The Usefulness of Mixtures with Festulolium braunii for the Regeneration of Grassland under Progressive Climate Change

: The climate warming and changes in weather patterns in Europe are negatively affecting the structure of grassland swards. The disappearance of valuable forage grasses can be observed. Therefore, in order to keep grassland productivity high, high-yielding grasses of good quality that are resistant to changes in the weather are being sought. At the moment there are few publications which present the long-term inﬂuence of changing weather conditions on meadow sward structure and its fodder value. This study aimed to assess the suitability of grass mixtures with Festulolium braunii for grassland renewal by full tillage on organic soil, taking into account atmospheric conditions. The experiments were carried out in the years 2009–2018 on a meadow complex located on organic soil in the Randow river valley, near Ramin (Germany). Grassland restoration was carried out by the method of full cultivation in three experiments with different proportions of Festulolium braunii and Lolium perenne (the existing grassland was eliminated and seeds of a new grass mix were sown). The meadow experiments were established using the method of random blocks in four repetitions Detailed studies included: ﬂoristic composition of meadow sward, fresh and dry mass yields, and content of: crude protein, soluble sugars, raw ﬁber, and net energy NEL (net energy lactation) concentration. Festulolium braunii , Poa pratensis , Dactylis glomerata , and Phleum pratense proved to be more resistant to low temperatures in winter and excess water in spring than Lolium perenne . The largest production potential of fresh and dry mass was found in mixtures with a high content of Festulolium braunii Festulolium braunii tolerates varied and unfavorable weather conditions (frosts during snowless winters, spring frosts and waterlogging, and droughts) very well and provides a stable good quality sward yield (favourably affected the carbohydrate and protein content of the sward). Lolium perenne , on the other hand, decreases its share in the sward under unfavorable weather conditions.


Introduction
In recent decades there has been a noticeable warming of the Earth's climate. It is associated with changes in weather patterns, e.g., in the distribution and amount of place is taken by Poa pratensis. The conversion processes in these habitats are intensified by the progressing climatic changes. Therefore, there is a need to conduct research with the selection of grass species for meadow mixtures on organic soils [34,35].
In recent years, due to climate change, there has been increasing interest in forgotten grass species and grass hybrids in many countries. Interspecific hybrids have intermediate parental characteristics-high yields of good quality and resistance to unfavorable habitat conditions. Festulolium braunii hybrids obtained from crossing meadow fescue and perennial ryegrass are one of them [36][37][38]. Festulolium braunii hybrids are characterized by high productivity and persistence in sward [39][40][41][42][43][44]. They respond well to drought, frost and periodic excessive moisture [38,[45][46][47][48][49]. However, some studies indicate that prolonged drought may limit the growth of some Festulolium hybrids [50,51]. Festulolium braunii is used with mixtures for alternate grassland and used for renovation of permanent grasslands [52][53][54][55]. The meadows have consisted so far of a mixture of high-yielding grasses, but are demanding in terms of habitat, fertilisation and specific climatic conditions. These grasses adapt poorly to weather changes and disappear from the meadow sward, which is confirmed by field observations. Therefore, it is important for agricultural practice to develop alternative meadow sward mixtures with good fodder value and at the same time adapted to periodic summer drought, high humidity in winter and spring, and warm, snowless winters with short but strong frosts, and responding well to increases in atmospheric CO 2 . These conditions can be met by hybrids of appropriately selected grasses. The suitability of hybrids in shaping the height and quality of sward yields should be tested under different habitat and weather conditions over a sufficiently long period of time.
The aim of the study was to assess the suitability of grass mixtures with different proportions of the Festulolium braunii hybrid for grassland renewal on organic soil. It was also important to evaluate the resistance of Festulolium braunii in comparison to Lolium perenne to different weather conditions and the influence of this hybrid on the quantity and quality of meadow sward yields.

Location and Soil Conditions of Study Objects
The study was carried out on grasslands located on organic soil of peat-muck soil type, subtype-mucky soil in the Randow river valley, near the vicinity of Ramin (Germany), ( Figure 1). Grasses intended for mowing on peat-muck soils, only shortly after sowing, are characterized by a stable species composition [32,33]. High grasses (higher than 100 cm) are the first to disappear (Festuca pratense, Phleum pratense, Dactylis glomerata), and their place is taken by Poa pratensis. The conversion processes in these habitats are intensified by the progressing climatic changes. Therefore, there is a need to conduct research with the selection of grass species for meadow mixtures on organic soils [34,35].
In recent years, due to climate change, there has been increasing interest in forgotten grass species and grass hybrids in many countries. Interspecific hybrids have intermediate parental characteristics-high yields of good quality and resistance to unfavorable habitat conditions. Festulolium braunii hybrids obtained from crossing meadow fescue and perennial ryegrass are one of them [36][37][38]. Festulolium braunii hybrids are characterized by high productivity and persistence in sward [39][40][41][42][43][44]. They respond well to drought, frost and periodic excessive moisture [38,[45][46][47][48][49]. However, some studies indicate that prolonged drought may limit the growth of some Festulolium hybrids [50,51]. Festulolium braunii is used with mixtures for alternate grassland and used for renovation of permanent grasslands [52][53][54][55]. The meadows have consisted so far of a mixture of high-yielding grasses, but are demanding in terms of habitat, fertilisation and specific climatic conditions. These grasses adapt poorly to weather changes and disappear from the meadow sward, which is confirmed by field observations. Therefore, it is important for agricultural practice to develop alternative meadow sward mixtures with good fodder value and at the same time adapted to periodic summer drought, high humidity in winter and spring, and warm, snowless winters with short but strong frosts, and responding well to increases in atmospheric CO2. These conditions can be met by hybrids of appropriately selected grasses. The suitability of hybrids in shaping the height and quality of sward yields should be tested under different habitat and weather conditions over a sufficiently long period of time.
The aim of the study was to assess the suitability of grass mixtures with different proportions of the Festulolium braunii hybrid for grassland renewal on organic soil. It was also important to evaluate the resistance of Festulolium braunii in comparison to Lolium perenne to different weather conditions and the influence of this hybrid on the quantity and quality of meadow sward yields.

Location and Soil Conditions of Study Objects
The study was carried out on grasslands located on organic soil of peat-muck soil type, subtype-mucky soil in the Randow river valley, near the vicinity of Ramin (Germany), (Figure 1). The Randow river valley is filled with fluviogenic peatland, which was sanded in the past. The surface layer of 30-50 cm is made up of mineral-organic material (post-glacial sand with gravel mixed with muck). The formed mineral-organic layer has features typical for mucky soils. The thickness of the peat bog ranges from 90 cm to 220 cm. The grassland belongs to a farm: Raminer Agrar GmbH&Co (Ramin, Mecklenburg-Vorpommern, Germany).

Meteorological Conditions during the Study Period
According to Grzegorczyk [12], the sum of precipitation and temperature distribution are among the most important factors modifying the development of plants and their yield. Meteorological data from weather station in Löcknitz (Germany) for the years 2009-2018 and in the multi-year 1980-2018 (Table 1) indicate large differences in air temperature and sum of precipitation during the study. The average air temperature and precipitation during the whole vegetation period in the years of the study were higher than in the corresponding multi-year period. In the study years, the year 2018 with the average temperature in the vegetation period (IV-X) of 17.2 • C was the warmest, and the years 2013 and 2014 were also warm with the average air temperature of 16.4 and 16.7 • C, respectively, in the plant growth period ( Table 1). The average values for the vegetation period as well as for the whole year exceeded the multi-year average value by more than 3 • C. The months with high air temperature in 2009 were July and August, where the average temperature was 19.4 and 19.6 • C respectively; in 2010 was July; in 2011 was August; in 2013 were June and July; in 2014 a period July-September; in 2016 a period in May-September; and in 2017 a period July-August. In the warmest year 2018, the high average air temperature was from May to the end of September, where the average temperatures were much higher than the averages for the same period in the 1980-2018 multi-year (Table 1). Table 1. The average monthly air temperature ( • C) and monthly sum of precipitation (mm). I  II  III  IV  V  VI  VII VIII IX  X  XI  XII  I-XII IV-X In all the years of the study a much higher sum of precipitation than in multi-year period was recorded in 2017, 2011 and 2010 ( Table 1). The sum of precipitation in those In the remaining years, the amount of precipitation in the vegetation period was similar to those recorded for the multi-year period. In the wettest year 2017 the highest sum of precipitation was recorded in the months from May to August, in which the precipitation exceeded the sum of the multi-year period by 230 mm. In the analysed period there was much less rainfall in April than in many years. The rainfall in this month is important for the yield of the first swath.

Characteristics of Field Experiments
Grassland renewal was carried out using the full cultivation (tillage) method (the existing grassland was eliminated and seeds of a new grass mix were sown). The results presented in this paper relate to three single-factor experiments from the vegetation seasons 2009-2011, 2012-2013 and 2013-2018. The meadow experiments were established using the method of random blocks in four repetitions ( Table 2). The area of a single plot was 10 m 2 . The following grass species were used for grassland renewal: Festulolium braunii, Lolium perenne, Poa pratensis, Phleum pratense, Dactylis glomerata. The composition of grass mixtures used for sowing individual objects of the experiment is presented in Table 3. The pratotechnical treatments carried out in the experiment included: leveling, rolling, fertilizing and mowing. During the spring leveling and rolling, a multi-component fertilizer was applied-NPK (Mg S) 5-16-24 (4-7), in which 15 kg N, 21 kg P, 60 kg K, 7 kg Mg and 21 kg S per 1 ha was applied into the soil. Additionally, 72 kg·ha −1 N in the form of ammonium nitrate and urea solution (AHL) was used. Nitrogen in the form of AHL in the dose of 65 kg·ha −1 N was applied before the 2nd swath, and 36 kg·ha −1 N, also in the form of AHL, before the third swath.
The three to five swaths were collected in the vegetation seasons. The meadow sward of the first swath was harvested at the stage of booting/inflorescence emergence (beginning of heading) of the dominant species, and subsequent swaths at intervals from four to seven weeks also at the stage of booting/inflorescence emergence (beginning of heading). The biomass collected from the analyzed grasslands was used for hay silage. Detailed research included: floristic composition of meadow sward, yields of fresh and dry matter (DM) Agriculture 2021, 11, 537 6 of 20 and content of organic components (crude protein, crude fiber, water-soluble sugars) and the energy value-NEL (net energy lactation). The energy value was made according to method of Pries et al. [56]. The content of protein and soluble sugars was determined by the NIRS method [PN-EN ISO 12099. 2013]. Samples of plant material were taken from each plot of 1 m 2 . The floristic composition of the sward was determined using the botanicalweighted method [57], and the study gives the floristic composition of the first swath (the most representative for each year of study). Chemical analyses in cooperation with the National Research Institute for Agriculture and Fisheries of Mecklenburg-Vorpommern (Landesforschungsanstalt für Landwirtschaft und Fischerei MV) in Dummerstorf were carried out in the accredited laboratory of VDLUFA Rostock.  1 The percentage share of a given species in the mixture were calculated in relation to the seeding of this species in a pure sowing.

Statistical Analysis
The results of the study showing the dry matter yield development were statistically analyzed using the analysis of variance (ANOVA) procedure and the differences were tested with the Tukey test at the significance level p ≤ 0.05. Multivariate analysis was performed by applying principal component analysis (PCA). PCA transforms the data to a new coordinate system, retaining most of the information (the greatest variance by scalar projection of the data comes to lie on the first coordinate, the second greatest variance on the second coordinate-the so-called principal components). The analysis of the influence of mixtures with different floristic composition on the yield quality of meadow sward was also carried out. In order to determine the relation between mixtures and quality of meadow sward (content of crude protein, water-soluble carbohydrates, fibre and obtained dry matter), the results obtained were subjected to comparative analysis. The obtained results were subjected to agglomerative cluster analysis and classified into groups in a hierarchical arrangement by Ward's method. The method uses analysis of variance to estimate the distance between clusters [58]. The data were auto-scaled during pre-processing. All statistical analyses were performed using Statistica 12.5 (StatSoft Polska, Cracow, Poland).

Floristic Composition of Meadow Sward
The floristic composition of meadow sward in 2009, 2012 and 2013 after grassland renewal coincided with the participation of individual species in mixtures (Tables 4-6). * Explanations: objects identical with mixtures, whose composition is given in Table 3. Table 5. * Explanations: objects identical with mixtures, whose composition is given in Table 3.
Agriculture 2021, 11, 537 8 of 20 Table 6. Floristic composition of meadow sward (%) of experiment III from first cut in the years of research (2013-2018). * Explanations: objects identical with mixtures, whose composition is given in Table 3.

Object * Species
The paper presents results concerning floristic composition only from the first swath, because in the remaining swaths they were similar. A mild winter with a period of a short strong frost and surface flooding in the spring of 2010-2011 caused Lolium perenne to decline as a percentage of the floristic composition (Table 4).
A similar arrangement of results concerned all the evaluated mixtures, of which the most stable floristic composition was noted in the case of multi-species mixtures with a low proportion of Lolium perenne, i.e., mixtures from 2 to 5. Grass species introduced as components of the aforementioned mixtures showed high resistance to the existing habitat conditions and stability in the floristic composition in particular years (Table 4).
In the years of more stable weather conditions (2012 and 2013), the composition of mixtures tested in the second experiment proved to be more stable and close to the assumed sowing standard (Table 5).
In the third experiment, which lasted much longer than the second experiment, with a diverse set of weather conditions (amount and distribution of precipitation, very low temperatures in spring 2016) the floristic composition of the sward was stable in the first three years of the study. On the other hand, in the meadow sward of the first swath of 2016, freezing of plants, especially Lolium perenne and partly also Festulolium braunii, was observed, due to short-lived very low temperatures that occurred in early spring. This was not observed in Festuca arundinacea and Phleum pratense, which was reflected in the appearance of meadow sward on individual plots and its floristic composition (Table 6). Higher resistance to low temperatures of Festulolium braunii than Lolium multiflorum but lower than Festuca pratensis is indicated by the study of Šimkūnas et al. [60].
The process of sward regeneration with the participation of Lolium perenne and Festulolium braunii plants lasted until mid-June, because the floristic composition found during the harvest of the second swath (9 June 2016) was repeated in subsequent swaths. The results of all experiments showed that Festulolium braunii plants have a high stability of in sward and a lower response to unfavorable weather conditions compared to Lolium perenne and are slightly inferior to species such as Festuca arundinacea and Phleum pratense, which are reported in the literature as persistent species and well-developing in terms of habitat on organic soils [12,33].
PCA analysis showed that abundance in the Festulolium braunii and Lolium perenne sward depended on precipitation in February, March, April, May and June, during the growing season and throughout the year, as well as on temperature in March, April, July and August. The presented climatic conditions in the studied decade had a different effect on the abundance in the sward of Festulolium braunii and Lolium perenne (Figure 2). The PCA analysis should be treated with caution because it did not consider short winter and early spring frosts and surface water flooding, which affected Festulolium braunii and Lolium perenne cover. Nevertheless, this analysis and the results of Fb and Lp coverage obtained clearly indicate that Festulolium braunii is more durable in the sward than Lolium perenne under varying weather conditions. The high persistence of Festulolium braunii in the habitat even under unfavorable weather conditions is due to its well-developed root system, which it inherited from meadow fescue [36,41,42,55,62,63].
Lolim perenne is a very valuable grass of high fodder value willingly eaten by cattle. It is the main component of grassland sward in Europe [64]. This grass is durable and expansive but not very tolerant of adverse environmental conditions [37]. Kulik and Baryła [65], sowing a mixture of composition: Lolium perenne-35%, Trifolium repens-35%, Dactylis glomerata-10% and Phleum pratense-20% on organic soil, after previously applying Roundup herbicide and biting and rolling, found high persistence of Lolium perenne in pasture sward. After 12 years, the share of this species in the sward averaged 19.9% in the first regrowth and 22.0% in the third regrowth. These authors found large changes in the share of Lolium perenne in particular years, which was related to habitat conditions, especially water and thermal conditions. They found the loss of perennial ryegrass in frosty winters and its regeneration in the years when it increased its share in pasture sward. In general, during 12 years with favorable weather conditions, the fluctuations of Lolium perenne share in the pasture sward ranged from 7.3% to 63.0%. Such an arrangement of results is confirmed by our study, in which in conditions of low temperatures during winter and excess water in spring, there was a significant decrease in the share of Lolium perenne. The fast regeneration of Lolium perenne, as indicated by the quoted authors, was not confirmed in our study, as the lower share of this species found in 2010 was main- The high persistence of Festulolium braunii in the habitat even under unfavorable weather conditions is due to its well-developed root system, which it inherited from meadow fescue [36,41,42,55,62,63].
Lolim perenne is a very valuable grass of high fodder value willingly eaten by cattle. It is the main component of grassland sward in Europe [64]. This grass is durable and expansive but not very tolerant of adverse environmental conditions [37]. Kulik and Baryła [65], sowing a mixture of composition: Lolium perenne-35%, Trifolium repens-35%, Dactylis glomerata-10% and Phleum pratense-20% on organic soil, after previously applying Roundup herbicide and biting and rolling, found high persistence of Lolium perenne in pasture sward. After 12 years, the share of this species in the sward averaged 19.9% in the first regrowth and 22.0% in the third regrowth. These authors found large changes in the share of Lolium perenne in particular years, which was related to habitat conditions, especially water and thermal conditions. They found the loss of perennial ryegrass in frosty winters and its regeneration in the years when it increased its share in pasture sward. In general, during 12 years with favorable weather conditions, the fluctuations of Lolium perenne share in the pasture sward ranged from 7.3% to 63.0%.
Such an arrangement of results is confirmed by our study, in which in conditions of low temperatures during winter and excess water in spring, there was a significant decrease in the share of Lolium perenne. The fast regeneration of Lolium perenne, as indicated by the quoted authors, was not confirmed in our study, as the lower share of this species found in 2010 was maintained in the next year 2011. The high expansiveness of Poa pratensis in the period less favorable for Lolium perenne, which was indicated in peat-muck soils Kamiński [33], Baryła and Drozd [66] and Kulik and Baryła [65] was confirmed in our study. High prevalence of Poa pratensis on organic and organic-mineral soils of Western Pomerania in Poland was found by Czyż et al. [67,68].

Dry Matter Yield
Biomass obtained from objects sown with particular mixtures with different share of Festulolium braunii in the sward was characterized by a similar dry matter content, therefore in this study it was limited only to dry matter yields (Tables 7 and 8). In the first experiment carried out in the years 2009-2011, the highest dry matter yield was obtained on object 5 (13.85 t·ha −1 average from years), where the sward was a multi-species mixture with following composition: Festulolium braunii (39.5-29.9%), Lolium perenne, Poa pratensis, Dactylis glomerata and Phleum pratense. The yields obtained were higher than the other mixtures with a similar share of this species in mixtures 4 and 6 by 9.6% on average and with a higher share of Festulolium braunii in the sward in mixtures 1-3 by 12.3% on average ( Table 6).  Average results from the years of the study indicate that the sward of plot 5, where the mixture of the following composition was sown: Festulolium braunii-21.0%, Lolium perenne-29.0%, Poa pratensis-11.0%, Phleum pratense-18.0%, Dactylis glomerata-21.0% was characterized by the highest production potential, even when Lolium perenne almost completely fell out of the sward in the second year the study. It is noteworthy that the same mixtures, despite a significant fall out of Lolium perenne from the sward in 2010, in the third year of the study, yielded 42.3% higher than in 2009 and 60.5% higher than in 2010 (Table 7). This proves that the species used for mixtures including Festulolium braunii, apart from Lolium perenne, survived the excessive humidity of the habitat well (in winter and early spring 2010) and regenerated the sward, causing high yielding. The lowest yields were obtained from object 2, where the following species were used for regeneration: Festulolium braunii (43%), Poa pratensis (29%) and Lolium perenne (28%). The annual yield of biomass, obtained from grassland, is a component of yields from individual swaths.
The dry matter yields of mixtures in the second experiment were on average higher than those obtained in the first two years of use in the first experiment, but lower than the average yields from the third year by 6.7% (Table 7). In this experiment, the mixtures studied, regardless of the year of the study, yielded at a similar level with respect to the object, on which Festulolium braunii was sown in the greatest amount (50%), the yield of the remaining mixtures was higher than the average of 2.1% to 8.0%. In this experiment, also high yields of dry matter were obtained from an object sown with a multi-species mixture of Festulolium braunii-30%, Lolium perenne-20%, Poa pratensis-10% and Dactylis glomerata-40%.
The results of the dry matter yield obtained in the third experiment (Table 8) prove that under the tested habitat conditions, higher yields are obtained when mixtures with a richer species composition-mixture 3-are used to sow grassland, compared to two-component mixtures of Festulolium braunii and Lolium perenne (on average from the years of the study) by 10.8% (for a mixture with composition: 34 + 66%) and by 9.1% for the mixture with 50% share of the two species in sowing. The results from the six years of the study indicate that using short-lasting species (Lolium perenne and Festulolium braunii) in large quantities in grassland mixtures contributes to an increase in dry matter yields up to four years, while in subsequent years to a decrease in average yields by 34.1%-in the fifth and by 35.9% in the sixth year of the study (Table 8).
It follows from our own long-term studies that Festulolium braunii tolerates varied atmospheric conditions very well during the vegetation period and ensures stable sward yield in mixtures. Lolium perenne, on the other hand, under unfavorable weather conditions decreases its share in the sward, thus decreasing the harvested yield. PCA analysis (Figure 3) showed that the yield of sward dry matter depended most strongly on the share of Lolium perenne. Its place in the studied sward is largely taken by Festulolium braunii, which stabilizes yield but does not affect its growth.
Agriculture 2021, 11, x FOR PEER REVIEW 13 of 21 yield in mixtures. Lolium perenne, on the other hand, under unfavorable weather conditions decreases its share in the sward, thus decreasing the harvested yield. PCA analysis (Figure 3) showed that the yield of sward dry matter depended most strongly on the share of Lolium perenne. Its place in the studied sward is largely taken by Festulolium braunii, which stabilizes yield but does not affect its growth.  Ward's analysis grouped the objects (grass mixtures) according to similar meadow sward yield quality. The study considered a split with a bond distance of 4, yielding 4 aggregates of grass mixtures (Figure 4). The extreme groups include grass mixtures in which: (1) the proportion of Lolium perenne decreased greatly and that of Festulolium braunii increased; and (2) the proportion of Lolium prenne and Festulolium braunii did not change much. Such grouping of investigated mixtures indicates that quantitative increase in Festulolium braunii and decrease in Lolium prenne influences yield productivity and quality. The decrease in the proportion of Lolium prenne in the meadow sward largely compensates for the increase in the proportion of Festulolium braunii (stabilizing productivity and yield quality). The introduction of Festulolium braunii to the sward in progressing climatic changes is a good solution to maintain high and good quality sward yields. The results of research on cultivars of this hybrid indicate that dry matter yields are highfrom about 6 t/ha DM in the absence of mineral fertilisation to 18.13 t/ha DM with adequate mineral fertilisation [38,44,[69][70][71][72]. This species shows a favorable response to nitrogen fertilisation [73].
Gutmane and Adamovich [69], Grønbaek [70] and Østrem, et al. [38] indicate that Festulolium braunii hybrids yield better than Lolium perenne. Ward's analysis grouped the objects (grass mixtures) according to similar meadow sward yield quality. The study considered a split with a bond distance of 4, yielding 4 aggregates of grass mixtures (Figure 4). The extreme groups include grass mixtures in which: (1) the proportion of Lolium perenne decreased greatly and that of Festulolium braunii increased; and (2) the proportion of Lolium prenne and Festulolium braunii did not change much. Such grouping of investigated mixtures indicates that quantitative increase in Festulolium braunii and decrease in Lolium prenne influences yield productivity and quality. The decrease in the proportion of Lolium prenne in the meadow sward largely compensates for the increase in the proportion of Festulolium braunii (stabilizing productivity and yield quality). The introduction of Festulolium braunii to the sward in progressing climatic changes is a good solution to maintain high and good quality sward yields. The results of research on cultivars of this hybrid indicate that dry matter yields are high-from about 6 t/ha DM in the absence of mineral fertilisation to 18.13 t/ha DM with adequate mineral fertilisation [38,44,[69][70][71][72]. This species shows a favorable response to nitrogen fertilisation [73].

The Value of Food and Energy of Meadow Sward
The fodder obtained from a unit of area can be assessed by the quantity or quality of the harvest. According to Staniak and Harasim [49], and Olszewska [74], forage quality is influenced by many factors: sward species composition, plant development stage, soil moisture and nutrient abundance, and weather conditions.
The results of our study presented in Table 9 confirm the research Czyż et al. [75], which showed that the chemical composition, as well as the energy concentration, depends on the floristic composition of the sward. In our study, where the floristic composition of the sward (especially in the first years of the study) was similar to the share of individual species in the mixture used for grassland regeneration, the sward from the multi-component mixture of plot 6, where Festulolium braunii, Lolium perenne, Poa pratensis and Phleum pratense were found in the floristic composition, had the highest crude protein content. In general, the protein content in the research objects ranged from 124 to 158 g•kg −1 DM (Table 9).
PCA analysis showed that the crude protein content of forage harvested (under varying weather conditions), was due to the high proportion of Festulolium braunii in the sward.
According to Staniak [76], this hybrid under drought conditions does not respond by lowering the crude protein content of the sward. Moreover, under unfavorable environmental conditions, it favorably influences the development of other grass species more sensitive to the variability of weather conditions, which indirectly affects the protein content of the sward [76]. The crude protein content of Festulolium braunii has a wide range (from 66 g•kg −1 DM to 194 g•kg −1 DM) depending on environmental conditions and fertilisation [49,61,[70][71][72]76]. Despite the significant amount of crude protein in Festulolium braunii, similar to the content in grasses with high forage value, these amounts are generally insufficient for the nutritional requirements of cattle. The content of crude protein in the feed of dairy cattle should not fall below 150 g•kg −1 DM [72]. Therefore, this hybrid Gutmane and Adamovich [69], Grønbaek [70] and Østrem, et al. [38] indicate that Festulolium braunii hybrids yield better than Lolium perenne.

The Value of Food and Energy of Meadow Sward
The fodder obtained from a unit of area can be assessed by the quantity or quality of the harvest. According to Staniak and Harasim [49], and Olszewska [74], forage quality is influenced by many factors: sward species composition, plant development stage, soil moisture and nutrient abundance, and weather conditions.
The results of our study presented in Table 9 confirm the research Czyż et al. [75], which showed that the chemical composition, as well as the energy concentration, depends on the floristic composition of the sward. In our study, where the floristic composition of the sward (especially in the first years of the study) was similar to the share of individual species in the mixture used for grassland regeneration, the sward from the multi-component mixture of plot 6, where Festulolium braunii, Lolium perenne, Poa pratensis and Phleum pratense were found in the floristic composition, had the highest crude protein content. In general, the protein content in the research objects ranged from 124 to 158 g·kg −1 DM (Table 9).
PCA analysis showed that the crude protein content of forage harvested (under varying weather conditions), was due to the high proportion of Festulolium braunii in the sward.
According to Staniak [76], this hybrid under drought conditions does not respond by lowering the crude protein content of the sward. Moreover, under unfavorable environmental conditions, it favorably influences the development of other grass species more sensitive to the variability of weather conditions, which indirectly affects the protein content of the sward [76]. The crude protein content of Festulolium braunii has a wide range (from 66 g·kg −1 DM to 194 g·kg −1 DM) depending on environmental conditions and fertilisation [49,61,[70][71][72]76]. Despite the significant amount of crude protein in Festulolium braunii, similar to the content in grasses with high forage value, these amounts are generally insufficient for the nutritional requirements of cattle. The content of crude protein in the feed of dairy cattle should not fall below 150 g·kg −1 DM [72]. Therefore, this hybrid should occur with legumes and grasses with high protein content. On the other hand, Touno et al. [61] showed that despite lower crude protein in Festulolium braunii than in Phleum pratense L, milk yield in cows was higher in animals fed Festulolium braunii forage.
The crude fiber content ranged from 284 to 307 g·kg −1 DM. The upper value refers to objects 4 and 5, where the largest share of Dactylis glomerata was found in the sward. Table 9. The content of organic compounds (g·kg −1 DM) and the concentration of net energy NEL (net energy lactation, MJ·kg −1 DM) in the sward of the first swath. PCA analysis showed that the proportion of Festulolium braunii and Lolium perenne had no effect on crude fibre content in the sward. In contrast, the proportion of other grasses in the sward had a significant effect.

Years
Too high a fibre content worsens the digestibility of the forage. Smaller amounts of crude fibre between 211-243 g·kg −1 DM in the sward with Festulolium braunii were found by Staniak [76]. At the same time, the author showed that under drought conditions Festulolium braunii contained less crude fibre than under optimal moisture conditions. Touno et al. [61] found 293 g·kg −1 DM crude fibre in Festulolium braunii. The author indicated that this hybrid has significantly less fibre than Phleum pratense. Significant variations in crude fibre content in Festulolium braunii (from 179 to 320 g·kg −1 DM under optimal moisture conditions and from 206 to 241 g·kg −1 s.m under drought conditions were found by Staniak and Harasim [49]. In terms of soluble sugars (108 and 104 g·kg −1 DM), the sward from objects 1 and 2 in the floristic composition, of which only two species of Festulolium braunii and Lolium perenne were found, was outstanding. This is in consistent with opinion of Ciepiela [77,78], Kozłowski et al. [79], Downing and Gamroth [80], who state that Lolium perenne and Festulolium braunii have a high soluble sugar content among other species. According to Ciepiela [78] Festulolium braunii has a low tendency to accumulate unstructured carbohydrates. A similar opinion of Lolium perenne was expressed by Kozłowski et al. [79] and Piecuch et al. [81].
PCA analysis showed that only the proportion of Festulolium braunii positively shaped the content of water-soluble carbohydrates in the dry matter of the studied sward.
Studies by Gronbak [70], Staniak and Harasim [49], Staniak [76] showed that Festulolium braunii is characterized by a high variation in water-soluble carbohydrate content most often from about 60 to about 100 g·kg −1 DM, while not exceeding 240 g·kg −1 DM. No clear effect of drought on carbohydrate content in the hybrid was found [49,76]. The high carbohydrate content of Festulolium braunii predisposes this species to form mixtures with high-protein legumes, e.g., limpet, alfalfa [74,76,82]. Forages with a high proportion of water-soluble carbohydrates improve protein digestibility and reduce nitrogen losses, they also have good digestibility, which results in good development of cattle [83,84]. In addition, cattle prefer grasses with a high proportion of carbohydrates [84].
In assessing forage quality, the ratio of water-soluble carbohydrates to crude protein is important, indicating protein availability to cattle [85]. A ratio in the range of 0.8-1.5 is beneficial for cattle (good nitrogen utilisation), but should not be less than 0.4 [82,84,85]. The tested mixtures with Festulolium braunii had sugar-protein ratios > 0.4. Equally favorable sugar-protein ratios in mixtures with Festulolium braunii (0.46) were obtained by Sosnowski [82]. On the other hand, Malinowska [71] found a clear effect of fertilisation on the sugar-protein ratio in Festulolium braunii (from 0.704 to 1.53). The ability of Festulolium braunii to accumulate sugars also plays an important role in its resistance to stress conditions, especially water stress [76].
The energy concentration of the sward from all plots was similar: from 6.0 to 6.3 MJ·kg −1 NEL (Table 9). Assessing the fodder value of the meadow sward on the basis of the net energy concentration, it was found that it was at the level recommended for fodder (6 MJ·kg −1 DM), which ensures the proper development of farm animals [86].
PCA analysis showed that the net energy concentration of the harvested sward depended positively to a small extent on the share of Festulolium braunii and other grasses, and negatively on the share of Lolium perenne.
Studies by Gronbaek [70] showed that different cultivars of Festulolium braunii were characterised by energy concentrations ranging from 6.02 to 6.16 MJ·kg −1 NEL DM and Lolium perenne 6.43 MJ·kg −1 NEL DM.
In the second year of the study (2010), as a result of very low temperatures in winter and spring floods, the beginning of vegetation was significantly delayed and significant changes in the floristic composition were found: these concerned mainly Lolium perenne, the share of which was very much reduced and was replaced by Dactylis glomerata, Poa pratensis and Phleum pratense and, to a lesser extent, Festulolium braunii (Table 4).
There was also a delay in harvesting the first swath (12 June 2010). Harvesting was carried out in the phase of the dominant species earing. The consequence of the delayed harvest was higher fiber content and lower protein and sugars (Table 9). Jankowska et al. [87] conducting research on a three-cut meadow with a grass community dominated by Festuca pratensis, Dactylis glomerata and Poa pratensis, found 157 g·kg −1 DM crude protein, 75.5 g·kg −1 DM soluble sugars and 260-290 g·kg −1 DM of crude fiber in the sward from the first swath. Comparing the results obtained in our study with the data of Jankowska et al. [87], it should be stated that in the first year of the study (2009), in which four swaths were collected, the protein and fiber content in the first swath was consistent with the literature data, while the content of soluble sugars was twice as high. The literature underlines that Festulolium braunii with legumes is a very good feed for cattle [52,76,82].
Biomass production in particular regrowth (swaths) took place under different habitat conditions (groundwater level, air temperature, sunshine) and, therefore, not only were the values of particular parameters different, but also the sward quality was differentiated. The results of our study ( Table 9) show, that in the years in which four or five swaths with the best fodder value were collected, the share of Festulolium braunii and Lolium perenne in the floristic composition of individual plots was significant. The highest content of crude protein, soluble sugars and net energy concentration (NEL) and the lowest content of crude fiber were found. Gos and Kitczak [88], conducting research on grasslands located on organic soil, found that harvesting four swaths, biomass was obtained with good parameters, especially of the formation of protein and fiber. According to our assessment of the fodder value of biomass from individual swaths, the best values of analyzed parameters were obtained in the first swath. The greatest differences between swards from particular swaths concerned sugar content. Swaths harvested in summer were characterized by a much lower concentration of soluble sugars than swaths harvested in spring and autumn. The clear decrease in the concentration of unstructured carbohydrates in the summer can be explained by the increased respiration of the plants under high temperature conditions, and mainly sugars are used in this process [89,90]. Similar results were obtained Kozłowski et al. [79], Goliński and Kozłowski [91], Downing and Gamroth [80] and Ciepiela [78].

Conclusions
1. Festulolium braunii tolerates varied and unfavorable weather conditions (frosts during snowless winters, spring frosts and waterlogging, and droughts) very well and provides a stable good quality sward yield. Lolium perenne, on the other hand, decreases its share in the sward under unfavorable weather conditions. 2. A greater share of Festulolium braunii in the sward affected favorably the content of carbohydrates and protein in the sward, and to a small extent the energy concentration. On the other hand, there was no contribution of Festulolium braunii and Lolium perenne on the crude fibre content in the sward.
3. The proportion of Festulolium braunii and Lolium perenne in the meadow sward affects yield productivity and quality.
4. All the results obtained indicate that, in the analysed habitat, in order to ensure stability of yielding and obtaining fodder of good quality indices, under specific weather conditions of a changing climate, it is justified to apply Festulolium braunii to grass mixtures for grassland regeneration.

Conflicts of Interest:
The authors declare that they have no known competing financial interest or personal relationships that could have appeared to influence the work reported in this paper.

Compliance with Ethics Requirements:
This article does not contain any studies with human or animal subjects.