Mycorrhizal fungi can increase the effectiveness of a mineral fertilizer top dressing, positively affecting sweet pepper yield and quality. For this reason, an experiment was carried out between 2014 and 2016 to study the effect of top dressing doses and the inoculation of the root system with mycorrhizal fungi on the growth and yield of sweet pepper and the content of nutrients and macro- and microelements in the fruits. Root inoculation with Arbuscular Mycorrhizal Fungi (AMF) and mineral fertilizer doses were used as experimental factors with the following combinations: (1) mycorrhization: control (without AMF); AMF applied to the plant root zone during seedling production; AMF applied to the plant root zone after seedlings were transferred to pots; (2) top dressing doses: basic dose (100%); 50% of the basic dose; 25% of the basic dose. The sweet pepper fruits were harvested during physiological maturity. AMF inoculation of the root zone resulted in high sweet pepper yields of good quality. In particular, mycorrhizal fungi applied to the root system during seedling production positively affected the pepper yield and biometric characteristics, with fruits of the thickest pericarp and the largest mass. In the experimental units with AMF, the reduction in the top dressing fertilizer dose by 50% and 75% did not cause a statistically significant decrease in the yield of peppers and did not result in a deterioration of the biometric characteristics of the plants and fruits or a reduction in the biological value of the fruits. Despite the reduction in top dressing dose by 50% and 75%, AMF contributed to the accumulation of similar amounts of phosphorus in the sweet pepper fruits. The top dressing dose of 50% applied during seedling production to the experimental units with mycorrhizal fungi resulted in a significant increase in the content of potassium, calcium, and magnesium. A significant increase in the amount of sodium in the fruits was noted in the experimental units with mycorrhizal fungi applied to the roots when the seedlings were transferred to pots. To summarize, the application of mycorrhizal fungi to the pepper root zone during seedling production is recommended because it has a positive effect on the yield and its quality. In the unit with mycorrhiza, a lower dose of mineral fertilizers did not result in a significant decrease in the yield of pepper fruits.

Positively affecting crop quality and yields, amino acids used as plant stimulants play a special role in ensuring global food security. L-tryptophan (L-Try) and L-glutamic acid (L-Glu) are important biostimulants that increase the yield of field crops and vegetables. Carrot is one of the most important vegetables due to its production volume in the world (sixth most consumed vegetable) and its nutritional value. The response of different plant species to amino acid application varies. The literature mainly deals with the effects of ready-made products containing a mixture of several amino acids, with no exhaustive studies on the effects of individual amino acids on carrot quality and yield. This paper is based on a two-year field experiment (2019–2020), in which the effect of two amino acids, L-Trp (7.5 g·ha⁻¹) and L-Glu (60.0 g·ha⁻¹), on carrot (Daucus carota L.) was investigated. They were applied to the leaves (FA) or both to the soil and to the leaves (S + FA), separately, (L-Trp or L-Glu) or as a mixture (L-Trp + L-Glu). The control plot was treated with mineral fertilizers only. The research was conducted as a field experiment in a split-block design. The yield of carrot storage roots and their content of dry matter, protein, sugars, total soluble solids (TSS), and ascorbic acid were determined. The amino acids positively affected the yield of carrots compared to the control, but only the synergistic action of L-tryptophan and L-glutamic acid increased it significantly. On average, for both amino acids the S + FA application increased the protein content and the marketable yield of storage roots significantly more than in response to FA treatment. A significant increase in marketable yield compared to the control was found after the combined soil and foliar application (S + FA) of all amino acid combinations, but the L-Trp + L-Glu mixture worked best. The storage roots of carrots grown on the plot with L-Trp + L-Glu contained significantly more protein and TSS than those on the control plot. The content of TSS was also positively affected by L-Trp used on its own, while L-Glu increased the content of ascorbic acid. Amino acids applied to the leaves (FA) increased the content of total sugars in the carrot roots more than when applied both to the soil and to the leaves (S + FA). Of all treatment combinations, the synergistic action of L-Trp and L-Glu made it possible to obtain the highest yields of carrot storage roots, containing the most protein and total soluble solids.

» Articles | Agricultural Journals

Effect of plant density on the growth, development and yield of brussels sprouts (Brassica oleracea L. var. gemmifera L.)

Potatoes are one of the most important sources of nutrients worldwide, but excessive doses of industrial fertilizers are usually used to achieve higher yields. Soil biostimulants are an increasingly used alternative for reducing fertilizer doses and growing healthy agricultural products. In this study, we examined the effects of humic substances (Agriful) and beneficial bacteria (Groundfix) based biostimulants applied by dripping irrigation on the yield and quality of potato tubers in comparison with the conventional N fertilization system. The small trail field experiment was founded in the growing season of 2020 in the Botanical Garden of the Slovak University of Agriculture in Nitra. The highest tubers yield had the combination of biostimulants and N fertilizer – 195.16% above to control. Simultaneously this combination reached an increase in refractometric dry matter content, starch content – 3.6%, and vitamin C content – 20% increase above to control. The Groundfix variant had the highest antioxidant activity with a 16.2% difference compared to the conventional nitrogen fertilization variant. These results show the positive effect of applied biostimulants on the yield and quality of cultivated potatoes.

Chili peppers are globally cultivated for their rich bioactive compound profile. This study investigates the impact of two biostimulants, Humix^® and Energen, on Capsicum chinense ‘Habanero Orange’ and Capsicum annuum ‘Kristian’, focusing on quantitative and qualitative parameters. Conducted over two years with three annual harvests, the research assesses the effects of biostimulant application on yield, fresh fruit number, fruit weight, drying ratio, capsaicin, dihydrocapsaicin, and ascorbic acid content (via HPLC-DAD analysis), as well as carotenoid levels (via spectrophotometric analysis). Biostimulant application significantly increased (p ≤ 0.05) total yields and capsaicin levels. Harvest timing also influenced dihydrocapsaicin and capsaicin levels, with the third harvest showing the highest values (p ≤ 0.001). The effects on ascorbic acid and carotenoids were variable and depended on genotype, harvest, and treatment. Thus, our study provides insights into the dynamic responses of Capsicum species to biostimulants under variable climatic conditions, contributing new knowledge to agricultural practices and the scientific understanding of biostimulant effects in Capsicum production.