NH ₄ ⁺ supply. The increased ammonium supply did not enhance the utilization of N in plant metabolism, although it reduced the nitrate concentration of the internal leaves in the early spring experiment. The leaf micronutrient concentrations were clearly more than critical levels even when NO ₃ ^– was the sole N source for lettuce, whereas the P concentration approached the lowest critical level when N _r was 0 or 0.1. The stimulation of lettuce growth as N _r was increased to 0.3 may be a consequence of enhanced P uptake resulting from better control of pH in the root zone.

Great advancements in technologies such as big data analytics, robots, remote sensing, the Internet of Things, decision support systems and artificial intelligence have transformed the agricultural sector. In the greenhouse sector, these technologies help farmers increase their profits and crop yields while minimizing the production costs, produce in a more environmentally friendly way and mitigate the risks caused by climate change. In greenhouse farming, especially in the Mediterranean region, a lack of knowledge and qualified personnel able to uptake new knowledge, the small size of farms, etc., make it difficult to implement new technologies. Although it is necessary to demonstrate the advantages of innovations related to sustainable agriculture, there is a little opportunity for specific training on greenhouse production in cutting-edge technologies. To gain insight into this problem, questionnaires for greenhouse farmers and intermediaries were developed in multiple choice format and filled in by the stakeholders. A statistical analysis was performed, and the results are presented in graphical form. In most cases, the findings confirmed that producers who run small farms, in most cases, have a lack of knowledge, especially on how to manage climate control systems or fertigation systems. The majority of farmers were elderly with a low level of education, which makes it difficult to be aware of the training issues, due to distrust and a lack of innovation culture. Therefore, their strategy was usually survival with cost control. However, young graduates have been recently returning to agriculture, and they are open to training activities and innovation. The most desirable training offer should be related to sustainable agriculture and precision agriculture technologies.

Olive cultivation is expanding rapidly in the northwestern part of Greece, under both rainfed and irrigated practices. Irrigation can result in larger yields and economic returns, but trade-offs in the water–energy–pollution nexus remain a controversial and challenging issue. This study presents an environmental Life Cycle Assessment (LCA) of Greek olive orchard systems in the plain of Arta (Epirus), comparing rainfed (baseline), Decision Support System (DSS)-based (smart) irrigation practices and farmer experience-based (conventional) irrigation practices. The contributions in this paper are, first, to provide a first quantitative indication of the environmental performance of Greek olive growing systems under different management strategies, and second, to detail the advantages that can be achieved using smart irrigation in olive cultivation in the Greek and Mediterranean contexts. Eighteen midpoints (e.g., climate change, water scarcity, acidification, freshwater eutrophication, etc.), two endpoints (damages on human health and ecosystem quality), and a single score (overall environmental impact) were quantified using the IMPACT World+ life cycle impact assessment method. The LCA model was set up using the OpenLCA software v1.10.3. The functional units were 1 ton of product (mass-based) and 1 ha of cultivated area (area-based) on a cradle-to-farm gate perspective. Irrigated systems had the lowest impacts per mass unit due to higher yields, but showed the highest impacts per cultivated area. The DSS-based irrigation management could reduce water and energy use by 42.1% compared to conventional practices. This is translated into a reduction of 5.3% per 1 ton and 10.4% per 1 ha of the total environmental impact. A sensitivity analysis of impact assessment models demonstrated that the benefits could be up to 18% for 1 ton of product or 22.6% for 1 ha of cultivated land. These results outline that DSS-based irrigation is a promising option to support less resource-intensive and sustainable intensification of irrigated agriculture systems in the plain of Arta.