Medicinal and Aromatic Plants Diversity in Greece and Their Future Prospects: A Review

Maize is the predominant raw material (together with sugar cane) for the production of bioethanol, the most common and widespread biofuel, and at the same time the predominant raw material for biogas production, with the highest yields in Europe. The advantage of maize biomass over other energy plants is the fact that biomass occurs after harvesting the seed and does not require the use of a different area for its development. The main drawback of the use of maize biomass is the negative effects of removing crop residues on fertility and the physical properties of the soil. Bioethanol’s share of global biofuel production is over 94%, as many countries are replacing a portion of their fossil fuels with biofuels, according to international regulations. The choice of crops used as feedstock for the production of bioethanol is strongly associated with local climatic factors. About 60% of world bioethanol production is made with cane raw material in the Central and South American countries, with Brazil leading, while the remaining 40% from other crops with North America producing bioethanol almost exclusively from maize, and the EU uses as raw material raw starch (cereals and maize) as well as crops such as sugar beet and sweet sorghum.

The urban zone around the city of Volos, a Greek city with a historically industrialized profile, faces threats arising from Potential Toxic Element (PTE) contamination. The scope of this study is to determine the contamination levels of 10 PTEs in three urban areas which are located near the industrial zone in the city of Volos. For this purpose, a total of 30 soil samples from parks, playgrounds and roadsides were collected from the Agios Georgios, Velestino and Rizomilos areas (Magnesia, Central Greece). The sampling was conducted in June 2022 and the concentrations of chromium (Cr), nickel (Ni), copper (Cu), arsenic (As), cadmium (Cd), lead (Pb), iron (Fe), manganese (Mn), cobalt (Co) and zinc (Zn) were measured through inductively coupled plasma mass spectrometry (ICP-MS). The Contamination Factor (CF), Pollution Load Index (PLI) and Geo-accumulation Index (Igeo) revealed moderate pollution in most cases, whereas in some sites the contamination was significant for Ni or for As. Principal Component Analysis showed concomitant changes for some PTEs in Component 1 and for others in Component 2, explaining approximately 67% of the variation. K-means Cluster Analysis showed two distinct groups of PTE-impacted sites within these urban areas. It can be postulated that industrial activities may have a carry-over effect on the soil in residential areas. Frequent monitoring of areas deemed as “contaminated” and time-series data are needed to examine in depth the soil pollution in cities and its possible shifts in relation to the changes in industrialization status in the extended urban areas.

The long-term positive effects of cropping systems involving rotation with cover crops on soil properties and the environment are well recognized. The present work concerns a 3-year field experiment focusing on two cropping systems including two energy crops [maize (Zea mays L.) and sunflower (Helianthus annuus L.)] cultivated May–September on an infertile sandy soil, and Pisum sativum cultivated as cover crop after the harvest of the energy crop. Soil samples from two soil layers, 0–20 cm and 20–40 cm deep, were collected at the beginning and end of the experiments; they were analyzed for soil physical and chemical properties such as soil moisture properties, total nitrogen (N), phosphorus (P), potassium (K), pH, organic matter, and organic carbon (C). The results demonstrated the effect of pisum intercropping on the performance of the subsequent energy crop. These results are particularly important for the cultivation of less fertile soils such as sandy soils, which can be put in use for the production of energy crops such as maize and sunflower, which are characterized by high nutrient—particularly N—demand.

Soil erosion is among the biggest problems in the agricultural sector that can affect ecosystems and human societies. A field of 5° slope was selected to study the runoff, soil and nutrient loss as well as crop productivity in different treatments—conventional tillage (CT) vs. no-tillage (NT), plant vs. no plant cover, contour cultivation (CC) vs. perpendicular to the contour cultivation, (PC) under natural rainfall. The experiment was conducted in central Greece in two cultivation periods. In autumn, the field was cultivated with intercropping Triticosecale and Pisum sativum and in spring with sunflower. The total rainfall was 141.4 mm in the 1st year and 311 mm in the 2nd. We found that runoff in the treatment of no tillage with contour cultivation was 85% lower in both years compared to the no tillage-no plant control. Therefore, the contour cultivation-no tillage treatment had a positive effect by decreasing phosphorus and potassium loss from soil: indeed, there was a decrease in P and K by 55% and 62%, respectively, in the NT compared to the CC treatments. We conclude that the NT-CC treatment with plant cover was the most effective in reducing water runoff and soil nutrient loss and increasing yield.