## 3 Results and Discussion
### Chemical Composition of Broccoli Plants
#### 3.3.1 Macronutrient Content  
The effect of soil type on the macronutrient (mineral) content of the edible parts of broccoli plants is presented in Table 2 and Figure 3. It was found that macronutrient concentrations were not significantly affected by soil type, but the accumulation of macronutrients varied across the edible plant parts (florets, leaves, and stalks). The uptake of potassium and calcium by plant parts may vary depending on soil type. Plant nutrient availability is determined by nutrient concentrations in the soil solution, and nutrient ratios [24].  
According to [PERSON] and [PERSON] [25], nitrogen is one of the major nutrients in crop production. It affects seedling emergence and leaf area expansion. In the present experiment, nitrogen accumulation was significantly lower in stalks than in leaves (by approx. 32% on average) and florets (by approx. 35% on average). Nitrogen accumulation was highest in the florets of broccoli plants grown in soil II (4.9 g 100 g\({}^{-1}\) DM on average), and lowest in the florets of broccoli plants grown in soil III. An analysis of the content of magnesium and phosphorus in the edible parts of broccoli plants revealed similar relationships. On average, florets contained from 18 to 19 g 100 g\({}^{-1}\) DM of magnesium, and from 0.37 to 0.45 g\({}^{-1}\) DM of phosphorus; the respective values were around 11% and 15% lower in leaves (excluding broccoli plants grown in soil I--20 g 100 g\({}^{-1}\) DM and 0.40 g 100 g\({}^{-1}\) DM), and around 36% and 37% lower in stalks. Potassium accumulation was generally highest in stalks (from 3.27 to 3.35 g 100 g\({}^{-1}\) DM on average), although the florets of broccoli plants grown in soil II had the highest potassium content (3.53 g 100 g\({}^{-1}\) DM). Potassium content was lowest in leaves, around 21% lower on average than in stalks. In turn, the accumulation of calcium and sulfur was highest in leaves (from 1.45 to 2.24 g 100 g\({}^{-1}\) DM and from 0.87 to 0.95 g 100 g\({}^{-1}\) DM, respectively). In comparison with leaves, calcium content was around 76% lower in stalks and around 88% lower in florets, whereas sulfur content was around 52% lower in stalks and around 31% lower in florets. Similar results were reported by [PERSON] et al. [26]. Calcium is phloem immobile, similarly to manganese, and the delivery of these nutrients to developing florets is limited in relation to other mineral elements, such as zinc and phosphorus [27,28].  
Figure 2: Effect of soil type on broccoli yields: a, b—various letters denote significant differences at \(p<0.05\) ([PERSON]’s test); I—Eutric Cambisol; II—Albic Luvisol (Arenic); III—degraded chernozem.  
Figure 3: Effect of soil type on the macronutrient content of broccoli stalks, leaves and florets: a, b, c, d, e, f—various letters denote significant differences at \(p<0.05\) ([PERSON]’s test); I—Eutric Cambisol; II—Albic Luvisol (Arenic); III—degraded chernozem.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Factor** & **N** & **P** & **K** & **Mg** & **Ca** & **S** \\ \hline Soil (A) & 0.666 & 0.536 & 0.463 & 0.694 & 0.663 & 0.665 \\ Edible plant part (B) & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 & \textless{}0.001 \\ Interaction (A \(\times\) B) & 0.008 & 0.250 & \textless{}0.001 & 0.053 & \textless{}0.001 & 0.439 \\ \hline \hline \end{tabular}
\end{table}
Table 2: \(p\)-value in ANOVA of the macronutrient content of broccoli florets, leaves, and stalks.