Research on the Influence of Fertilization System on the Production and Sustainability of Temporary Grasslands from Romania

Abstract

The analysis of the impact of the organic and mineral fertilization systems on the production and sustainability of the temporary grasslands in Romania represents a decisive step in establishing the optimal management in such a technology. The purpose of this research is to determine the influence of these two types of fertilization on hay production, floristic structure, chemical composition–nutritional quality, economic efficiency, and sustainability, in order to improve the cultural technology. The study was carried out in the area of Horezu, Romania. A mixture of five fodder plants was used in the study—Dactylis glomerata, Phleum pratense, Festuca pratensis, Lolium perenne, and Lotus corniculatus—which were sown in two fertilization systems: mineral and organic. The research was carried out between 2017 and 2020, very different years from a climatic point of view. The year 2017 was used to establish the autumn experience, so it is incomplete and was not used in the interpretation of the obtained results. The results of our research contribute to the implementation of better technology for the cultivation of temporary grasslands because the statistical interpretation established that they are significant for all the objectives pursued: production, floristic and chemical composition, and economic efficiency. We recommend small farmers reconsider the use of an organic fertilization system, as they can achieve maximum efficiency, improvement of all physical and chemical properties of the soil, and reduction of feed contamination.

1. Introduction

The increasing need for food due to population growth has led to significant intensification of the use of grassland areas, especially in the last 50 years [1]. The meadows located in the mountainous and submontane areas in Romania are one of the richest sources of natural biodiversity conservation in the entire European area [2]. They continue to be the least affected by the brutal and uncontrolled action of humans on nature, even after a period of 50 years of communism and over 30 years of mismanagement [3]. It is well known that any change in grassland ecosystem management destabilizes the biotic community structure, either positively or negatively [4]. This is done most frequently due to the specifics of the management applied to the meadows and depends particularly on the method of fertilization [5]. The organic fertilization system improves almost all components of the biotic community, whereas the mineral fertilization system acts differently, influencing it either positively or negatively. The mineral fertilization system intensifies biotic processes only if phosphorus is deficient in the soil [6]. The organic fertilization system contributes significantly to the stability of meadow ecosystems, having a direct effect on the floristic biodiversity and the quality of the fodder obtained [7,8].

The organic fertilization system contributes to obtaining a larger amount of food produced within a sustainable agricultural system that is more environmentally friendly, even though until recently the use of synthetic fertilizers in agriculture was emphasized as a crucial method for ensuring the supply of food for the increasing population [9]. Poor management of nitrogen obtained from manure ultimately contributes to the limited use of nitrogen in the food system, which leads to a considerable reduction in all the economic, social, and environmental benefits that can be achieved [10]. Due to the fact that the cost of nutrients has increased considerably in the last year, especially with the war in Ukraine, farmers in Europe and around the world must focus on increasing the efficiency of the amounts of nutrients used in all agricultural crops, not only in the fertilization of meadows. Their bad management will lead to a very low yield and exaggerated production costs, which in the end can contribute to incurring considerable losses at the farm level and implicitly at the level of the entire agricultural system, regardless of its type [11,12].

Our research has taken into account a particularly important factor in grassland culture, namely nutrient use efficiency, depending on the type of fertilization system on which it is established. According to the specialized literature, fertilizer management plays an important role in how nutrients are utilized, specifically the type of fertilization system from which they originate. Even if the purpose of using nutrients in agricultural crops is to considerably increase the production of agricultural systems, when it comes to sustainable agriculture, it is necessary to consider their origin and to try to use those nutrients originating from an organic fertilization system [13,14,15,16,17,18,19,20].

An important role in meadow cultures is played by the symbiotic relationship between plants and mycorrhizal fungi, which is directly influenced by the type of fertilization system used to establish the meadows. The type of phosphorus in the soil administered together with the fertilization system either positively or negatively influences this symbiosis; the raw form of phosphorous is not accessible to plants, due to the autotrophic component [21,22,23,24,25]. Several sources reported that worldwide phosphorus reserves are limited, with the possibility of phosphorus deposits being depleted in the near future and becoming increasingly expensive and difficult to find. The large-scale substitution of phosphorus in the soil, which is so necessary for meadow ecosystems, can be achieved through the more intensive use of the organic fertilization system [26,27,28,29,30]. Until the beginning of the war, Ukraine, which was a large producer of synthetic chemical fertilizers, was considered to be a cheap source of fertilizers, which in turn led to their massive use in all agricultural crops at the expense of technologies based on organic fertilization systems. Their excessive use has led to a high phosphorus content in the soil, which ultimately has the effect of blocking mycorrhizae and seriously disrupting grassland ecosystems [31,32,33,34].

At the global level, sown meadows are increasingly appreciated due to their unique floristic composition and biodiversity, which makes the promotion of techniques based on sustainable culture—directly influenced by the type of fertilization system—decisive in slowing down climate change and reducing greenhouse gases. At the same time, the property of grassland ecosystems is to offer more advantages to the natural systems from which they originate, which depends significantly on the type of nutrient management practiced. When using a certain type, as several authors state, the knowledge gained from long-term fertilization experiments on different types of meadows must be considered. We have concluded from the literature study that there has been relatively little research done on the impact of the organic fertilization system on production capacity and biodiversity, because at the European level, farmers avoid using solid manure fertilization of meadows, even though this has been proven to be a viable solution for maintaining and conserving biodiversity [35,36,37,38,39].

The biodiversity of temporary meadows brings great benefits to farmers and consumers because it constitutes a source of nutrients through the decomposition of organic matter, which blocks the washing of all chemical elements and has a positive influence on soil conservation and pollination of crops. In terms of grassland productivity at the European level, meadows play an important role as a source of fodder for both domestic and wild animals [40,41,42,43,44].

From the research carried out so far, it has been stated that dry matter yield increases because of the increase in the amount of fertilizer, but it has not been correlated with the new types of floristic structures appearing in the meadows. The efficiency of improving the level of use of nutrients is aimed at the development of sustainable production systems. Nutrient response efficiency (NRE) is a measure of ecosystem function that integrates productivity and nutrient retention (NRE) [44,45,46,47,48]. NRE is an index that reflects the ability of plants to obtain nutrients from the soil and use them for biomass production. Through the conducted research, an effort was made to determine the most effective and sustainable organic or mineral fertilization system that would result in obtaining higher amounts and qualities of dry matter (DM) per temporary grassland unit, in order to show the way to significantly improve the level of use and retention of nutrients (NUE and NRE) [49,50,51,52,53,54,55,56]. The only chance to improve the quality and sustainability of these extremely degraded meadows is the cultivation of temporary grasslands, which will be achieved through several types of fertilization systems and a reduced amount of chemical fertilizers.

The main objectives pursued in this research were the following: - the maximum efficiency of the doses used on the types of fertilization system studied were followed; the impact of the type of fertilization system on the production of dry mass (DM) was obtained; the dynamics of production evolution each year and on average were studied; the impact of the type of fertilization system on the floristic composition was studied; evaluation of the quality of the fodder was obtained by analysing the chemical composition; economic efficiency and the maximum profit obtained per surface unit was measured; the impact of the two types of agricultural land on their sustainability was compared. The dosages studied in the multi-year experiment have contributed considerably to the revitalization of these meadows and to the significant improvement of their quality and sustainability.

2. Material and Methods

2.1. General Characterization of the Researched Area

The studied area is in Horezu, Vâlcea County, which is a well-known agritourism area, in full development with a rich and diversified agritourism potential, in which many households and farms/agritourism households have specialized in animal husbandry and handicraft production [57]. The piedmont hills are the predominant landform, representing 45% of the county, with heights between 400 and 800 m.

The climate is temperate–continental, with moderate, mild weather [58]. For most of the year, it is relatively humid and cool, with normal rainfall values for sub-Carpathian depressions. The annual rainfall varies between 600 and 1200 mm.

The lands, according to their suitability, can be characterized as belonging par excel-lence to the mountain area and the hills. In relation to the terrain, the nature of the soil formation and soil cover presents great diversity: Haplic Luvisols, Eutric Cambisols, Haplic Phaeozems, Pellic Vertisols, Calcaric Regosols and/or Regosols in the sub-Carpathian and piedmont hills. The main restrictive factor of agricultural production in the territory is the slope of the land, which is frequently associated with eroded soils.

The natural setting with picturesque landscapes of unique beauty is an important attraction for tourists who want to visit the area. These attractions are complemented by the local tradition of production of the famous Horezu pottery, and many farms/agritourist households are focused mainly on animal husbandry. These must have sufficient areas occupied by grasslands to provide food both in summer and in winter [59,60,61]. Therefore, in the sub-Carpathian area of Oltenia, Romania, there are large areas of permanent grasslands in advanced stages of degradation, which no longer respond properly to surface measures. These surfaces require radical restoration, such as clearing and establishment of temporary grasslands, suitable to the conditions of an annual rainfall of over 700 mm and moderate temperatures [62].

2.2. Material and Methods

The research carried out in the Horezu–Vâlcea area and other localities in northern Oltenia, Romania, demonstrated the importance of fertilization to capitalize on the productive potential of temporary meadows. In normal climatic years, crops provided 6–8 t ha⁻¹ of dry matter, only in the presence of chemical or organic fertilizers administered in appropriate doses [63,64].

During the years of operation, fertilization was a basic measure for obtaining a high yield [65]. Doses of fertilizers differ depending on vegetation, soil and climatic conditions, grass/legume ratio, and method of use [66]. During the research period, an annual dose of 80 kg ha⁻¹ of nitrogen was applied, which proved to be very advantageous from an economic point of view, because in combination with the fertilization system, it gave significant yields, both quantitatively and qualitatively.

The temporary grassland was established in the spring of 2017 by sowing a complex mixture consisting of Dactylis glomerata 20% + Phleum pratense 15% + Festuca pratensis 15% + Lolium perenne 15% + Lotus corniculatus 35%.

The study took place on a plateau, in subdivided plots:

• Factor A—fertilization system, with the doses:

• a₁: chemical − 50 kg ha⁻¹ N + 50 kg ha⁻¹ P₂O₅ + 50 kg ha⁻¹ K₂O

• a₂: organic − 30 t ha⁻¹ manure + 50 kg ha⁻¹ P₂O₅ + 50 kg ha⁻¹ K₂O

The dimensions of the large plot were: length 10 m, width 8 m, surface 80 sqm; and of a small plot: 8 × 3 m = 24 sqm, of which 20 sqm were harvestable [62]. At the beginning, the aforementioned treatments of factor A (fertilization system), namely the chemical and organic fertilizers, were incorporated under the results. The study involved harvesting in hayfield mode with a mower; at each mowing, obtaining samples for gravimetric analysis and determining dry matter content [62,67,68].

The fertilizers used were ammonium nitrate and complex fertilizers of the type 15:15:15 and 12:52:0, along with manure, according to the theme of each experiment.

The floristic structure of the forage was determined based on gravimetric analyses [69]. The chemical analyses carried out in the laboratory sought to determine the feed content in crude protein, cellulose, phosphorus, potassium, and calcium:

• -. Dry Matter (DM) was determined by oven-drying at 60 °C until a constant mass was obtained;

• -. total nitrogen (Nt) was calculated by the Kjeldahl method, after which crude protein (PB) was calculated using the formula PB = Nt × 6.25;

• -. cellulose was measured by the photometric method through successive hydrolysis (boiling in 1.25% sulfuric acid solution, then in sodium hydroxide) and separating the mineral salts phosphorus (P), potassium (K), and calcium (Ca) after calcination at a temperature of 550 °C [58].

The results obtained for each variant, expressed in dry matter, were statistically processed according to the variance analysis method for the one factor experiments (ANOVA) [62,70,71]. In order to highlight the optimal options, the economic efficiency calculation was performed, taking into account costs and production. A series of economic indicators were calculated, namely: average yield, production cost, profit per surface unit, and profitability rate [2,10,72,73].

Average yield: $q_m=\frac{Q}{S}$ (t ha⁻¹); q_m = average yield per productive unit (t ha⁻¹); Q = total production (t); S = surface (ha). Production cost: Cp = $\frac{{\displaystyle \sum Ch}}{Q_t}$(€ t⁻¹); Cp = production cost per unit (€ t⁻¹); ∑Ch = total production costs (EUR); Q_t = total production (t). Profit: Pr_t = Q_v − ∑Ch; Pr_t = total profit (EUR); Q_v = total production in value units (Euro); ∑Ch = total production costs (EUR). Profitability rate: R_Pr = $\frac{{Pr}_t}{{\displaystyle \sum Ch}}\times 100$ (%); R_Pr = profitability rate (%); Pr_t = total profit (EUR); ∑Ch = total production costs (EUR).

3. Results

With the aim of achieving the objectives, this research was carried out at an agritourism farm in the Horezu area, Vâlcea County, Romania, which has an area of over 5.3 ha occupied by natural grasslands in an advanced stage of degradation. These must be transformed into temporary grasslands to provide food needed by farm animals, both in summer and in winter.

A particularly important link in the technology of temporary grasslands is fertilization, both basic and applied before sowing, along with land preparation and maintenance fertilization during exploitation [74]. In the hilly area of Oltenia, temporary grasslands would not be feasible without providing the necessary fertilizers, as the low soil fertility is a real limiting factor for these valuable crops [75,76,77]. Therefore, in this area characterized by very poor and strongly acidic soils, fertilizers are mandatory to ensure the emergence and persistence of eutrophic species of grasses and perennial legumes.

This research was aimed at identifying the influence of fertilization systems on the production of temporary grasslands in farms/agritourist households in Vâlcea County, Romania. This topic has not been thoroughly researched, so we felt it was imperative to completely understand it in order to improve the respective grasslands and to produce higher-quality, superior products.

The experiment lasted for a total of four years, including 2017, when the experimental design was created and the study officially began. As a result, data from 2017 were not considered for establishing the experiment’s final results.

Data were collected in 2018, 2019, and 2020, which were also the reference years of the research, when the influence of the fertilization system on the production of dry matter was investigated (Figure 1).

3.1. Climatic Characterization of the 2017–2020 Research Period

3.1.1. The Thermal Regime

The average annual temperature recorded in the area during the four years of experimentation generally exceeded the multi-year average. Thus, the average of the 2017 agricultural year was 10.6 °C, with a positive deviation of 0.4 °C compared to the multi-year average. The average temperature for the 2017 season was 17.4 °C, with a deviation of only +0.2 °C from the multi-year average (Table 1).

The 2018 agricultural year was the only one of the four years of experimentation in which the average annual temperature was below the multi-year normal, with a deviation of −0.1 °C. The seasonal average (April–September) exceeded the multi-year average by 0.5 °C.

The year 2019 was the warmest of the four experiments, with an average of 12.7 °C, 2.5 °C above the thermal norm (Table 1). Additionally, the year 2020 had a positive deviation from the multi-year average, but this was only +0.8 °C (Table 1).

3.1.2. Rainfall Regime

Regarding annual precipitation in the experimental area, it is on average 798 mm. In the months of April–September (in season), the recorded multi-year average is 453.2 mm. The amount of annual precipitation exceeded the multi-year average in three of the four years of experimentation (Table 1).

The agricultural year 2017 in which the experiments were established recorded the highest amount of precipitation among the four years of experimentation (1167 mm), 369 mm more than the multi-year average. This helped create a situation for good emergence and establishment of the seeded mixes.

In 2018, the amount of precipitation exceeded the multi-year average, registering 982.2 mm, or 184.2 mm above the average. During the growing season, the rainfall exceeded the multi-year average by 139.8 mm (Table 1).

The year 2019 was the poorest in precipitation, being the only one in which the annual precipitation average was not exceeded. A total of 740.5 mm of rain fell, and it was unevenly distributed, measuring 57.5 mm less than the multi-year average. If we analyze the precipitation that fell between April and September, it is higher than the multi-year average by more than 83 mm (536.6 mm compared to 453.2 mm).

In the last year of experimentation, 2020, the annual amount of precipitation exceeded the average by 137.2 mm. If we refer to the period from April to September, the precipitation that fell was very close to the average value (454.5 mm versus 453.2 mm), with a positive deviation of only 1.3 mm (Table 1).

Analyzing the data presented above, it can be seen that the second year of actual experimentation, 2019, was a very difficult year from the point of view of the thermal and pluviometric regime, with the average temperature being 12.7–2.5 °C higher than the thermal norm—and the total rainfall was 740.5 mm, unevenly distributed, or 57.5 mm less than the multi-year average (Table 1). These negative aspects are reflected very significantly in the very low production of hay obtained this year—only 5.54 t ha⁻¹ using the mineral fertilization system and 5.95 t ha⁻¹ using the organic fertilization system.

3.2. Dry Matter Production in the Period 2017–2020

The mineral fertilization system, considered as a control (50 kg ha⁻¹ N, 50 kg ha⁻¹ P₂O₅, 50 kg ha⁻¹ K₂O), produced a quantity of 1.38 t ha⁻¹ DM, while the organic fertilization system (30 t ha⁻¹ manure + 50 kg ha⁻¹ P₂O₅, 50 kg ha⁻¹ K₂O) increased by 115% more than the mineral one; or, in absolute values, by 1.38 t ha⁻¹, i.e., 2.72 t ha⁻¹ DM The increase was very significant (Table 2).

The data obtained confirm the very significant influence of organic fertilizers on the production and quality of forage, even from the first year, when the experience was established [77].

In the second year of vegetation, which was the first of actual experimentation, much higher productions were recorded, close to the productive potential of temporary grasslands.

On average, regardless of the annual dose of N kg ha⁻¹ fertilizer, the organic fertilization system continued to strongly influence feed production (Table 3).

Thus, basic mineral fertilization obtained production of 7.13 t ha⁻¹ DM, and the organic fertilization system obtained production of 9.46 t ha⁻¹, with 2.33 t ha⁻¹ DM, which is a very significant difference from a statistical point of view. The big difference between the two fertilization systems can be explained by, on one hand, the maximum effect of organic fertilizers manifesting in the second year of application, and on the other hand, the ability of mature plants to better utilize the available fertilizer in the second year of vegetation. The result suggests that 80 kg ha⁻¹ of nitrogen is recommended for temporary grasslands in the area where the experiment was conducted, in the second year of growth [78].

Consequently, in the third year of application 2019, manure still contributed to stimulating the production of dry matter (DM), but it was reduced in quantity (0.41 t ha⁻¹). Considering the ANOVA test results, it was found that there is no statistically significant difference between the control and test treatments (Table 3).

In terms of climate, the year 2020 showed some similarities to the year 2019 in the sense that rainfall proved to be deficient in the winter months, which yielded a minimum reserve of moisture in the soil. However, in 2020, the production of the temporary grassland was superior to that of the previous year.

Of the two fertilization systems, the organic one proved to be slightly superior, achieving on average a production of over 7.22 t ha⁻¹ DM, with 0.47 t ha⁻¹ more than the mineral fertilization system. The difference mentioned above is, as in the previous year, insignificant, as the effect of manure diminished greatly in the fourth year of application (Table 3).

During the actual experimentation period, 2018–2020, the temporary grassland from Horezu–Vâlcea produced different amounts depending on the fertilization system provided at the establishment (Table 3). Thus, on average, the grassland produced 6.47 t ha⁻¹ DM when the fertilization system at sowing was mineral (50 kg ha⁻¹ N, 50 kg ha⁻¹ P₂O₅, 50 kg ha⁻¹ K₂O) and 7.54 t ha⁻¹ DM with the organic fertilization system consisting of manure + 50 kg ha⁻¹ P₂O₅ and 50 kg ha⁻¹ K₂O, and an average annual dose of 80, N/P₂O₅/K₂O kg ha⁻¹ (Table 3).

The dry matter production of the grass sown in land fertilized with manure was higher by 18% (1.07 t ha⁻¹ DM), a very significant difference, which amply demonstrates the particularly important role of organic fertilizers in producing higher yields and sustainability in the temporary grasslands in the researched area (Table 3).

3.3. Annual Production Dynamics

The timing of the production of temporary grassland depended mainly on the year of vegetation and the weather. The highest productions, between 7.13–9.46 t ha⁻¹ DM, representing 35.5–38% of the total amount of dry matter harvested in four years (2017–2020), were made in the second year of vegetation, i.e., in 2018 (Table 4).

The lowest productions of 1.34–2.72 t ha⁻¹ DM, representing only 5–10.5% of the total production, were seen in the year of establishment of the temporary grassland (2017). In the third year (2019), unfavourable in terms of rainfall, production accounted for 21–23.25% of the total quantity, i.e., 5.54–5.95 t ha⁻¹ DM, a much lower production than in the fourth year (2020), which was more favourable in terms of precipitation during the growing season. In 2019, production ranged between 6.75–7.22 t ha⁻¹ DM, which accounts for 30–35.5% of the total production of the period 2017–2020. In terms of quantity and weight compared to global production, the values reported in 2020 approached those from 2018.

The fertilization system had a small influence on the annual dynamics of temporary grassland production [79]. However, in the first two years, the production of the grassland and its share compared to global production were higher in the organic fertilization system, after which the situation was reversed. For example, in the first year, the share of production for those with organic fertilizer was 10–11% and those with NPK (Nitrogen, Phosphorus and Potassium) only 5–6%. In the third year, the production of variants with manure represented 21%, and those with the mineral fertilization system, 23.25%.

The temporary meadow staggered its annual production on two mowings in the first and last year (2017 and 2020) and on three mowings in 2018 and 2019. In the first year, the production dynamics were similar for the two fertilization systems: 82–83% was achieved at the first harvest and 17–18% of the total annual production at the second harvest. In 2018, the first harvest had a share of 58–75%, the second of 11–24%, and the third of 12–18%.

The share of crops was slightly influenced by fertilization system, but fluctuated depending on the annual dose of nitrogen. In 2019, there was a special and rare situation: the first harvest, which usually represents about two-thirds of the annual production, had a low share of only 36–46%, the second harvest had a share of 34–44%, and the third of 17–23%. Consequently, in 2019, the annual dynamics of the grassland were balanced, much better than in other years, but the production of dry matter at the 3 harvests was only 5.54–5.95 t ha⁻¹, the lowest of the three years of experimentation.

In 2020, two very unbalanced harvests were seen, in the sense that the first harvest accounted for over 90% of annual production, while the second harvest contributed 7–10%. The above data show that the annual dynamics of the production of temporary grassland were primarily influenced by the weather and then by the treatments performed, which in one way or another were influenced only by the presence of a normal rainfall regime [80].

3.4. Floristic Structure

From the point of view of the floristic structure, the temporary meadow dominated in 2018 at the first mowing of grasses (Table 5). Depending on the treatment, they contributed between 71 and 75.5% of the yield, with the percentage of legumes fluctuating between 24.5 and 29%.

By utilising the organic fertilization system, the share of legumes was higher. Thus, by applying manure, the proportion of legumes was 29%, whereas by utilising the mineral fertilization system, the proportion was only 24.5% of the first harvest (Table 5). At the second harvest, the grass/legumes ratio was reversed, with the last group of plants having the highest share—63.5% in the mineral fertilization system and 70% in the organic fertilization system. There is a difference of 6.5% between the two types of fertilization system [79].

In the second year of production (2019), there was a decrease in the proportion of legumes (Table 5). These remained at a level of 17.5% on the mineral fertilization system, and on the organic one, the percentage was higher than 21% at the first harvest. At the second harvest, unlike the previous year, the grasses predominated in the floristic structure of the grassland, while the legumes were present in a small quantity, between 20–31%. Unlike in 2018, in 2019, there was a significant increase in the percentage of legumes—over 11%—in the mineral fertilization system, compared to the organic one, where it was only 20%.

However, legumes had a fairly high percentage—higher than the previous year—which demonstrates the special resistance of Lotus corniculatus (used as a legume in the temporary grassland) to severe drought conditions. It is well known that this species interrupts its growth in unfavorable conditions, resuming its vegetative cycle when conditions improve. The high percentage of legumes and lower percentage of grasses at the first harvest, as well as the appearance of weeds, show that part of the grasses perished in the vegetation in the previous year, with the birdsfoot trefoil surviving the conditions of excessive drought. The floristic structure was affected by the drought in 2019 and by the net deficient rainfall regime in 2020, which resulted in a series of minor modifications that are now fully explicable (Table 5). It is important to note, however, that in most variants, Lotus corniculatus was present in a proportion of 19–25% in the first harvest and 20–23% in the second harvest, thus contributing to the achievement of a very good quality fodder [81].

3.5. Chemical Composition

Laboratory analyses performed in the first year of experimentation (2018) highlighted the changes caused by fertilizers on the chemical composition of the feed harvested from the temporary grassland (Table 6). The crude protein varied between 12.93% in the 50 N, 50 P₂O₅, 50 K₂O fertilization system and 13.96% in the organic fertilization system. Consequently, organic fertilizers have yielded a higher protein content, which is explained primarily by the higher amount of legumes found in the vegetable carpet of the grassland. Regarding the dose of nitrogen, in both fertilization systems, the treatment with 80 kg ha⁻¹ N led to a higher protein content of the feed. The cellulose content ranged between 29.37–32.14% and was mainly influenced by the nitrogen dose. In both fertilization systems, the dose of N led to the percentage increase of cellulose as a result of the increase of the plant dimensions and implicitly of the development of the supporting mechanical tissues.

The phosphorus content of the feed was generally low, at or below the optimum values. Slightly higher values of 0.36% were found with the organic fertilization system. The low percentage of phosphorus in the feed is normal, taking into account the chemical properties specific to the soil on which it was grown, which is characterized by high acidity and an appreciable mobile aluminium content. Also due to the specific chemical properties of the soil, the potassium content of the feed is lower than the minimum threshold of 2%. The percentage values ranged between 1.68–1.80%, slightly higher in the organic fertilization system.

In acidic soil, which is permanently subjected to intense debasing processes, and in the presence of chemical fertilizers, the calcium content of the feed was also low, towards the lower allowed limit. The highest values, of 0.33%, were also found in the organic fertilization system. The results of chemical analyses performed on the harvested feed demonstrate the presence of proteins in normal proportion, but a generally low content of mineral substances.

3.6. Economic Efficiency

To determine the economic efficiency of the results obtained in the three effective years of research, the data entered in Table 7, which are calculated in euros (EUR), were analysed. This indicates that the type of agricultural land has a significant impact on the economic effectiveness of the meadow planted in Horezu–Vâlcea, Romania.

On average throughout the course of the experiment’s three years, the total costs per surface unit were relatively close, ranging between EUR 570.98 ha⁻¹ in the variant using the mineral fertilization system and EUR 569.34 ha⁻¹ in the version using 30 t of fertilization system per ha, manure +50 P 50 K (Table 7 and Figure 2).

It can also be observed that although the production costs were approximately the same, a considerably higher price was obtained with the organic fertilization system, of EUR 210.53 t⁻¹ DM, which made the profit recorded for this option significant higher—EUR 1018.03 t⁻¹ DM, compared to the mineral variant where it was only EUR 518.71 t⁻¹ DM. (Figure 2). The profitability rate recorded for the three years of experimentation ranges between 90.84% for the variants with the mineral fertilization system and 178.8% for the variants with the organic fertilization system (Table 7).

Therefore, using the organic fertilization system is advised as being cost-effective for agricultural practices in the Romanian sub-Carpathian region under study.

4. Discussion

From previous studies, it has been observed that for meadows to express their maximum growth potential, they require adequate soil fertility [2,10,16,82]. The study carried out by us was located in a sub-mountainous and hilly area in the Horezu, Romania, area, where the soil is poorer in nutrients and is affected by different forms of surface erosion. In order to support the owners of farms and agritourism households, we conducted this research that significantly contributed to establishing a way of cultivating meadows that would bring considerable profit while maintaining their quality and sustainability. We designed a model of sustainable exploitation of the meadows in the area, based on the application at the establishment of an organic fertilization system, which was supplemented annually by a reduced amount of N fertilizer (80 kg ha⁻¹). In this research, through effective planning of the type of fertilization, we established a nutrient management system that ensures maximum yield, high nutritional value, good storage rate, and a considerable impact in terms of sustainability [13,16,83].

At the same time, we tried an integrated approach, taking into account the good climate conditions in the area—, which include significant amounts of precipitation, over 700 mm year⁻¹, even though it is unevenly distributed—throughout the vegetation period. In some years of research, they significantly influenced the production obtained; for example, in 2019, a production of only 5.9 t ha⁻¹ DM was obtained from the organic fertilization system.

In order to improve the quality of the fodder obtained and increase the level of regeneration of the amount of nitrogen in the soil, in addition to the four species of grass—Dactylis glomerata 20% + Phleum pratense 15% + Festuca pratensis 15% + Lolium perenne 15%—the mixture also used a species of leguminous Lotus corniculatus in a proportion higher than 35%, which proved significantly effective in terms of the two aspects pursued [4,11,84]. The mixture was designed this way, because this is the only way to obtain a quality feed rich in proteins and with high digestibility, which facilitates the digestion process of farm animals, a fact that leads to consistent benefits in animal husbandry systems in agritourism farms [6,13,16]. The cultivated legume has a high rate of biological nitrogen fixation, which also ensures success in terms of sustainability, being strongly recommended for the climate and soil conditions of the researched area [7,11,84].

Considering the influence of the type of fertilization system on the productivity of temporary meadows, it was found that the organic fertilization system had a significantly positive influence, leading to a much higher production, starting from the first research year 2017, when it was higher by 1.38 t ha⁻¹ DM [8,50,85]. Also, a very significant difference of 2.33 t ha⁻¹ DM was obtained in the second year of research (2018), decreasing considerably in the third year, when the lack of precipitation negatively influenced the productions obtained on both types of agricultural land [26,33,63,78]. In the fourth year, the influence of the organic agricultural fund/agricultural system of organic fertilization decreased to be practically insignificant, only 0.47 t ha⁻¹ DM, which is due, as is well known from the specialized literature, to the fact that the positive effect of the organic agricultural fund/the agricultural system of organic fertilization is manifested for a maximum period of three years, an aspect also proven by us in this research [8,35,46,76].

The favorable effect of the organic fertilization system used in our research on feed production is also very clear from the average production obtained over the three effective years of research (Table 3). It can be seen that the limit difference (LSD) was very significant at 1.07 t ha⁻¹ DM, a fact that attests to the use of sustainable agricultural resources such as manure as a positive influence both on the production obtained and on the improvement of the properties and sustainability of lands cultivated with such meadows [52,63,77,78,79,80,81]. Regarding the annual dynamics of the production of the temporary meadow, from the data shown in Table 4, it is demonstrated that it was influenced by the evolution of specific climate and environmental conditions and then by the type of fertilization system used, positively influencing the productive yield, in the presence of a normal rainfall regime, especially in critical periods, during the vegetation season [40,54,66,85].

A very important component of the quality and sustainability of the meadows is their floristic structure. The data shown in Table 5 indicate that the proportion of legumes in the researched mixture is higher by more than 4% in the first two years of the organic fertilization system, a point that demonstrates their superior quality, as they tend to be preferred by animals bred on the agritourist farms in the area [14,50,75]. The floristic composition of the meadows in Romanian agritourism farms represents a very significant asset in the attraction of tourists, because they appreciate and react positively to the beauty and purity of the rustic environment, which can be very varied due to the multitude of plant species existing in a meadow [43,48,67,68]. Tourists can also participate with their host in all the activities that take place in a meadow; working on it can have a special therapeutic effect on tourists, as it can contribute considerably to improving their mental health and reducing stress levels, which is a common problem for people working in the corporate business environment [35,70,86,87,88,89,90].

Regarding the chemical composition of the two types of fodder obtained in different fertilization systems, it was found to be better in the organic fertilization system (Table 6), which is clearly superior to the one obtained in the mineral fertilization system. In the table, it is noted that the percentage of crude protein in the organic system is higher by 1.03%, that of cellulose by 2.77%, and that of P, K, and Ca is also higher. This fact confirms that the results obtained by us are similar to those obtained by other researchers, that the organic fertilization system plays a significant role in improving the quality and digestibility of forage, and that it makes an essential contribution to maintaining their sustainability [16,27,34,42,52,71,82,83,84,85].

A very significant contribution of the studied topic is related to economic efficiency. Analysing the data shown in Table 7, it is obvious that economic efficiency is much higher for the meadows sown on the organic fertilization system, since the profit obtained per hectare is higher by more than EUR 500 than on the mineral fertilization system. This considerable profit is primarily due to the selling price, which is higher by EUR 42.11 t⁻¹ DM, of the organic fertilization system compared to the mineral one, due to its special quality, as it is clearly differentiated from the point of view of the floristic structure and the crude protein and digestible cellulose content [1,2,3,28,37]. A positive effect on the increase in profit and the rate of profitability of the meadows sown on the organic fertilization system was also determined by lowering expenses per unit of DM, which were lower by EUR 12.74 t⁻¹ DM compared to those on the mineral fertilization system; these expenses correlated with higher sale prices, leading to a profitability rate of over 178% [40,49,71,72,73]. All these significant results aimed at economic efficiency that we obtained in this research confirm the discoveries made by other researchers in other studies of the same research field and attest to the fact that even on lands that are more sloping, degraded, and less fertile, high yields of very good quality can be obtained, even if the fertilization system used is an organic–sustainable one [1,2,3,28,75,76,77,78,79,80,81,82,83,84,85].

The average yearly yield of the sown meadows was greatly affected by significant climate changes expressed mainly in recent years, our research found, and this can be considered another significant and relatively new achievement [10,24,35,54,79]. This is demonstrated by the fact that in the second year of the study, 2019, a climate anomaly with low precipitation and a very uneven distribution during the vegetation period appeared. This led to production levels being significantly lower, by more than 1.5 t ha⁻¹ DM, when compared to the multi-year average production [58,59,62]. Additionally, through the research carried out and the results obtained, it was demonstrated that the mixture of fodder species used by us, composed of four species of grass—Dactylis glomerata 20% + Phleum pratense 15% + Festuca pratensis 15% + Lolium perenne 15%—and a leguminous species Lotus corniculatus, in a higher proportion of 35%, achieved performance that far exceeded the average performance of all species cultivated in monoculture (yield and maximum efficiency), in the Horezu area of Romania, a finding confirmed by comparison with studies previously carried out by other researchers [26,42,74,76].

5. Conclusions

From the specialized literature, it has been observed that there are several research studies aimed at temporary meadows, but the novelty of this research consists of trying to establish the rates of fertilization with different types of nutrients necessary to achieve a high performance of plants and to achieve maximum profitability. Monitoring of the behavior of the sown meadows was carried out in the special technological conditions of farms/agritourism households, where the emphasis must be placed on the use of the better variant based on an organic fertilization system. By examining the impact of the fertilization system on forage production and quality, as well as the annual dynamics of production, the distinctive character of this paper lies in its efforts to improve seeded grassland technology and increase forage production in Oltenia, Romania.

Research has also confirmed the finding emphasized by other researchers, that the mixture formed by grasses and forage legumes makes a significant contribution to reducing the rate of nitrogen fertilization due to the ability of legumes to fix molecular nitrogen from the atmosphere. The floristic composition of the meadows in the researched area ofHorezu resulting from the sown mixture can be the most important asset for attracting tourists, in addition to their pleasure at participating effectively with their hosts in the work in the natural and sown meadows. It is well known from previous research results that traditional fertilization practices based on flat rates are not able to ensure the synchronization of nitrogen and other nutrient requirements of sown grasslands. Our experience proves that, especially in the new global geopolitical and economic conditions, radical measures must be taken for the maximum utilization of all nutritional resources and especially those from organic fertilizers. The war in Ukraine has led to an excessive increase in the price of energy and synthetic chemical fertilizers; therefore, all new research carried out must address topics that consider increasing the efficiency and improving the management of the supply and use of all nutrients, regardless of their origin and the maximum limitation of losses of nitrogen and other nutrients in the soil. Considering the perspectives presented above, we have experimentally developed a reliable and efficient long-term field data protocol that includes a range of soils, climatic conditions, and forage plant species typical of areas the submontane region and hills of Romania. Thus, our findings have led to the realization of significant performance in terms of yield, economic efficiency, and rate of return, while protecting and enhancing the sustainability of the more degraded lands studied. We are aware that, due to the complexity of the interaction between the components of grassland ecosystems, the research could not fully account for each of the specific environmental conditions, but we have attempted to make a significant contribution to the review of future technologies and approaches nationally and internationally.

Author Contributions

Conceptualization, J.C., A.C. and M.M.; methodology, J.C., A.C., T.I., M.M. and A.C.C.; software, J.C., A.C. and M.M.; validation, J.C., A.C., T.I., M.M. and A.C.C.; formal analysis, J.C., A.C., T.I., M.M. and A.C.C.; investigation, J.C., A.C., T.I., M.M. and A.C.C.; resources, J.C., A.C., T.I., M.M. and A.C.C.; data curation, J.C. and M.M.; writing—original draft preparation, M.M.; writing—review and editing, J.C., A.C.C., T.I., M.M. and A.C.C.; visualization, J.C., A.C., T.I., M.M. and A.C.C.; supervision, J.C., A.C. and T.I.; research administration, J.C., A.C., T.I., M.M. and A.C.C. All authors have read and agreed to the published version of the manuscript.

Data Availability Statement

Not applicable.

Acknowledgments

We thank the University of Craiova, the Faculty of Agronomy and University of Life Sciences ”King Mihai I” from Timişoara and the Research Institute for Biosecurity and Bioengineering in Timisoara.

Conflicts of Interest

The authors declare no conflict of interest.

Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Figures and Tables

Figure 1. Aspects of the research field.

Figure 2. The influence of the agricultural fund on the efficiency of the sown meadow from Horezu–Vâlcea, Romania (average 2018–2020).

Table 1

The thermal and pluviometry regime of the area.

Specification	Average/Sum
	Annually		Growing Season		Annually		Growing Season
	T(°C)	Rainfall(mm)	T(°C)	Rainfall(mm)	T(°C)	Rainfall(mm)	T(°C)	Rainfall(mm)
2017					2018
Average/Sum	10.6	1167.0	17.4	731.0	10.1	982.2	17.7	593.0
Multi-yearaverage	10.2	798.0	17.2	453.2	10.2	798.0	17.2	453.2
Deviation	+0.4	+369.0	+0.2	+277.8	−0.1	+184.2	+0.5	+139.8
2019					2020
Average/Sum	12.7	740.5	18.9	536.6	11.0	935.2	18.5	454.5
Multi-yearaverage	10.2	798.0	17.2	453.2	10.2	798.0	17.2	453.2
Deviation	+2.5	−57.5	+1.7	+83.4	+0.8	+137.2	+1.3	+1.3

Source: Processing according to Vâlcea weather station and own data.

Table 2

The influence of the fertilization system on the production of temporary grassland (t ha⁻¹ DM, 2017).

No.	Variant	Absolute Yield(t ha−1 DM)	%	Difference	Significance
1	50 N, 50 P2O5, 50 K2O	1.34	100	-	Control
2	30 t ha−1 manure + 50 P2O5, 50 K2O	2.72	215	1.38	***

LSD (The limit difference) 5% = 0.15 t ha⁻¹ DM; LSD 1% = 0.35 t ha⁻¹ DM; LSD 0.1% = 1.13 t ha⁻¹ DM; *** Very significant.

Table 3

The influence of the fertilization system on the production of temporary grassland (t ha⁻¹ DM, 2018–2020).

No.	Year	Variant	The AnnualDose of N(Kg ha−1)	Absolute Yield(t ha−1 DM)	%	Difference	Significance
1.	2018	50 N, 50 P2O5, 50 K2O	80	7.13	100	-	Control
		30 t ha−1 manure + 50 P2O5, 50 K2O	80	9.46	132	2.33	* * *
LSD 5% = 0.30 t ha−1 DM; LSD 1% = 0.69 t ha−1 DM; LSD 0.1% = 2.33 t ha−1 DM
2.	2019	50 N, 50 P2O5,50 K2O	80	5.54	100	-	Control
		30 t ha−1 manure + 50 P2O5, 50 K2O	80	5.95	109	0.41	-
LSD 5% = 0.45 t ha−1 DM; LSD 1% = 1.06 t ha−1 DM; LSD 0.1% = 3.37 t ha−1 DM
3.	2020	50 N, 50 P2O5, 50 K2O	80	6.75	100	-	Control
		30 t ha−1 manure + 50 P2O5, 50 K2O	80	7.22	107	0.47	-
LSD 5% = 1.14 t ha−1 DM; LSD 1% = 2.64 t ha−1 DM; LSD 0.1% = 8.41 t ha−1 DM
4.	Average2018–2020	50 N, 50 P2O5, 50 K2O	80	6.47	100	-	Control
		30 t ha−1 manure +50 P2O5, 50 K2O	80	7.54	118	1.07	* * *
LSD 5% = 0.24 t ha−1 DM; LSD 1% = 0.36 t ha−1 DM; LSD 0,1% = 0.58 t ha−1 DM

LSD (The limit difference); *** Very significant.

Table 4

The dynamics per year of the production of the temporary grassland from Horezu–Vâlcea (2017–2020).

Fertilization System	The Annual Dose of N (kg ha−1)	Year 2017		Year 2018		Year 2019		Year 2020
		t ha−1 DM	%	t ha−1DM	%	t ha−1DM	%	t ha−1DM	%
50 N, 50 P2O5, 50 K2O	80	1.34	5.75	7.13	35.5	5.54	23.25	6.75	35.5
30 t ha−1 manure +50 P2O5, 50 K2O	80	2.72	10.5	9.46	38	5.95	21	7.22	30.5

Table 5

The floristic structure of the production of the temporary grassland in years 2018, 2019, 2020 (%).

No.	Year	Fertilization System	First Harvest *		Second Harvest *
			Grasses(%)	Legumes(%)	Grasses(%)	Legumes(%)
1.	2018	50 N, 50 P2O5, 50 K2O	75.5	24.5	36.5	63.5
		30 t ha−1 manure + 50 P2O5, 50 K2O	71	29	30	70
2.	2019	50 N, 50 P2O5, 50 K2O	82.5	17.5	69	31
		30 t ha−1 manure + 50 P2O5, 50 K2O	79	21	80	20
3.	2020	50 N, 50 P2O5, 50 K2O	72.5	25	73	23
		30 t ha−1 manure + 50 P2O5, 50 K2O	77	19	75	20

* The difference up to 100% is represented by weeds.

Table 6

The influence of the fertilization system on the chemical composition of feed.

Variant	Annual Doseof N (kg ha−1)	CrudeProtein(%)	Cellulose(%)	P(%)	K(%)	Ca(%)
FertilizationSystem
50 N, 50 P2O5, 50 K2O	80	12.93	29.37	0.32	1.68	0.3
30 t ha−1 manure +50 P2O5,50 K2O	80	13.96	32.14	0.36	1.8	0.33

Table 7

The influence of the agricultural fund on the economic efficiency of the meadow sown in Horezu–Vâlcea, Romania (average 2018–2020).

Fertilization System	Production Average (t ha−1 DM)	TotalCosts (EUR ha−1)	Production Costs (EUR t−1 DM)	Price of Sale * (EUR t−1 DM)	Value of Production (EUR ha−1)	Profit(EUR ha−1)	Profitability Rate (%)
50 N, 50 P2O5, 50 K2O	6.47	570.98	88.24	168.42	1089.68	518.71	90.84
30 t/ha manure + 50 P2O5,50 K2O	7.54	569.34	75.5	210.53	1587.37	1018.03	178.8

* Price of the free market in the Horezu–Vâlcea area.

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