Floral Composition and Productivity of Leys and Permanent Grasslands in Baltic Livestock Farms

Abstract

Agricultural reforms, land consolidation, and the abandonment of livestock farming effects grassland ecosystems worldwide. Utilising data from four medium-sized livestock farms across different regions in Lithuania, we assess floristic composition, productivity, and grass quality in both permanent grasslands and leys. Our findings reveal significant differences in flora diversity, with 120 species identified in permanent grasslands compared to only 20 in leys. Additionally, dry matter yield was notably higher in leys (13.97 t ha⁻¹) than in permanent grasslands (5.66 t ha⁻¹), underscoring the productivity potential of leys. The crude protein levels remained stable across both types, but leys demonstrated significantly lower neutral detergent fibre content, indicating better forage quality. However, the high biodiversity of permanent grasslands supports ecosystem services.

1. Introduction

The issues of grasslands decline and biodiversity conservation in Europe remain highly relevant today. Since 1980, 70,456 publications have explored ecosystem services, with 696 showing that preventing grassland conversion supports multiple services and that higher species diversity boosts multifunctionality, with few trade-offs [1]. This issue is also significant in Lithuania. In recent years, the threshold of a 5% decrease in permanent grasslands in Lithuania has been surpassed, necessitating their restoration. Historically, the area of these grasslands in Lithuania remained relatively stable [2]. However, significant structural changes in Lithuanian agriculture began approximately 20 years ago, following agricultural reforms and the implementation of the “Early Retirement from Commercial Agricultural Production” measure [3]. This program led to the cessation of agricultural activities in many small farms. As new landowners consolidated these farms and abandoned livestock farming, the crop structure began to shift. With farm consolidation and the widespread abandonment of livestock farming, there was a notable decrease in the number of animals. Between 2005 and 2023, the number of registered cattle decreased from 968,854 to 641,066, a decline of 38.8%. Similarly, the number of dairy cows decreased from 455,828 to 222,954, a decline of 51.1%. In the latter half of 2022 alone, the number of cattle decreased by 14,753, including 6965 dairy cows [4].

All these factors have led to rapid changes in the use of grasslands. Less fertile grasslands have been ploughed, while others have been abandoned or afforested. Permanent grasslands, which are older, long-established areas with diverse plant species, have seen a marked reduction in area; from 665,802.23 ha in 2015, their extent decreased to 531,885.87 ha by 2023. These grasslands differ from leys, which are temporary grasslands typically maintained for five years or less and are part of crop rotation systems. While permanent grasslands have continued to decline, the area of leys has stabilised since 2017 and even shows a slight tendency to increase [5].

The grassland ecosystems of Lithuania, particularly those bordering forests, wetlands, or river valleys, are notable for their rich plant species diversity, with up to 500 plant species recorded in Lithuanian grasslands [6]. Similar to other countries at comparable geographical latitudes, grassland ecosystems in Lithuania can persist only through activities such as grazing, mowing, or flooding in river floodplains [7].

Farmers who have abandoned livestock farming in favour of growing cereals and other crops have had to alter their use of grasslands. Some permanent grasslands were abandoned, while, for others, the grass was mowed and left to decompose. This practice has led to increased eutrophication of the grasslands and the formation of nitrophilous plant communities, a conclusion supported by studies in Lithuania, Latvia, and other countries [8]. In soils with a higher nutrient content, plant species diversity decreases [9]. Furthermore, botanical species diversity recovers more rapidly in extensively managed grasslands than under intensive farming conditions [10]. Biodiversity tends to decrease with the intensification of agricultural activities in agrarian territories [11,12].

This research was designed to assess the current condition of Lithuanian grasslands, with a particular focus on floristic composition in permanent grasslands. The floristic composition in these ecosystems is influenced by multiple factors, including grassland age, soil texture, the seed bank, and various ecological conditions. To understand how recent agricultural changes have affected these parameters, we selected four medium-sized livestock farms from different regions of Lithuania, each containing both leys and permanent grasslands. The primary objectives of this research were to evaluate the impact of recent agricultural transformations on floristic composition, productivity, and forage quality in permanent grasslands and to identify key differences between leys and permanent grasslands. By examining these dynamics, the study seeks to provide insights into the effects of land use shifts on grassland ecosystems and inform strategies for their sustainable management.

2. Materials and Methods

The study was caried out during 2019–2020 on four livestock farms located in different regions of Lithuania: Lazdijai District (54.150047, 23.596925), Kėdainiai District (55.392889, 24.028194), Šilalė District (55.533385, 21.89682), and Zarasai District (55.899338, 26.027993) (Figure 1). These farms encompassed grasslands of varying ages, including leys (up to 5 years old) and permanent grasslands (over 25 years old). In the ley grasslands, specific sowing mixtures were used, varying by district, to optimise productivity and herbage quality (

Table A1. The sowing mixtures in the ley grasslands.

Species	Lazdijai	Kėdainiai	Šilutė	Zarasai
Lolium perenne L.	20	10	20	25
Phleum pratense L.	-	-	20	5
Festuca pratensis Huds.	20	15	20	10
× Festulolium spp.	-	15	15	-
Trifolium repens L.	15	15	10	5
Trifolium pratense L.	20	25	10	20
Poa pratensis L.	5	3	5	5
Medicago sativa L.	15	13	-	10
Lolium multiflorum var. italicum (Husn.) Beck.	-	4	-	-
Medicago lupulina L.	-	-	-	5
Lotus corniculatus L.	-	-	-	5
Festuca rubra L.	5	-	-	10

). These mixtures were selected and implemented independently by the farmers, with no researcher involvement in determining the trajectory or dynamics of the sown leys. The dominant species across the leys included Lolium perenne L., Festuca pratensis Huds., Trifolium repens L., and Trifolium pratense L., with some variations in composition by region. All grasslands were managed with a mixed-use approach, involving haying for the first cut and grazing thereafter.

The analysis was conducted in selected plots –1 m² of each. The location of the plots was chosen randomly, and the number of plots depended on the size and composition of the grassland. Square plots were used in areas with uniform grass cover, while rectangular (elongated) plots were used in areas with sparse vegetation [13]. The samples for the determination of the grassland productivity; herbage feed value; and functional groups (grasses, legumes, herbs, and sedges) were taken from 7 to 16 plots in leys and from 11 to 18 plots in the permanent grasslands when the main legumes/grasses started flowering/heading (end of May/mid–June).

Table 1. Spatial allocation of sampling units and grassland area across grassland types and districts.

	Kėdainiai Distr.		Lazdijai Distr.		Šilalės Distr.		Zarasai Distr.
Type of grassland	ley	perennial	ley	perennial	ley	perennial	ley	perennial
Plots number	16	18	7	11	6	16	14	14
Area of grassland, ha	1.5	2.0	1.29	2.75	1.74	5.95	6.65	2.6

provides a comprehensive summary of the sampling distribution across grassland types and regions, detailing the number of plots and total grassland area (ha) within each district.

The same plots were used to identify the floristic composition. The sward was cut in an area of 1 m², leaving a height of stubble approximately 5 cm. For determining the functional groups, the sample was separated according to the groups: grasses, legumes, herbs, and sedges. Each group was weighed separately. Samples (0.5 kg) for dry matter yield were dried to constant weight at 105 °C in a ventilated oven. Further, the samples were weighed, and the dry matter yield in kg m⁻² was calculated [13].

In Lithuania, the spontaneous flora of herbaceous plant species has been documented to include approximately 500 species across all grassland types [6]. To evaluate the floristic composition of the grasslands, all plant species were first catalogued during this study. The species in permanent grasslands were further categorised into three groups: (1) common and very common, (2) moderately common, and (3) quite rare and rare. Meantime, Braun-Blanquet scale (1964) was used to estimate the cover abundance of each species as a percentage [14].

The Jaccard similarity index (J (a, b)) was used to determine the floristic similarity of the investigated permanent grasslands:

$$\mathrm{J}\left(\mathrm{a},\mathrm{b}\right)={\displaystyle \frac{\mathrm{c}}{\mathrm{a}+\mathrm{b}-2}}\times 100\mathrm{\%}$$

where:

c is the number of species common to both grasslands,

a is the total number of species in the first grasslands,

b is the total number of species in the second grasslands.

The herbage feed value was analysed by collecting fresh biomass samples (250 g of each) during the flowering/heading stage of the plants before the first cut. The samples were fixed for 20 min at 105 °C, dried to constant weight, and then milled. Crude protein (CP) and neutral detergent fibre (NDF) concentrations were measured using a near-infrared reflectance spectrometer (NIRS-6500, FOSS NIRSystems, Inc.: Silver Spring, MD, USA) [15].

2.1. Meteorological Conditions

Meteorological conditions, including temperature and precipitation, are presented in Figure A1 (data from the Lithuanian Hydrometeorological Service) [16]. The winter of 2019 was notably mild, with temperatures above the seasonal averages. During the subsequent growing season, periods of dryness alternated with wetter intervals, creating generally favourable conditions for plant growth throughout most of the vegetation period. Autumn was marked by variable moisture levels, transitioning from dry spells to optimal humidity, followed by increased precipitation that restored favourable soil moisture conditions. This progression of weather patterns contributed to optimal plant preparation for the onset of winter.

In 2020, both winter and autumn were the warmest seasons ever recorded in Lithuania’s meteorological history. A notable characteristic of 2020 was the extremely low number of days with snow cover and the absence of cold days, attributed to the exceptionally warm winter. The growing season began, on average, four days earlier than usual. Optimal growing conditions were observed in June and July. However, drought conditions, recognised as a dangerous meteorological phenomenon, were first recorded in specific regions, such as Kėdainiai District, on August 25 and continued to spread throughout September. By early October, most parts of the country experienced dry and drought conditions, as indicated by the hydrothermal coefficient values.

2.2. Statistics

The statistical analysis was carried out in the open-source R statistical environment version 4.3.1. R package ‘rstatix’ was used to calculate the basic statistics. Analysis of variance (ANOVA) and post hoc Tukey’s honest significance test (using the ‘agricolae’ package) were conducted to analyse the differences in dry matter yield (DMY) and quality traits between leys and permanent grasslands across two years, resulting in four groups. Additionally, DMY differences in the leys were analysed across four regions over two years, resulting in eight groups [17,18,19].

3. Results and Discussion

3.1. Flora Composition

During the study, 120 grass species were identified across the permanent grasslands in the four surveyed farms, with the number of species per grassland ranging from 49 to 89 (

Table A2. Floristic composition of permanent grasslands (+ indicates that the respective species was found at the research site. − indicates that the respective species was not found at the research site).

No.	Species	Kėdainiai Distr.	Zarasai Distr.	Šilalė Distr.	Lazdijai Distr.
1	Achillea millefolium L.	+	+	+	+
2	Alchemilla vulgaris L.	+	+	+	+
3	Anthoxanthum odoratum L.	+	+	+	+
4	Centaurea jacea L	+	+	+	+
5	Cerastium holosteoides Fr.	+	+	+	+
6	Deschampsia cespitosa (L.) P. Beauv.	+	+	+	+
7	Galium mollugo L.	+	+	+	+
8	Lathyrus pratensis L.	+	+	+	+
9	Leontodon hispidus L.	+	+	+	+
10	Lotus corniculatus L	+	+	+	+
11	Luzula campestris (L.) DC	+	+	+	+
12	Plantago lanceolata L.	+	+	+	+
13	Poa pratensis L.	+	+	+	+
14	Ranunculus acris L.	+	+	+	+
15	Rumex acetosa L.	+	+	+	+
16	Veronica chamaedrys L.	+	+	+	+
17	Vicia cracca L.	+	+	+	+
18	Agrimonia eupatoria L.	+	+	+	+
19	Carex hirta L	+	+	+	+
20	Dactylis glomerata L.	+	+	+	+
21	Elytrigia repens (L.) Nevski	+	+	+	+
22	Festuca pratensis Huds.	+	+	+	+
23	Festuca rubra L.	+	+	+	+
24	Stellaria graminea L.	+	+	+	+
25	Taraxacum officinale F. H. Wigg.	+	+	+	+
26	Trifolium pratense L.	+	+	+	+
27	Trifolium repens L.	+	+	+	+
28	Cirsium arvense (L.) Scop.	−	+	+	+
29	Holcus lanatus L.	+	−	+	+
30	Hypericum perforatum L.	−	+	+	+
31	Leucanthemum vulgare Lam.	+	+	−	+
32	Phleum pratense L.	+	+	+	−
33	Pilosella officinarum F. W. Schultz et Sch. Bip.	+	−	+	+
34	Polygala comosa Schkuhr	+	−	+	+
35	Potentilla anserina L.	+	−	+	+
36	Ranunculus repens L.	+	+	+	−
347	Rhinanthus minor L.	+	−	+	+
38	Artemisia vulgaris L.	−	−	+	+
39	Anthriscus sylvestris (L.) Hoffm.	+	+	−	−
40	Barbarea vulgaris W.T. Aiton	−	−	+	+
41	Bromus hordaceus L	−	−	+	+
42	Carlina vulgaris L	−	−	+	+
43	Carum carvi L.	−	−	+	+
44	Cichorium intybus L.	−	−	+	+
45	Cynosurus cristatus L.	+	+	−	−
46	Daucus carota L.	−	−	+	+
47	Equisetum arvense L.	+	+	−	−
48	Filipendula ulmaria (L.) Maxim.	+	+	−	−
49	Hypochaeris radicata L.	+	+	−	−
50	Knautia arvensis (L.) Coult.	+	+	−	−
51	Medicago falcata L.	−	−	+	+
52	Medicago lupulina L.	−	−	+	+
53	Plantago major L.	−	+	+	−
54	Prunella vulgaris L.	+	+	−	−
55	Agrostis capillaris L.	+	−	−	−
56	Artemisia campestris L.	+	−	−	−
57	Briza media L.	+	−	−	−
58	Calamagrostis epigejos (L.) Roth	+	−	−	−
59	Campanula glomerata L.	+	−	−	−
60	Cardamine pratensis L.	+	−	−	−
61	Carex disticha Huds.	+	−	−	−
62	Carex flacca Shreb.	+	−	−	−
63	Carex nigra (L.) Reichard	+	−	−	−
64	Carex panicea L.	+	−	−	−
65	Cerastium arvense L.	+	−	−	−
66	Dactylorhiza incarnata (L.) Soó	+	−	−	−
67	Dactylorhiza longifolia Aver.	+	−	−	−
68	Equisetum palustre L.	+	−	−	−
69	Festuca trachyphylla (Hack.) Krajina	+	−	−	−
70	Filipendula vulgaris Moench.	+	−	−	−
71	Galium album Mill.	+	−	−	−
72	Galium boreale L	+	−	−	−
73	Galium verum L.	+	−	−	−
74	Geranium pratense L.	+	−	−	−
75	Geum rivale L.	+	−	−	−
76	Glechoma hederacea L.	+	−	−	−
77	Helictotrichon pubescens (Huds.) Pilg.	+	−	−	−
78	Heracleum sibiricum L.	+	−	−	−
79	Hylotelephium maximum (L.) Holub	+	−	−	−
80	Juncus compresus Jackq	+	−	−	−
81	Lysimachia nummularia L.	+	−	−	−
82	Phleum phleoides (L.) H. Karst.	+	−	−	−
83	Pimpinella saxifraga L.	+	−	−	−
84	Plantago media L.	+	−	−	−
85	Platanthera bifolia (L.) Rich.	+	−	−	−
86	Poa angustifolia L.	+	−	−	−
87	Ranunculus polyanthemos L.	+	−	−	−
88	Rhamnus catharticus L.	+	−	−	−
89	Rhinanthus angustifolius (Scop.) Pollich.	+	−	−	−
90	Rumex acetosella L.	+	−	−	−
91	Rumex thyrsiflorus Fingerh.	+	−	−	−
92	Rubus caesius L.	+	−	−	−
93	Saponaria officinalis L	+	−	−	−
94	Senecio jacobaea L.	+	−	−	−
95	Silene pratensis (Rafn) Godr.	+	−	−	−
96	Solidago virgaurea L.	+	−	−	−
97	Tanacetum vulgare L.	+	−	−	−
98	Thalictrum minus L.	+	−	−	−
99	Tragopogon orientalis L.	+	−	−	−
100	Tragopogon pratensis L.	+	−	−	−
101	Veronica longifolia L.	+	−	−	−
102	Agrostis gigantea Roth.	−	+	−	−
103	Campanula patula L.	−	+	−	−
104	Carex pallescens L.	−	+	−	−
105	Fragaria vesca L.	−	+	−	−
106	Lychnis flos-cuculi L.	−	+	−	−
107	Poa trivialis L.	−	+	−	−
108	Ranunculus auricomus L.	−	+	−	−
109	Rumex crispus L.	−	+	−	−
110	Trifolium dubium Sibth.	−	+	−	−
111	Trifolium medium L.	−	+	−	−
112	Rumex obtusifolius L.	−	−	+	−
113	Silene vulgaris (Moench) Garcke	−	−	+	−
114	Veronica serpyllifolia L.	−	−	+	−
115	Anthemis tinctoria L.	−	−	−	+
116	Arrhenatherum elatius (L.) P.Beauv. ex J. Presl et C.Presl.	−	−	−	+
117	Festuca gigantea (L.) Vill.	−	−	−	+
118	Medicago sativa	−	−	−	+
119	Onobrychis viciifolia Scop.	−	−	−	+
120	Ranunculus bulbosus L.	−	−	−	+

). Twenty-seven species were found in all surveyed grasslands. Poa pratensis L., Deschampsia cespitosa (L.) P. Beauv., Vicia cracca L., Lotus corniculatus L., Lathyrus pratensis L., Plantago lanceolata L., Veronica chamaedrys L., Achillea millefolium L., Dactylis glomerata L., Festuca rubra L., Festuca pratensis Huds., Elytrigia repens (L.) Nevski., Trifolium pratense L., Trifolium repens L., Taraxacum officinale F. H. Wigg., Carex hirta L., Stellaria graminea L., Agrimonia eupatoria L., Alchemilla vulgaris L., Anthoxanthum odoratum L., Centaurea jacea L., Cerastium holosteoides Fr., Galium mollugo L., Leontodon hispidus L., Luzula campestris (L.) DC, Ranunculus acris L., and Rumex acetosa L. Additionally, 10 species were found in three of the four surveyed farms: Phleum pratense L., Potentilla anserina L., Pilosella officinarum F.W. Schultz et Sch.Bip., Rhinanthus minor L., Polygala comosa Schkuhr, Hypericum perforatum L., Cirsium arvense (L.) Scop., Holcus lanatus L., Leucanthemum vulgare Lam., and Ranunculus repens L. These species are considered the most common in Lithuanian grasslands. In total, 37 species are classified as frequent and widely distributed in intensively used permanent grasslands.

In two out of the four surveyed locations, 17 species were categorised into the moderately common group. These moderately common species include Artemisia vulgaris L., Anthriscus sylvestris (L.) Hoffm., Barbarea vulgaris W.T. Aiton, Bromus hordaceus L., Carlina vulgaris L., Carum carvi L., Cichorium intybus L., Cynosurus cristatus L. Daucus carota L. Equisetum arvense L., Filipendula ulmaria (L.) Maxim., Hypochaeris radicata L., Knautia arvensis (L.) Coult., Medicago falcata L. Medicago lupulina L. Plantago major L., and Prunella vulgaris L. These species are common throughout Lithuania and widely distributed across the territory, but they are moderately prevalent in intensively used grasslands. Our finding aligns with similar studies in Central Europe by Klimek et al. (2007) and Wilson et al. (2012), who observed high species diversity in semi-natural grasslands, suggesting that permanent grasslands consistently support a rich diversity across regions [20,21]. Meanwhile, 66 species were found only in one of the surveyed farms. These species are not rare in Lithuania but are adapted to grow in specific conditions and are relatively rare in intensively used permanent grasslands. In contrast, only 20 species were identified in leys (

Table A3. Floristic composition of leys in research sites (+ indicates that the respective species was found at the research site. − indicates that the respective species was not found at the research site).

No.	Species	Kėdainiai Distr.	Zarasai Distr.	Šilalė Distr.	Lazdijai Distr.
1	Cirsium arvense (L.) Scop.	−	+	+	+
2	Dactylis glomerata L.	+	−	−	+
3	Festuca arundinacea Schreb.	+	−	−	−
4	Festuca pratensis Huds.	+	+	+	+
5	Festuca rubra L.	+	+	+	+
6	Lolium petrenne L.	+	+	+	+
7	Lotus corniculatus L	+	−	−	−
8	Medicago lupulina L.	+	−	+	−
9	Medicago sativa L.	+	+	−	+
10	Phleum pratense L.	+	+	+	−
11	Plantago major L.	−	+	+	−
12	Poa pratensis L.	+	+	+	+
13	Ranunculus repens L.	+	−	−	−
14	Rumex crispus L.	−	+	−	−
15	Rumex obtusifolius L.	−	−	+	−
16	Stellaria graminea L.	+	−	−	−
17	Taraxacum officinale F. H. Wigg.	+	+	+	+
18	Trifolium pratense L.	+	+	+	+
19	Trifolium repens L.	+	+	+	+
20	× Festulolium spp.	+	−	−	−

), a much lower number, which highlights the richness of permanent grasslands. This reduced diversity in leys is consistent with the findings by Pavlů et al. (2003), who reported significantly fewer species in managed leys compared to natural grasslands [22]. This disparity underscores the ecological value of permanent grasslands for maintaining biodiversity that intensively managed leys cannot support.

The flora of permanent grasslands in different locations varies considerably. Their coefficient of similarity ranges from 31.13% (Lazdijai vs. Kėdainiai) to 76.79% (Lazdijai vs. Šilalė). The results indicate that the grasslands in the Lazdijai and Šilalė Districts exhibited the greatest similarity of species. In contrast, the grasslands in the Kėdainiai District displayed the most distinct environmental characteristics among all the studied sites (

Table 2. Floristic similarity percent (%) in permanent grasslands across different regions of Lithuania.

	Zarasai	Šilalė	Lazdijai
Kėdainiai	36.27	32.69	31.13
Zarasai		47.76	42.86
Šilalė			76.79

). This uniqueness is primarily due to significant variations in terrain, soil composition, and hydrological regime associated with the Nevėžis River Valley. These environmental conditions foster a uniquely diverse floristic composition, further enhanced by the north–south species migration corridor along the river valley.

The floristic composition of leys mostly depends on the species of the sown mixture. In our studied livestock farms, forage grass mixtures were sourced from two breeding companies. Those forage grass mixtures consisted of three to nine components. During the study, it was found that leys in individual farms contained only 10–16 plant species. In specific study plots, only five to nine species per square meter were identified. Across four farms, only 20 herbaceous plant species were inventoried in leys. The predominant forage species included F. pratensis, T. repens, T. pratense, L. perenne, and P. pratense. Less common species were Medicago sativa L., M. lupulina, L. corniculatus, and × Festulolium spp.. Other species were classified as weeds. T. officinale and C. arvense were widespread in almost all the studied sites, while other species were sparse or isolated. In some fields, such as those in Šilalė, Rumex obtusifolius L. grew abundantly, whereas it was absent in the other grasslands. Thus, in terms of floristic composition, permanent grasslands and leys are incomparable. The number of species differed by nearly fivefold (20 vs. 120 species). Permanent grasslands were dominated by plants typical of natural grasslands, while the leys were predominantly composed of sown grasses and legumes, with a small proportion of weeds. This contrast between permanent grasslands and managed leys is consistent with studies by other authors, who noted that species richness in permanent grasslands is significantly higher than in leys, emphasising that species-rich grasslands provide a diverse habitat structure beneficial for ecosystem services and biodiversity conservation [22,23]. Therefore, from a biodiversity conservation perspective, permanent grasslands are incomparably more valuable.

It is important to note that, about 25 years ago, grasslands meeting the criteria for habitats of European importance began to be establish or had already been established in areas previously occupied by cultivated fields. Within these permanent grasslands, we identified habitats of European significance, including 6270 species-rich Agrostis grasslands (6270 Fennoscandian lowland species-rich) and 6510 lowland hay grasslands [24]. Such habitats have been highlighted in various studies, which emphasises the importance of species-rich grasslands in contributing to European biodiversity goals and their susceptibility to decline due to intensive agricultural practices [25,26]. The formation of other habitat types is impeded by specific agricultural practices.

The grasslands analysed were located over 100 kilometres apart each other, resulting in their exposure to distinct meteorological conditions. In addition to these climatic differences, other ecological factors may also have played a major role in shaping the floristic composition of the grasslands.

3.2. DMY Productivity in Leys and Grasslands

The dry matter yield (DMY) of permanent grasslands and leys over a two-year period from 2019 to 2020 is represented in Figure 2. The mean DMY for leys was significantly higher than for permanent grasslands, with values of 13.97 t ha⁻¹ and 5.66 t ha⁻¹, respectively. This indicates that, on average, leys produce nearly 2.5 times more dry matter than permanent grasslands, underscoring their higher productivity potential. Meanwhile, the variability of DMY among the leys suggests that factors such as management practices, environmental conditions, or species and genetic diversity within the leys group might significantly influence the yield outcomes [27]. Permanent grasslands, on the other hand, showed less variation in DMY, indicating more consistent productivity.

The ANOVA results indicated that the type of grassland was a significant factor affecting dry matter yield, demonstrating that leys statistically significantly (p < 0.0001) outperformed permanent grasslands in productivity in 2020. However, there was no statistically significant difference (p = 0.053), though a tendency suggested that leys outperformed permanent grasslands in terms of DMY in 2019. Neither the year of observation nor the interaction between year and grassland type was statistically significant (p = 0.171 and p = 0.211, respectively), indicating consistent yield differences were driven primarily by grassland type and remained consistent over the study period. The higher productivity of leys suggests they are more effective for maximising DMY. However, significant variations within leys highlight the need for optimised management practices and variety selection to achieve consistent high yields. The non-significant effects of year and year × type interactions imply that the annual external factors did not significantly alter the relative productivity of leys and permanent grasslands.

DMY varied between the two years of research. The results reveal that the yields in 2019 were more uniform across different locations, whereas, in 2020, the grasslands in Šilalė and Zarasai showed notable differences in yield compared to other locations (Figure 3). No statistically significant differences were identified in the studied areas in 2019. However, the lowest dry matter yield was documented in Lazdijai at 1.22 t ha⁻¹, whereas the highest yield was measured in Šilalė at 1.73 t ha⁻¹.

Meantime, in 2020, Lazdijai exhibited the lowest yield of 0.97 t ha⁻¹ in comparison to Zarasai and Šilalė, which had yields of 2.61 t ha⁻¹ and 2.69 t ha⁻¹, respectively. However, the yields of Zarasai and Šilalė were not statistically significantly different from each other. Additionally, the yield of dry matter did not show significant differences among the other research sites.

The composition and yield of grassland mixtures are influenced by species diversity, fertilisation, and harvest timing. Multi-species mixtures, particularly those that include legumes, tend to produce higher yields and better forage quality compared to monocultures [28,29]. However, while fertilisation can enhance yields, it may also lead to a reduction in species diversity [30]. Over time, the relative abundance of species in these mixtures shifts due to varying growth rates and environmental pressure [29,31].

The significance of seed mixture composition and the age of the leys has been highlighted as a crucial factor affecting dry matter yields, with older leys often showing reduced productivity compared to younger ones [32]. This underscores the importance of optimising species diversity and management practices to sustain high yields in leys. Overall, these findings suggest that leys, with appropriate management, offer greater potential for yield improvement and soil health compared to permanent grasslands.

Furthermore, separate research has emphasised the role of plant species diversity and the proportion of legumes in improving yields in leys [28,33,34]. Genetic factors that impact dry matter yield, especially in L. perenne, have also been explored, with Wilkins (2007) identifying key traits that influence the yield potential [35]. Our findings align with these studies, demonstrating that the dry matter yield (DMY) of leys was significantly higher than that of permanent grasslands, indicating their potential for increased productivity. However, the variability within leys suggests that management practices and environmental conditions significantly influence yield outcomes [36]. The choice between leys and permanent grasslands has a notable impact on DMY, with leys being more productive [37]. The age of leys also affects DMY, with two- and three-year-old leys achieving higher yields [38]. Furthermore, the presence of legumes in grassland leys can enhance DMY [39]. The impact of genotype-by-environment interactions on DMY in L. perenne cultivars further underscores the importance of considering environmental factors [40].

3.3. Forage Quality of Leys and Permanent Grasslands

Grasses and legumes differ significantly in their nutritional composition, with legumes generally offering higher crude protein (CP) and lower fibre content compared to grasses [41,42]. Research on both temporary leys and permanent grasslands have demonstrated the advantages of incorporating legumes, particularly T. pratense and M. sativa, which have been found to significantly enhance CP levels [43,44]. However, as these plants mature, their neutral detergent fibre (NDF) content tends to increase, while their NDF digestibility decreases [45,46]. This trade-off between plant maturity and nutritional value is crucial for pasture management. Additionally, nitrogen deficiency can influence this relationship by increasing the leaf-to-stem ratio, which improves NDF digestibility despite the higher fibre content [47]. These findings underscore the importance of balancing plant growth stages and nutrient management for optimal forage quality.

Our results, presented in Figure 4, align with other researchers’ studies, demonstrating a stable crude protein content over two years, with leys showing 14.7% in 2019 and 14.8% in 2020 while permanent grasslands exhibited slightly higher values of above 15% in both years. This indicates no significant difference (p = 0.18) in crude protein between leys and permanent grasslands. However, our data on the NDF content reveal a notable contrast: in 2019, leys had a NDF content of 47.1%, significantly (p < 0.05) lower than the 55.5% found in permanent grasslands. This trend was consistent in 2020, with leys showing 47.6% NDF compared to 58.5% in permanent grasslands. This notable difference underscores that leys provide a more digestible forage option than permanent grasslands, reinforcing their value in terms of fibre digestibility, while the inclusion of diverse pasture species remains essential for supporting the overall health of cattle and other ruminants [48].

Further supporting these findings, the importance of early cutting to maintain forage quality has been emphasised, as legumes generally offer higher digestibility and crude protein content compared to grasses [49]. Environmental factors, including vegetation characteristics and weather, significantly influence the variability in biomass production and forage quality [50]. Additionally, research on spring nitrogen application in Lolium multiflorum Lam. shows that higher nitrogen rates yield a higher crude protein content [51].

3.4. Differences in Fresh Matter Yield Components

The fresh matter yield composition was composed of four main components: sedges, herbs, grasses, and legumes (Figure 5). In 2019, the composition across the locations showed some variability. Legumes were a dominant component in Kėdainiai and Lazdijai, constituting over 50% of the total yield, while grasses and herbs were also present but to a lesser extent. In Šilalė, grasses dominated the yield, accounting for a significant portion of the fresh matter, while legumes were still prominent. In Zarasai, the yield was more balanced, with grasses and legumes both contributing substantially and sedges also present.

In 2020, the composition of the fresh matter yield changed notably in some locations. In Kėdainiai, the proportion of grasses increased significantly, surpassing legumes, which still made up a large part of the yield. Lazdijai continued to be dominated by legumes, but the presence of other components like grasses and herbs slightly decreased. Šilalė maintained a similar structure to 2019, with a dominant grass component, although the presence of legumes slightly declined. Zarasai, however, showed a marked shift, with legumes becoming more dominant, and the proportion of grasses decreased compared to the previous year.

Overall, the fresh matter yield composition of permanent grasslands varies across different locations and years, reflecting the influence of local environmental conditions and management practices. Different functional plant groups, such as grasses, legumes, herbs, and sedges, dominate under varying conditions, contributing to this variability [52,53,54]. Seasonal and locational factors, including shifts in weather patterns, likely drive these changes. For instance, the observed increase in grass dominance in Kėdainiai in 2020 indicates that specific environmental or management factors favoured grasses over other components, like legumes, in that particular year. These findings highlight the need for adaptive management strategies when optimising grasslands for forage or bioenergy production, accounting for fluctuating environmental conditions and their impact on yield composition.

4. Conclusions

The significant reduction in both the area and diversity of permanent grasslands underscores the importance of their conservation. Our study reveals that permanent grasslands support a much richer flora compared to leys, which predominantly consist of a limited number of cultivated species. Differences in dry matter yield and forage quality between leys and permanent grasslands suggest that adopting leys could increase productivity while reducing biodiversity. Meanwhile, permanent grasslands excel in biodiversity and fibre content, contributing to better digestive health.

Moreover, the results indicates that management practices, environmental conditions, and species selection play vital roles in influencing grassland productivity. To combat the ongoing decline of grasslands, it is essential to implement sustainable agricultural practices that promote grazing, mowing, and the preservation of native flora. Future efforts should focus on restoration strategies that not only enhance the ecological value of these ecosystems but also support local agricultural sustainability.