Katarzyna Kucińska

Organic agriculture is considered one of the elements of sustainable food production and consumption, mainly due to its limited impact on the natural environment. At the same time, the quality features of organically produced foods, especially sensory attributes and health promoting values, are important factors determining consumers’ interest, and therefore play a key role in the organic sector’s development. The aim of this study was to investigate the sensory characteristics and concentrations of sugars and selected health-promoting bioactive compounds of organic courgette compared to conventionally grown courgette. In addition, untargeted metabolomic analysis of the courgette fruits was performed. The results of this study did not show a significant effect of the horticultural system (organic vs. conventional) on the concentrations of vitamin C, carotenoids, and chlorophylls in the courgette fruits. However, the fruits from the organic systems were significantly richer in sugars when compared to the conventionally cultivated ones (p = 0.038). Moreover, the organic fruits fertilized with manure contained significantly higher amounts of polyphenols, including gallic acid (p = 0.016), chlorogenic acid (p = 0.012), ferulic acid (p = 0.019), and quercetin-3-O-rutinoside (p = 0.020) compared to the conventional fruits. The untargeted analysis detected features significantly differentiating courgette fruits depending on the cultivar and horticultural system. Some significant differences in sensory values were also identified between fruits representing the two cultivars and coming from the horticultural systems compared in the study. Conventional courgettes were characterized by the most intensive peel color and aquosity, but at the same time were the least hard and firm compared to the fruits from the two organic systems. There was also a trend towards higher overall quality of the organically grown fruits. The presented study shows that the organic and conventional courgette fruits differ in a number of quality features which can influence consumers’ health and purchasing choices.

Courgette is considered as a low-calorie vegetable with health-promoting properties. However, scientific publications focused on the profile and content of bioactive compounds in courgette, as well as the potential fruit quality modulating factors, are rare. Due to the high adaptability of courgette to weather and agronomic conditions, it is produced on a global scale. The aim of this study was to analyse the impact of organic versus conventional agronomic practices on the concentration of selected antioxidants in courgette fruits. Fruits of two courgette varieties (Astra Polka and Nimba) produced in an organic and conventional system were tested by high performance liquid chromatography (HPLC) to determine the content of polyphenols (flavonoids and phenolic acids), carotenoids, chlorophylls, and vitamin C. Organic courgette fruits were characterised by their significantly higher content of phenolic acids and flavonoids when compared to the conventionally grown fruit. The organic cultivation might be a good method to increase concentration of bioactive compounds with antioxidant properties in courgette fruits. Nevertheless, the identified trends should be further confirmed, with attention paid to other courgette varieties, as well as to the potential interactions between the plant genotype, agronomic system and the location-specific growing conditions.

The present study was conducted to assess the effect of various multinutrient foliar fertilization treatments on nutrient accumulation in the roots and leaves of sugar beet. The field experiment was performed in two growing seasons (2013 and 2014) in the southeastern region of Poland. The experiment was conducted as a randomized block design with four replications. To determine the content of the selected nutrients (Si, N, P, K, Mg, and Ca), samples of leaves and roots were collected during harvest. Fertilization treatments applied on the plants’ leaves affected the silicon (Si) content in the roots of sugar beet and the total Si uptake. Moreover, foliar fertilization had a significant effect on the P content in the leaves and the N and K contents in the roots. The Si content in the sugar beet leaves and roots ranged from 0.55 to 1.97 g kg⁻¹ dry matter (d. m.) and from 0.49 to 1.59 g kg⁻¹ d. m., respectively. The total Si uptake ranged from 20.3 to 46.7 kg ha⁻¹. Most of the Si content taken up with each fertilization variant was accumulated in the roots. The yield of pure sugar was not correlated with the Si content in the leaves and roots.

THE EFFECT OF SILICON FOLIAR FERTILIZATION IN SUGAR BEET – Beta vulgaris (L.) ssp. vulgaris conv. crassa (Alef.) prov. altissima (Döll)

In presented paper changes in the sugar production and in the nursery of the sugar beet in the EU brought about were described with implementing the reform of the market of the sugar. An too small interest in limiting the sugar production in 2007 caused the yr the European Commission modified principles of the reform and a possibility of the resignation led farmers from the right into the cultivation of the sugar beet in exchange for high bonuses in the framework of the so-called farmer’s initiative. At the same time they enabled sugar factories to assume this initiative under the condition of limiting the sugar production, in case of Poland, by the 13.5%. All sugar concerns took advantage of this possibility. However it turned out, that considerable part of farmers, on account of the low profitability of the cultivation of the sugar beet, doesn’t want to plant this plant. In April 2008 yr, sugar concerns had a problem with contracting the essential amount of the raw material. Therefore they persuaded farmers which relinquished their right to the cultivation to produce the raw material in frames of the limit of the sugar factory. However such a situation can cause, that Poland will become the net importer of the sugar, or else the domestic production in 2008 will be shorter than the demand

Trudna sytuacja ekonomiczna producentów buraka cukrowego stwarza konieczność minimalizowania nakładów w uprawie tego gatunku. Przedstawione wyniki badań oparto na statycznym doświadczeniu płodozmianowym trójpolowym, w którym zastosowano dwie formy nawozów organicznych (obornik, słoma + międzyplon facelia oraz obiekt bez nawozów organicznych) i nawożenie azotem mineralnym w ilościach 0, 60, 90, 120, 180 kg N/ha. W ocenie efektywności nawożenia zastosowano kategorię ekonomiczną nadwyżki bezpośredniej powszechnie stosowaną w kalkulacjach niepełnych. Wyniki umożliwiają ocenę opłacalności porównywanych wariantów. W badaniach trzyletnich 2000–2002 prowadzonych w Zakładzie Doświadczalnym Katedry Agronomii SGGW w Chylicach k. Warszawy najlepszą efektywność w produkcji buraka cukrowego uzyskano przy zastosowaniu obornika (30 t/ha) i azotu mineralnego w dawce 120 kg N/ha.