In modern agriculture, besides providing high and stable yields, it is imperative to produce products with a high nutritive quality. The goal of this study was to determine the effect of different ...fertilization regimes on the macro- and micronutrients in beetroot. A 3-year field trial was set up according to a Latin square method with four types of fertilization (unfertilized control, 50 t stable manure ha-1, and 500 and 1,000 kg NPK 5-20-30 ha-1). The mineral content was determined as follows (mg 100 g-1 in fresh weight of beetroot): 14-29 P, 189-354 K, 18-34 Ca, 17-44 Mg, 0.67-1.83 Fe, 0.41-0.65 Mn and 0.28-0.44 Zn. The highest beetroot P content was determined for the treatment with stable manure, especially in a year with dry climatic conditions. The highest beetroot K content was determined for the treatment with 1,000 kg NPK 5-20-30 ha-1, but at the same time for the same treatment, a general decreasing trend of micronutrient content was determined, due to the possible antagonistic effect of added potassium. For better mineral status of beetroot, application of combined mineral and organic fertilizers supplemented with additional foliar application of micronutrients can be suggested.
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.
This study examines genetic diversity and structure of a Croatian garlic germplasm collection using 13 simple sequence repeat (SSR) markers. A total of 71 alleles were observed across 64 accessions ...representing 3 Croatian regions (Istria, Dalmatia and continental Croatia) and 16 foreign landraces, with an average of 5.46 alleles per locus. Among the 80 accessions analysed, 61 distinct multilocus genotypes (MLG) were identified, of which 51 represented unique genotypes and the remaining accessions were divided into 10 MLG groups, comprising potential duplicates or redundant genotypes. Model-based Bayesian and hierarchical UPGMA clustering approaches revealed five major groups within the collection which partially correlated with geographical origin. The analysis of molecular variance (AMOVA) showed that the majority (87.71%) of the total molecular diversity is within the Croatian groups of accessions, even though a significant share (12.29%) of diversity derived from genetic diversity among groups. These results support regional structuring, as well as the existence of significant diversity within local populations. This study is the first comprehensive report on an extensive evaluation of genetic resources of garlic maintained by Croatia with the aim of setting the course for future preservation strategies with particular emphasis on the value of diversity in the context of climate change both on macro and micro levels.
Soil is a non-renewable resource, so it should be taken care of it. High quality food with sufficient yield for a growing human population can be produced only if plant nutrients are added to the ...soil by fertilizers to increase soil fertility, but the fertilizers have to be used economically, with the aim of raising the nutrient content available in the soil in order to meet plants' needs. The goal of the present investigation was to determine the effect of application of organic and mineral fertilizers as well as the effect of research environment on micronutrient content in red beet root. A field trial (2003-2005) was set up in a hilly part of Croatia according to the Latin square method, with four types of fertilization (control, 50 t stable manure*ha.sup.-1, 500 and 1,000 kg NPK 5-20-30*ha.sup.-1). After digestion of plant material with concentrated HNO.sub.3, iron, manganese, and zinc were determined by an atomic absorption spectrophotometer (AAS). The highest average red beet root micronutrient contents (270 mg Fe*kg.sup.-1 in dry matter, 96 mg Zn*kg.sup.-1 in dry matter, and 53 mg Mn*kg.sup.-1 in dry matter) were determined in the first research environment (Braljevica in 2003) with low potassium soil content. There was a general decreasing trend in contents of the studied micronutrients (Fe, Mn and Zn) with NPK 5-20-30 fertilization (and by application of high doses of potassium), certainly due to antagonistic activity with potassium. It is suggested to fertilize with both 500 kg NPK 5-20-30*ha.sup.-1 and microelement fertilizers.
Variable content of bioactive compounds and minerals is the main problem in the production of vegetables as functional food, due to genetic, abiotic and agronomic factors (especially fertilization), ...which may affect the nutritional and medicinal value of vegetables. In order to achieve the higher yield, producers often apply large amounts of nitrogen fertilizer, which can result in the accumulation of nitrate, reducing the quality of broccoli. There are no results about the content of bioactive compounds and minerals in broccoli inflorescence grown on the principles of Good Agricultural Practices in Croatia. Therefore, the research has been set up to determine the effect of nitrogen fertilization on the content of glucosinolates, some minerals (potassium, calcium and nitrogen) and nitrate levels in the broccoli top inflorescence during different growing seasons. The two factorial field trials were conducted in spring/summer and summer/autumn growing seasons in 2009 according to a randomized complete block design with four replications. Two broccoli cultivars (Marathon and Parthenon) and four levels of nitrogen fertilization (0, 60, 120 and 240 kg/ha) were tested. There was a significant effect of cultivar and rate of nitrogen fertilization on the nutritional quality of broccoli top inflorescence in both growing seasons. The average values of total glucosinolates per g of dry mass (12.82 µmol) and calcium (1.12 %) in broccoli top inflorescence were significantly higher during the spring/summer growing season. The prevailing glucosinolates in that growing season were glucobrassicin and neoglucobrassicin. In the summer/autumn growing season, higher amounts of nitrate per kg of fresh mass (553 mg), nitrogen (5.40 %) and glucoraphanin per g of dry mass (5.4 µmol) were achieved and the dominant individual glucosinolates were glucoraphanin and glucobrassicin. Combination of Marathon with N 120 or 240 kg/ha, which resulted in the highest values of determined glucosinolates and some minerals, with nitrate content in the allowed range, could be recommended for conventional broccoli production under climate conditions of northwestern Croatia. Key words: Brassica oleracea L. var. italica, growing season, glucoraphanin, neoglucobrassicin, potassium, calcium, nitrogen
The research aim was to determine the influence of different organic and mineral fertilization treatments and post-harvest treatments on the content of nitrogen and crude proteins in the edible part ...of beetroot (Beta vulgaris var. conditiva). A field trial (2003-2005) was set up in a hilly part of Croatia according to the Latin square method with four types of fertilization (control, 50 t ha-1 stable manure, 500 and 1000 kg ha-1 NPK 5-20-30), while treatments involved harvested fresh beetroot and stored fresh beetroot. The highest dry weight (DW) content was determined in climatologically favourable 2004 (average 14.8% DW) and in the treatment with 1000 kg ha-1 NPK 5-20-30 (15.6% DW) in harvested beetroot. In 2004 and 2005, the highest levels of nitrogen and crude proteins in harvested beetroot were determined in the treatment with 1000 kg ha-1 NPK 5-20-30 (2.41 and 2.43 g N kg-1 in fresh weight and 15.07 and 15.21 g crude proteins kg-1 in fresh weight, respectively). Regardless of fertilization treatment or studied year, nitrogen and crude protein contents were higher in stored than in harvested beetroot, by 12% on average. The lowest crude protein content was determined in treatment with stable manure what confirmed that protein content decreased by organic fertilization. It can be concluded that beetroot lost some water during the storage period, which increased its content of nitrogen and crude proteins in fresh weight and thus increased the nutritional quality of beetroot as a functional food.
Ljekovite i aromatične vrste tradicijski i generacijski nezaobilazni su dio svakog ekološkog povrtnjaka, a njihova višestruka funkcija sve je češći predmet znanstvenih istraživanja. Osim što svojim ...intenzivnim mirisom i raskošnim izgledom obogaćuju povrtnjak, privlače korisne kukce i oprašivače čime se održava prirodna ravnoteža i potiče bioraznolikost. Posijane ili posađene u blizini povrtnih vrsta kroz združivanje usjeva ili konsocijacije, mogu poticajno djelovati na njihov rast i razvoj, što se očituje kroz pozitivne alelopatske odnose i repelenciju štetnih organizama tla, štetnika na biljkama i uzročnika bolesti (gljivice i bakterije). Premda, zbog alelokemikalija koje aromatične vrste izlučuju mogu djelovati i inhibirajuće na rast i razvoj drugih vrsta u blizini. Zbog toga je prilikom združivanja potrebno poznavati karakter susjedskih odnosa aromatičnih i povrtnih vrsta. Od nekih ljekovitih i aromatičnih biljaka mogu se pripremati botanički pripravci, koji stimulativno djeluju na rast i razvoj biljaka te jačanje njihove otpornosti (bio-gnojiva) ili se koriste u svrhu suzbijanja bolesti i štetnika (bio-insekticidi).
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.
The nutritional value of sweet potato leaves (Ipomoea batatas L.) has recently been emphasised as their anti-oxidant and phenolic compounds can improve human health and provide nutritional benefits. ...This has increased the interest of the food industry and of consumers in using sweet potato greens as a functional food. To increase the level of phenolic compounds in sweet potato leaves, we studied the influence of potassium (K)-fertilisation at different N:K ratios namely 1:1 (control), 1:2.5, or 1:5 on the phenolics contents and corresponding anti-oxidant activities of two cultivars of sweet potato, 'Bat1'and 'Boniato'. In general, enhanced K-fertilisation increased the level of phenolic compounds and the corresponding anti-oxidant activity. However, the two cultivars differed in their response to K-fertilisation. Phenolic acids were increased (by approx. 20%) in 'Bat1' only after the application of N:K at a ratio of 1:5, while K-fertilisation at all rates increased the flavonoid contents of both cultivars (by approx. 300%). Our results could be useful for sweet potato producers who wish to make informed decisions on which cultivar and/or mineral fertiliser regime to choose in order to produce sweet potato leaves of the desired nutritional quality.
PDF
