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Potato (Solanum tuberosum L.) is a widely consumed and essential food crop globally, making it an ideal food matrix for biofortification. Agronomic biofortification is one of the strategies used to enhance Ca content in edible parts of crops, considering the adverse health issues associated with Ca deficiency. This study aims to investigate the impact of Ca agronomic biofortification through four foliar applications after the beginning of tuberization on the yield of tubers of Solanum tuberosum L. (Picasso variety) produced in Lourinhã (Portugal) in 2018, focusing on the application of calcium chloride or, alternatively, calcium nitrate at different concentrations (calcium chloride—1, 3, 6 and 12 kg/ha or calcium nitrate—0.5, 1, 2 and 4 kg/ha). Control plants and plants subjected to the different Ca treatments were placed in plots of 20 × 24 m; the treatments were carried out in quadruplicate (compass 60–80 cm). As such, the Ca content in tubers was quantified by atomic absorption spectrophotometry in the different treatments. The Ca biofortification index with calcium chloride or calcium nitrate ranged between 5 and 40%, with the treatment with 6 kg/ha CaCl2 being the one which presented the highest Ca content in tubers at harvest and 1 kg/ha CaCl2 being the treatment with the lowest Ca biofortification index. However, 6 kg/ha CaCl2, despite presenting the highest Ca content, was not the treatment that presented the highest yield. Indeed, all the calcium nitrate treatments demonstrated a substantial increase in tubers yield, which varied between 2.3 (4 kg/ha Ca(NO3)2) and 24.3% (2 kg/ha Ca(NO3)2). Statistical analysis was carried out in all the analyses using one-way ANOVA to assess differences among treatments in Solanum tuberosum L. (Picasso variety), followed by Tukey’s analysis for mean comparison, with a 95% confidence level. Furthermore, these findings emphasize the potential of Ca biofortification, especially calcium nitrate treatments, in enhancing the yield of Solanum tuberosum L. tubers.

Remote sensing technology (namely UAVs) has been used to monitor potato crops. As such, this study aims to analyze the relationship between the NDVI model and yield productivity in Solanum tuberosum L. plants from the Agria variety, submitted to a Ca biofortification process with two different concentrations (12 and 24 kg/ha) of CaCl2 or Ca-EDTA. The NDVI values were collected six days after the six foliar applications and analyzed alongside the Ca content in the potato tubers (at harvest) and the total yield. The results highlight the fact that 24 kg/ha of CaCl2 presented the lowest NDVI value, yet these plants did not show the lowest yield. Moreover, that same treatment presented the highest Ca biofortification index in tubers. Also, it seems that the NDVI can be used in decision making to improve crop management strategies, considering that it is an indicator for detecting plant growth or vigor; however, in this research, it is not sufficient for yield prediction.

Rice (Oryza sativa L.) is one of the most economically and socially important cereals in the world. Several strategies such as biofortification have been developed in a way eco-friendly and sustainable to enhance crop productivity. This study implemented an agronomic itinerary in Ariete and Ceres rice varieties in experimental fields using the foliar application of selenium (Se) to increase rice nutritional value. At strategic phases of the plant’s development (at the end of booting, anthesis, and at the milky grain stage), they were sprayed with sodium selenate (Na2SeO4) and sodium selenite (Na2SeO3). In the first foliar application plants were sprayed with 500 g Se·ha−1 and in the remaining two foliar applications were sprayed with 300 g Se·ha−1. The effects of Se in the level of micro and macronutrients in brown grains, the localization of Se in these grains, and the subsequent quality parameters such as colorimetric characteristics and total protein were considered. After grain harvesting, the application of selenite showed the highest enrichment in all grain with levels reaching 17.06 µg g−1 Se and 14.28 µg g−1 Se in Ariete and Ceres varieties, respectively. In the Ceres and Ariete varieties, biofortification significantly affected the K and P contents. Regarding Ca, a clear trend prevailed suggesting that Se antagonizes the uptake of it, while for the remaining elements in general (except Mn) no significant differences were noted. Protein content increased with selenite treatment in the Ariete variety but not in Ceres. Therefore, it was possible to conclude, without compromising quality, that there was an increase in the nutritional content of Se in brown rice grain.

Rice (Oryza sativa L.) is considered one of the most consumed cereals worldwide. In fact, for most countries, it is considered a staple food crop. In this context, in Portugal, Ariete and Ceres are well known as varieties that produce grains with a high quality, yet little is known about their nutrient accumulation. In this context, this study aims to characterize and compare both varieties produced in the central region of Portugal (Salvaterra de Magos-Ribatejo). Whole and white rice grains, as well as their respective flours, were analyzed in order to quantify the mineral content of macro- and microelements (Mo, Ca, K, P and S). Molybdenum (Mo) content varied significantly between 4.7–11.2 mg·kg−1 in the whole flour of Ceres and Ariete, respectively, while P content was only detected in the flour of the Ariete variety. Regarding both varieties, concerning the other elements, there were no significant differences in their content. Moreover, the total ash content in the refined flour showed significant differences in both varieties. Quality parameters such as the density of the grains and colorimetric indexes (L, a* and b*) in brown and white grain were also considered, and it was found that density values varied between 1301–1651 kg/m3 (in the Ariete variety) and 1492–1573 kg/m3 (in the Ceres variety). It was concluded that, in spite of the differences found in both varieties, minerals contents, combined with the quality parameters, showed common characteristics required for high industrial and gastronomic potential.

Soil is considered a highly complex ecosystem, providing food and maintaining crop and animal productivities. Soil variability can affect plant production. Accordingly, this study aimed to compare soil chemical characteristics from two different locations in the same region of western Portugal (Lourinhã), intended for potato production. Soil was collected and analyzed for soil chemical properties (pH, electric conductivity, organic matter, and mineral element content). Through a principal components analysis (PCA), it was possible to identify that the interrelations among the mineral elements were explained in the projections of components one and two for both fields. Regarding Field A, Ca, K, Fe, P, S, Mg, As, Pb, and Zn are more correlated with each other than the other mineral element (Cd). On the other hand, in Field B, all the mineral elements correlate differently compared to Field A (except Cd), and show that K, As, Mg, Ca, Zn, Fe, and Pb are the most correlated with each other. Additionally, Fe and S are more correlated in Field A; however, in Field B, Fe and Zn are the ones that are more correlated with each other. Additionally, although both soils have the same pH (slightly basic soil—ideal for agriculture), they show a significantly different content of organic matter and conductivity, where Field B presents higher contents of both parameters. The obtained data are discussed, concluding that the soils, despite being geographically close, have different relationships between elements and different contents of organic matter and electrical conductivity, which may lead to differences in potato production.

Appropriate soil conditions are important for the success of culturing tomatoes. In fact, there are mineral elements that are essential for the good and healthy development of tomatoes, namely, nitrogen, phosphorus, potassium, calcium, magnesium, sulfur, iron, and zinc. Additionally, organic matter and pH play important parts in the process. In this context, this study aimed to characterize a soil destined to produce an industrial tomato variety in South Portugal. As such, mineral elements content, pH, electrical conductivity, humidity, organic matter, and color (without humidity and without humidity and organic matter) were analyzed in 16 soil samples before any type of soil preparation was carried out. Through principal components analysis (PCA), it was possible to observe that electrical conductivity and humidity are more correlated with each other than pH and organic matter. However, the pH of soil varied between 6.9 (minimum) and 7.3 (maximum): in accordance with the ideal range values for tomato production. Additionally, regarding quantification of mineral elements, Fe showed a higher content, followed by K, Ca, P, Mg, S, Zn, and As. However, regarding the color of the soil without humidity and without humidity and organic matter, there were significant differences between CieLab parameters (L, Chroma, and Hue). Nevertheless, soil conditions of the field presented good requirements for tomato production, despite the higher levels of Fe in the soil and the presence of As.

Remote sensed data already have an important role in crop management. In fact, NDVI (normalized difference vegetation index) has been use for staple crop management and monitorization since the 1980s, namely, in rice, wheat and maize. Accordingly, this study aimed to monitor, through precision agriculture, the development of a highly produced and consumed rice genotype in Portugal (Ariete variety), submitted to a selenium biofortification workflow. Rice biofortification was promoted during the production cycle, and assessed after two foliar applications with selenium (sprayed with 50 and 100 g Se·ha−1 of sodium selenite). In this context, NDVI showed a high and identical value between control and biofortified plants, which indicated that the culture displayed a higher vigor and was in a healthy state of development despite foliar applications. Analyzes were further carried out for monitor the mobilization of photoassimilates, showing that plants did not demonstrate any negative impact on net photosynthesis and there was even a slight rise in the treatments. Additionally, to characterize the soil of the paddy rice field, some parameters were also analyzed, namely, organic matter, humidity, pH and electrical conductivity, being found that the parameters ranged between from 1.085–1.575%, 12.05–17.45%, 5.70–6.20, respectively, whereas the average conductivity was 223.4 µS cm−1. Concerning to soil color, and considering the parameters L, a* and b* of the CIELab scale, significantly higher values in samples without humidity and without humidity and organic matter were found. In spite of the differences found, it is concluded that biofortification process did not affect any physiological parameters (net photosynthesis–Pn, stomatal conductance to water vapor—gs, transpiration rates—E and instantaneous water use efficiency—iWUE) in rice plants.

The aim of this study is to evaluate the elemental composition of fifteen algae-based supplements commonly sold in the Portuguese market, by energy dispersive X-ray fluorescence. Despite the fact that the majority of Kelp samples were a good source of iodine, the levels observed might well contribute to an excess in the human body, which can cause dysfunction of the thyroid gland. Furthermore, the presence of lead in Sea spaghetti, Arame, Hijiki and Wakame caused a considerable risk to public health vis a vis possible ingestion of a high daily dose. Regarding arsenic, great variability was observed in all the samples with concentrations equal to or above 60 μg/g in the case of Arame, KelpJ and Hijiki. Although algae mainly accumulate organic arsenic, some also contain high levels of its inorganic form, as is commonly pointed out for Hijiki. Thus, regular ingestion of these supplements must also take into account the mentioned facts. There is no doubt that these supplements are also good sources of other nutrients, but the lack of accurate regulations and control should alert consumers to avoid indiscriminate use of these types of products.

The contamination of abandoned mining areas is a problem worldwide that needs urgent attention. Phytoremediation emerges as a successful method to extract different contaminants from the soil. In this context, Eucalyptus globulus plants growing in soils artificial contaminated with arsenic (As) were used to access its phytoremediation capabilities. The effects of As on photosynthetic performance were monitored through different physiological parameters, whereas the uptake and translocation of As and the putative effects on calcium, iron, potassium, and zinc levels on plants were evaluated by X-ray fluorescence analysis. Root system is the major accumulator organ, while the translocation to the above-ground organs is poor. In the end of the experiment, the root biomass of plants treated with 200 μg As mL−1 is 27% and 49.7% lower than equivalent biomass from plants treated with 100 μg As mL−1 and control plants, respectively. Each plant can accumulate 8.19 and 8.91 mg As after a 6-month period, when submitted to 100 As and 200 As, respectively. It seems to exist an antagonistic effect of As on Zn root uptake by E. globulus. In general, the tested concentrations do not influence negatively plant metabolism, indicating that this species is suitable for plantation in contaminated areas.

An agronomic itinerary for Se biofortification of two rice cultivars (Ariete and Ceres) through foliar fertilization with sodium selenate and sodium selenite with different concentrations (25, 50, 75 and 100 g Se.ha−1), was implemented in experimental fields. The selenium toxicity threshold was not exceeded, as shown by the eco-physiological data obtained through leaf gas exchanges. The highest Se enrichment in paddy grains was obtained with selenite for both cultivars, especially at the highest doses, i.e., 75 and 100 g Se.ha−1, with approximately a 5.0-fold increase compared with control values. In paddy grains, Zn was the most affected element by the treatments with Se with decreases up to 54%. When comparing the losses between rough and polished grains regardless of the cultivars, Se species and concentrations, it was observed that only Cu, Mg and Zn exhibited losses 70%. The loss of Se is more pronounced in Ceres cultivar than in Ariete but rarely exceeds 50%. The analysis by µ-EDXRF showed that, in Ariete cultivar, Se is mostly homogeneously distributed in the grain regardless of any treatments, while in Ceres cultivar, the Se distribution seems to favor accumulation in the periphery, perhaps in the bran.

This study aimed to assess the efficiency of Ca enrichment in tubers of three genotypes of Solanum tuberosum L., through foliar spraying with CaCl2 and Ca(NO3)2 solutions. In this context, soil heterogeneity of three potato-growing fields, as well as the implications of Ca accumulation among tissues and some quality parameters were assessed. Three potato varieties (Agria, Picasso and Rossi) were grown in three production fields and during the life cycle, four pulverizations with calcium chloride (3 and 6 kg ha−1) or calcium nitrate (0.5, 2 and 4 kg ha−1) were applied. For screening the potential phytotoxicity, using Agria as a test system, the potential synthesis of photoassimilates was determined, and it was found that after the 3rd Ca application, leaf gas exchanges were moderately (net photosynthesis), to strongly (stomatal conductance) affected, although without impact on Ca accumulation in tubers. At harvest, the average Ca biofortification index varied between 5–40%, 40–35% and 4.3–13% in Agria, Picasso and Rossi, respectively. Moreover, the equatorial region of the tubers in general showed that Ca accumulation prevailed in the epidermis and, in some cases, in inner areas of the potato tubers. Biofortified tubers with Ca also showed some significant changes in total soluble solids and colorimetric parameters. It is concluded that Ca enrichment of potato tubers through foliar spraying complemented the xylem mass flow of Ca from roots, through phloem redistribution. Both fertilizers showed similar efficiency, but Rossi revealed a lower index of Ca accumulation, eventually due to different metabolic characteristics. Although affected by Ca enrichment, potato tubers maintained a high quality for industrial processing.