More than ever, traditional agricultural practices need a shift towards more resilient, sustainable, modern and adaptable practices that benefit the health of the planet and people. Today's consumers ...are constantly on the lookout for novel, highly nutritious foods that have a positive impact on their overall health and well-being. Nettle (Urtica dioica L.) is gaining recognition not only as a popular medicinal plant, but also as a desirable green leafy vegetable rich in phytonutrients. As it is difficult and even expensive to control the quality standards of wild-collected plants, the implementation of sustainable cultivation methods, especially hydroponics, with effective greenhouse management could be a possible solution to obtain a standardized product with high nutritional value. Therefore, the aim of this study was to investigate the effects of four nutrient solutions differing in the content of macro- and micronutrients (especially nitrogen, potassium, calcium, magnesium and iron) and two consecutive cuts on the number of leaves, yield, nitrate and mineral content and the content of specialized metabolites of stinging nettle from a floating hydroponic system.
Nettle plants were cultivated in a hydroponic system using the floating hydroponics technique. The two-factorial experiment was performed with nutrient solution and consecutive cuts as factors.
The highest yield (2.49 kg/m2) was achieved after the 1st cut with plants cultivated in the nutrient solution with higher nutrient concentration. All tested nutrient solutions resulted in high levels of minerals and bioactive compounds in the plant material (ascorbic acid content of 102.30 mg/100 g fw and total phenolics content of 465.92 mg GAE/100 g fw), confirming floating hydroponics as a sustainable approach for cultivating nettle with enhanced nutritional value and antioxidant potential.
It is important to highlight that the nutrient solution with the lowest nutrient composition yielded the highest concentrations of calcium (5.54%) and iron (180.67 mg/kg dw). Furthermore, it exhibited elevated levels of specific phenolic compounds, including caffeoylmaleic acid, ellagic acid, ferulic acid, naringin, and rutin trihydrate. Notably, this solution demonstrated the lowest nitrate content (4225.33 mg/kg fw) in the plant material. Therefore, it can be recommended as a preferable formulation for hydroponic nettle cultivation.
As food production faces major challenges, modern agricultural practices are increasingly focused on conserving resources, reducing negative environmental impacts and sustainably producing food with ...a high content of health-promoting phytochemicals. During production, many factors can affect the quality and chemical composition of a final food product. Proper selection of cultivating conditions, especially a balanced nutrition, can significantly increase nutritional value and result in foods with strong biological and functional properties. Stinging nettle is a rich source of minerals, vitamins, pigments, phenols and other bioactive compounds and can be consumed as a green leafy vegetable with beneficial effects on human health. Therefore, the aim of this study is to determine the nutritional quality and antioxidant capacity of stinging nettle leaves under the influence of different nutrient solution (NS) treatments and three harvest cycles.
The experiment was conducted in a floating hydroponic system in which treatments with different nutrient solutions were applied and three harvest cycles were carried out. After each harvest, the following treatments were applied: treatment 1 - depletion of nutrient solution by adding water, treatment 2 - supplementation of nutrient solution by adding initial nutrient solution and treatment 3 - correction of nutrient solution by adding nutrients. Among the bioactive compounds, minerals, ascorbic acid, phenols and photosynthetic pigments content, as well as antioxidant capacity were analysed spectrophotometrically, while individual phenols were determined by liquid chromatography.
Different nutrition solution treatments and the number of harvest cycles had a significant effect on the content of the analysed bioactive compounds. The highest mass fraction (on fresh mass basis) of total phenols expressed as gallic acid equivalents (377.04 mg/100 g), total flavonoids expressed as catechol equivalents (279.54 mg/100 g), ascorbic acid (112.37 mg/100 g) and pigments (total chlorophylls 1.84, and total carotenoids 0.36 mg/g) as well as the highest antioxidant capacity expressed as Trolox equivalents (35.47 µmol/g) were recorded in the samples supplemented with nutrient solution (treatment NS2) and analysed after the third harvest.
This is the first time that stinging nettle leaves have been produced in a floating hydroponic system by controlled plant nutrition. We have set this type of nutritional manipulation with multiple harvest cycles as an innovative technique for the production of novel food with improved nutritional value that can be consumed as green leafy vegetables.
Fly bioash (FBA) as a by-product of biomass-fuelled facilities exhibits alkaline properties and is enriched with phytonutrients, thereby offering the potential to effectively ameliorate acidic and ...nutrient-deficient soils. However, concerns about health risks due to a potential FBA radioactive contamination are still not well studied, notably under field conditions. This study examined pH changes and concentrations of natural (238U, 232Th, 226Ra, 40K) and anthropogenic (137Cs) radionuclides after application of very alkaline (pH > 12) FBA in: (i) highly acid (pHKCl = 4.1) Luvisol and (ii) sunflower (Helianthus annuus L.) seeds, grown in organic farming and rain-fed conditions. FBA (originated from a modern cogeneration, fuelled on certified deciduous forest wood chips) was applied at increasing doses; 0, 4.5, 8.6, 13, and 17.2 t/ha. After 54 months of application, FBA significantly increased soil pHKCl by up to 1.8 unit and the seed yield by 15%, compared with no amended Control, without compromising soil electrical conductivity (salinity). The activity concentrations (Ac) of all observed radionuclides, measured using high-resolution gamma-ray spectrometry, were not altered under FBA application, neither in the surface (0–30 cm) Luvisol horizon nor in the sunflower seed. Moreover, the Ac of 238U, 232Th, and 137Cs in the seed were below detection limit, whereas the Ac of 40K and 226Ra were lower by up to 2.6 and 61 times, respectively, than their corresponding Ac in the soil treatments. The radiological footprint of FBA exhibited lower Ac for most of the observed radionuclides compared with both (i) Croatian non-arable topsoils (with reductions of 238U 3.6 times, 232Th 1.8 times, 226Ra 1.7 times, and 137Cs 1.5 times) and (ii) widely used mineral N/P/K fertilisers in conventional agroecosystems (with reductions of 238U 12.5 times; 226Ra 1.3 times, and 40K 2.4 times). Our findings provide evidence that the application of FBA as a soil conditioner does not pose radiological health or environmental risks, contributing to more sustainable agri-food production and circular bioeconomy. However, it is essential to conduct further studies to comprehensively investigate the effects of FBA application on soil and crop quality across diverse environmental conditions and extended spatiotemporal scales.
U radu je dat prikaz učinka petogodišnje provedbe operacije 10.1.15. PEG (primjena ekoloških gnojiva) s posebnim naglaskom na vrstu uporabe voćnjaci i maslinici. Voćnjaci, maslinici (i mješoviti ...trajni nasadi) zajedno su činili 40 % površina prijavljenih u PEG tijekom petogodišnjeg razdoblja 2018.-2022., a preostalih 60 % površina bili su vinogradi. Godišnje prijave voćarskih površina u PEG kretale su se od 389 ha (2018.) do 3542 ha (2022.), bilježeći stalni porast. Pripadajuća novčana vrijednost kretala se od 219.350,00 eura (2018.) do 1.994.854,00 eura (2022.), sveukupno 6.417.206,00 eura (48.350.439,00 kn). Za isto razdoblje, godišnje prijave maslinarskih površina u PEG kretale su se od 25 ha (2018.) do 709 ha (2022.), bilježeći stalni porast. Pripadajuća novčana vrijednost kretala se od 14.047,00 eura (2018.) do 399.330,00 eura (2022.), sveukupno 1.255.885,00 eura (9.462.466,00 kn). Uvođenje i provedba PEG-a u voćarstvu i maslinarstvu imala je značajne ekološke, tehnološke i financijske učinke. Potrebno je preispitati termin objave Pravilnika o IAKS mjerama jer konac veljače/početak ožujka ne ostavlja vremena da se proizvođači upoznaju s odredbama Pravilnika, te ispoštuju iste uvažavajući tehnološke rokove i samu implementaciju. Ostaje otvoreno pitanje: „Zašto PEG nije transformiran u Eko shemu, ugrađen u Pravilnik o IAKS mjerama 2023. i dat na moguće korištenje proizvođačima u 2023.?
The paper presents the effect of the five-year implementation of the 10.1.15 operation. AEF (application of ecological fertilizers) with special emphasis on the type of use in orchards and olive groves. Orchards, olive groves (and mixed permanent plantations) together accounted for 40% of the areas reported in the AEF during the five-year period 2018-2022, and the remaining 60% of the areas were vineyards. Annual applications of fruit growing areas in AEF ranged from 389 ha (2018) to 3542 ha (2022), recording a constant increase. The corresponding monetary value ranged from EUR 219,350 (2018) to EUR 1,994,854 (2022), a total of EUR 6,417,206 (HRK 48,350,439). For the same period, the annual registrations of olive areas in AEF ranged from 25 ha (2018) to 709 ha (2022), recording a constant increase. The corresponding monetary value ranged from 14,047 euros (2018) to 399,330 euros (2022), a total of 1,255,885 euros (9,462,466 HRK).The introduction and implementation of AEF in fruit growing and olive growing had significant ecological, technological and financial effects. It is necessary to review the date of publication of the Ordinance on IAKS measures because the end of February/beginning of March does not leave time for producers to familiarize themselves with the provisions of the Ordinance, and to comply with them, respecting the technological deadlines and the implementation itself? The question remains open: "Why was the AEF not transformed into an Eco scheme, incorporated into the Ordinance on IAKS measures in 2023 and made available for possible use by producers in 2023?"
This research aimed to assess the effect of applying digestate fractions and conventional mineral nitrogen (N) fertilizers on plant and soil properties, as well as potential nitrate leaching, in ...acidic soil over two consecutive years (2018 and 2019). The digestate fractions were obtained after the anaerobic co-digestion of maize silage and liquid cattle manure (LCM). Seven different treatments were applied to the maize crop in four replicates: unfertilized control (C), mineral fertilizer (MF), LCM, solid fraction of digestate (SFD), liquid fraction of digestate (LFD) and a mixture of SFD and LFD with MF (50% of total N from digestate fractions + 50% of total N from MF). The highest maize yields were achieved on average in 2018. Statistically, the highest dry grain yield was observed in the MF treatment (12.1 t ha−1) and in the mixtures of MF+SFD (11.0 t ha−1) and MF+LFD (11.8 t ha−1), while the lowest yield was achieved in both years in the C treatment (7.9 t ha−1). The N fertilizer replacement value was statistically highest on average in the MF treatment (100%) and in the mixtures of MF+LFD (80.5%) for both years. The experiment results could inform legal guidelines and standardize digestate application on agricultural land in Croatia and the European Union (EU).
Reakcija tla jedan je od najznačajnijih čimbenika koji utječu na topljivost i pristupačnost hraniva biljci. Provedeno istraživanje imalo je za cilj utvrditi u kojoj mjeri reakcija tla utječe na ...K/(Ca+Mg) u lišću vinove loze (Vitis vinifera L.), sorta Sauvignon bijeli (podloga SO4) na području Plešivičkog vinogorja (sjeverozapadna Hrvatska). Istraživanja su provedena u razdoblju 2009.-2011. godine na području Plešivičkog vinogorja na tlima jako kisele do kisele reakcije (lokacija Rečki gaj: pHKCl 3,54-5,01) i na tlu alkalne reakcije (lokacija Borička: pHKCl 7,01-7,41). Uzorci lišća za praćenje dinamike kalija, kalcija i magnezija te njihovog međusobnog odnosa uzimani su tri puta tijekom vegetacije (fenofaza cvatnja, šara i berba) u sve tri godine istraživanja. U sve tri godine istraživanja značajan utjecaj na K/(Ca+Mg) odnos u lišću vinove loze imala je reakcija tla te fenofaza rasta i razvoja. Širi odnos K/(Ca+Mg) u lišću vinove loze, u svim godinama istraživanja utvrđen je na tlu kisele reakcije (0,29, 0,58, 0,59) u odnosu na alkalno tlo (0,20, 0,40, 0,38). Najširi kationski odnos utvrđen je u fenofazi cvatnje (0,31-1,02), a najuži u fenofazi berbe (0,15- 0,34) u svim godinama istraživanja neovisno o reakciji tla.
Soil reaction is one of the most important factors that affects solubility and availability of nutrients to plants. The aim of the present research was to determine the effect of soil reaction on the K/(Ca+Mg) ratio in the grapevine (Vitis vinifera L.) leaves of the cultivar Sauvignon Blanc (rootstock SO4) in the Plešivica wine growing region (Northwest Croatia). The research was conducted in the period 2009-2011 in the Plešivica wine growing region on very acid to acid soil
(location Rečki gaj: pHKCl 3,54-5,01) and on alkaline soil (location Borička: pHKCl 7,01-7,41). Leaves samples for monitoring the dynamics of
potassium, calcium and magnesium and their mutual relationship, have been taken each year three times during vegetation (in the following phenological stages: flowering, veraison and harvest). A significant effect on the K/(Ca+Mg) ratio in the grapevine leaves was determined in respect to soil reaction and the phenological stage in all three years of research. The wider ratio of K/(Ca+Mg) in the leaves in all three years was determined on the acidic soil (0.29, 0.58, 0.59) in respect to
alkaline soil (0.20, 0.40, 0.38). The widest cation ratio was determined in the stage of flowering (0.31-1.02) while the most limited ratio was determined in the stage of harvest (0.15-0.34) in all research
years regardless soil reaction.
Stinging nettle (Urtica dioica L.) is a medicinal and edible plant species with a high economic potential. In most European countries nettle is still not produced commercially but is collected from ...natural habitats. This plant requires large amounts of nitrogen for its improved growth and satisfactory yield, which can result in accumulation of harmful nitrates and reducing of raw material quality. Mentioned problems can be solved by controlling the amount of nitrogen through fertilization, i.e. introduction of stinging nettle into agricultural production. The aim of this study was to determine the effect of three nitrogen fertilization doses (0, 100 and 200 kg N ha^sup -1^) on the chemical composition of cultivated nettle in the second year of growing. The harvest of the nettle for consumption in fresh form was carried out before flowering and six harvests were performed. It was found that cultivated nettle is a valuable source of potassium 2.27% K dry weight (dw), calcium (5.21% Ca dw) and iron (2765 ppm Fe dw). Fresh nettle herb contained high amounts of ascorbic acid 63.75 mg 100 g^sup -1^ fresh weight (fw) and total phenols (732.49 mg GAE 100 g^sup -1^ fw), correlated with its high antioxidant capacity (1936.58 mM Trolox L^sup -1^ fw). The highest nitrogen dose (200 kg ha^sup -1^) increased the content of crude protein and calcium, however resulted in higher nitrate content and lower values of dry matter, iron, total phenols and ascorbic acid. Therefore, fertilization with 100 kg N ha^sup -1^ could be recommended in production of nettle with a high nutritional value.
Three-year field fertilization trial with red beet (Beta vulgarisvar.conditiva) was carried out in a hilly-mountainous part of Croatia. The trial was set up according to the Latin square method with ...four fertilization treatments (unfertilized control, 5 kg m-2stable manure, and 50 and 100 g m-2NPK 5-20-30). The highest soil phosphorus content was obtained in the treatment with 100 g m-2NPK 5-20-30 or stable manure (up to 139 mg P2O5kg-1soil). In all three investigation years, the highest fresh and cooked red beet phosphorus content was recorded in the treatment with 5 kg m-2stable manure (400 and 358 mg P 100 g-1dry weight). The highest values were recorded in 2005, probably owing to very good agroecological conditions. Cooked red beet phosphorus content was 10 % lower than in fresh red beet in all trial years.
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