# Effect of Biostimulants on the Yield and Quality of Selected Herbs
## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Factor** & \(\mathbf{c_{dm}}\) & \(\mathbf{c_{bs}}\) & \(\mathbf{c_{rs}}\) & \(\mathbf{c_{O}}\) & \(\mathbf{c_{L}}\) & \(\mathbf{c_{N}}\) \\ \hline Treatment (A) & 0.061 & 0.381 & 0.791 & 0.379 & 0.803 & \textless{}0.001 \\ Species (B) & 0.096 & 0.887 & \textless{}0.001 & 0.324 & \textless{}0.001 & 0.016 \\ Interaction (A \(\times\) B) & 0.520 & 0.340 & 0.145 & 0.325 & 0.318 & \textless{}0.001 \\ \hline \hline \end{tabular} \(c_{dm}\)—Dry matter content, \(c_{bs}\)—total sugar content, \(c_{rs}\)—reducing sugar content, \(c_{O}\)—organic acid content, \(c_{L}\)—L-ascorbic acid content, \(c_{N}\)—nitrate (V) content.  
\end{table} 
Table 2: \(p\)-Value of ANOVA for the nutrient composition of herbage in the analyzed herb species. Figure 1: Effect of biostimulants on plant height, fresh herbage weight, and yield in the analyzed herb species: a–  
According to [PERSON] et al. [33], the concentration of L-ascorbic acid in herbs is significantly affected by the species and cultivation method. In the present study, marjoram was characterized by the highest concentration of L-ascorbic acid (39.7 mg 100 g\({}^{-1}\) FM on average). The L-ascorbic acid content of the herbage was not significantly modified by the biostimulants. The concentration of L-ascorbic acid increased in marjoram treated with Maximus Amino Protect (44.6 mg 100 g\({}^{-1}\) FM), whereas it was significantly lower in lemon balm in all treatments and in summer savory in the control treatment and in the treatment  
with Maximus Amino Protect. Similar L-ascorbic acid concentrations were determined by [PERSON] et al. [31] in lemon balm (32.1-76.3 mg 100 g\({}^{-1}\) FM depending on the cultivation method), and [PERSON] et al. [15] (9.8-79.4 mg 100 g\({}^{-1}\) FM in lemon balm and 23.6-74.5 mg 100 g\({}^{-1}\) FM in marjoram). In a study by [PERSON] et al. [33], the L-ascorbic acid content of lemon balm herbage ranged from 4.2 to 5.3 mg 100 g\({}^{-1}\) FM. The concentrations of organic acids in the analyzed herb species were not significantly affected by the experimental factors or their interaction. Summer savory herbage harvested in the control treatment had the highest organic acid content (0.10 g 100 g\({}^{-1}\) FM). The concentration of organic acids was the lowest (0.06 g 100 g\({}^{-1}\) FM) in summer savory and marjoram treated with Calleaf Aminovital. According to Commission Regulation (EU) No. 1881/2006 of 19 December 2006 [34], which set the maximum levels for certain contaminants in foodstuffs, the maximum nitrate levels in lettuce plants grown in a greenhouse and in the field are 3500-4500 N-NO\({}_{-3}\) kg\({}^{-1}\) FM and 2500-4000 N-NO\({}_{-3}\) kg\({}^{-1}\) FM, respectively. Such standards have not been established for herbs and spices. In the current study, the nitrate content of herbage in the analyzed herb species was relatively low. Proper plant nutrition promotes good plant development and growth, as well as an adequate circulation of matter and the reduction of harmful residues. Nitrate levels were significantly affected by herb species, ranging from 1880 N-NO\({}_{-3}\) kg\({}^{-1}\) FM in summer savory herbage to 2282 N-NO\({}_{-3}\) kg\({}^{-1}\) FM in marjoram herbage on average. The use of Calleaf Aminovital and Maximus Amino Protect in the cultivation of spice plants reduced the accumulation of nitrates. The average differences were 22.8% and 18.7%, respectively, relative to control treatment plants. An analysis of the interaction between the experimental factors revealed that the significantly highest amounts of nitrates were accumulated in lemon balm in the control treatment (2646 N-NO\({}_{-3}\) kg\({}^{-1}\) FM) and the lowest amounts were in summer savory treated with Maximus Amino Protect (1646 N-NO\({}_{-3}\) kg\({}^{-1}\) FM). [PERSON] et al. [32] reported similar nitrate levels in summer savory (1700 N-NO\({}_{-3}\) kg\({}^{-1}\) FM). Macronutrients play important functions in the body, including the regulation and maintenance of the acid-base balance.