*3.3. E*ff*ect of Nitrogen Fertilization on Dry Matter Yield of Miscanthus* × *Giganteus*

Nitrogen fertilization significantly contributed to an increase in the dry matter yield of leaves (*p* = 0.0000). The nitrogen fertilization and lack of fertilization of biomass sampling was characterized by an increasing tendency in the dry mass of rhizomes and aboveground parts of plants. The dry mass of the stems grew faster than that of the leaves over the whole vegetation period (Figure 7). The highest yield growth dynamics of the whole plant was observed between August and September (Table 6, Figure 8).

**Figure 7.** Dry mass yield of the leaves and stems during the vegetation period in the years 2014–2016 (average for years).


**Table 6.** The yield of the dry mass of *Miscanthus* <sup>×</sup> *giganteus* (kg m<sup>−</sup>2) (average for years 2014–2016).

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**Figure 8.** Dry mass yield of the rhizomes and the aboveground part of the plant during the vegetation period of the years 2014–2016 (average for years).

The dry mass of aboveground parts of plants (*p* = 0.0153) and rhizomes (*p* = 0.0125) in 30-day intervals significantly differentiated from June to November, in which we obtained the highest values in December (Table 6, Figure 8). In July, the dry matter of leaves was slightly greater than that of the stems, and from this month the increase in the dry matter of stems was greater than that of the leaves. The period between June and July and the November and December vegetation days, constituted 29%

of the entire vegetation period. During this time, a more than 18% increase in the dry weight of the rhizomes and aboveground parts was observed.
