Assessment of Management Practices to Prevent Soil Degradation Threats on Lithuanian Acid Soils

Abstract

An assessment of soil characteristics pertaining to their suitability for agricultural use in general is necessary to reverse the declining trend of soil quality and to ensure sustainable agriculture. The aim of this study was to determine the soil resistance (SRI) and degradation indices (SDI) under different agrotechniques and to find out whether management-induced changes are large enough to reduce soil degradation. The study was based on the comparison of physicochemical data of 3 long-term experiments conducted in the western part of Lithuania. Changes in soil properties over the past 20 years (1999–2019) have been determined. The most commonly used measures in Lithuania, such as soil liming, manuring, residue maintenance, and tillage, were selected for the analysis. The analysis carried out showed that the soil, which was fertilized with manure, had a higher value of soil quality parameters compared to natural Retisol: organic matter (by 0.53 percentage points), total nitrogen (by 0.04 percentage points), and the available amounts of phosphorus (by 69 mg/kg) and potassium (by 6.6 mg/kg). The assessment of the relative annual change in SOC content revealed that long-term soil manuring has significant SOC sequestration capability. Among the soil management techniques examined, it appeared that the greatest relative annual change (0.47 g kg⁻¹yr⁻¹) in SOC content was noted in manured soil. The results indicate that the higher degradation, and resistance values were observed in acid soil (pH 4.2), where liming was applied, indicating greater sensitivity to degradation. Based on analyzed indices, the agricultural practices ranked as: manuring > residue management > reduced tillage > liming. The lowest SRI values were obtained for low level of nutrients (from −0.11 to 0.89), organic carbon (from −0.72 to −0.49), and pH (from −0.25 to –0.1), indicating that these properties are more sensitive to applied agricultural practices compared to others. All these findings provide information for promoting better soil management, soil protection, land use planning, and the planning of remedial measures, especially in the most afflicted areas.

1. Introduction

Soil is an essential natural resource to humankind, and it is essential to the proper functioning of the ecosystem services. The Earth’s population is expected to reach 9.7 billion people by 2050, and in order to ensure food sufficiency, there has been a corresponding increase in land use intensification. However, the high demand that followed led to an irrational use of the agricultural resources that were available, which ultimately resulted in soil acidification, salinization, pollution, a decline in global biodiversity, and other forms of worldwide soil degradation that negatively impacted normal food production and posed a threat to human health [1]. Soil degradation can be defined as the loss of the soil’s capacity to provide ecosystem services and functions. The primary problems caused by soil degradation are the reduction in carbon and nitrogen pools, biomass activities, the loss of water retention capacity leading to decreased porosity, detachment of soil particles by soil erosion and, ultimately, the productivity of agriculture [2]. Orchard et al. [3] specified that one of the main ways to lessen soil deterioration is through the sustainable land use planning and management. Management of biomass, soil structure, water storage, nitrogen cycling, biological activity, and diversity are defined as key aspects of land preservation that are related to soil quality and are achievable only through it [4].

The most important drivers of soil degradation encompass changes in land use [5], excessive consumption of fertilizers in agricultural areas [6], overgrazing [7], and topography and climate. According to the European Commission, unsustainable agricultural management methods have caused up to 60–70% of Europe’s soils to degrade, and as a result, soils have significantly lost their ability to deliver ecosystem services [8]. Thus, the need for innovative technological solutions arises from ecological imbalances and deteriorating soil conditions. Simple, cost-effective, and adaptable strategies are required to successfully adapt to and mitigate climate change through agricultural management [9,10], which support the long-term sustainable use of resources and eco-efficiency [11]. Soil acidity is among the major land degradation problems worldwide. Acid soils make up approximately 30% of the world’s total land area and more than 50% of the world’s potentially arable lands [12]. Soil acidity can decrease crop productivity as it induces the immobilization of several nutrients, making them unavailable for plants while solubilizing several other elements, like Al, which results in a toxic environment for plants. It is estimated that intensive agricultural practices and synthetic fertilizers are responsible for more than 50% of worldwide farming land acidification [13]. The management of acid soils should aim to increase their potential for production by adding amendments to neutralize the acidity and changing farming techniques to achieve the highest possible crop yields. Neutralization of soil reaction is very important in maintaining optimum availability of soil nutrients and reducing possible harmful effects [14]. Lime is the most widely used additive to reduce the negative effects of soil acidity [15]. In addition to increasing soil pH via its dissolution products, lime supplies Ca²⁺ and Mg²⁺ and reduces Al³⁺, improving the availability of water and other nutrients to plants [16]. However, excessive liming can raise the soil pH above the suitable range for crop development, resulting in undesirable effects, such as low availability of metal micronutrients (e.g., copper, iron, zinc, and manganese) [17]. Scientific interest in soil conservation strategies such as minimal tillage, both organic and inorganic fertilization, and residue management—all of which contribute to enhancing soil organic carbon (SOC), natural soil fertility, and maintaining soil health—has increased over the past few decades [18,19,20]. Strengthening acid soils’ ability to accumulate carbon would increase soil quality and contribute to minimizing greenhouse gas emissions. Particular attention must be given to the selection of appropriate management type, particularly in acidic regions where low soil fertility and SOC content are major obstacles to effective agricultural productivity [21]. Under such circumstances, the selection and application of suitable agrotechniques, for instance, by adding farmyard manure or other organic fertilizers to the liming process, can effectively boost the availability of nutrients that restrict soil productivity while also improving soil structure and carbon storage [22]. Similar studies have shown that integrated use of sustainable soil management techniques could improve soil health status, highlighting their importance for boosting SOC stocks and stability while lowering concerns related to land degradation and CO₂ emissions. Therefore, reasonable management techniques, particularly sustainable fertilization, are desperately needed [23,24,25,26].

Management of acid soils needs strategic research, integrating soil management with environmentally friendly technologies for sustainable crop production within appropriate socio-economic and policy considerations. Overall, adoption of improved soil management practices is essential to adapting to the changing climate and meeting the needs of growing populations for food and raw materials for industries. Recently, identification of appropriate soil resistance and degradation indices for assessing sustainable use of soil has received increased attention. The aim of this study was (1) to determine soil degradation and resistance indices under different agricultural management practices and (2) to find out whether management-induced changes are large enough to have the potential to reduce soil degradation.

In general, the results of this study can represent the most suitable and susceptible indices and analyzing approaches to evaluate soil quality and degradation under different acid soil management techniques. Furthermore, suitable approaches for evaluating the effects of soil management changes and practices are introduced. This information will further our understanding of how to increase acid soil resilience in the face of environmental change with appropriate management. This research is especially relevant, given the economic, social, and environmental impact that future climate change scenarios predict for acid soil ecosystems.

2. Materials and Methods

2.1. Study Area

The study was based on comparing physicochemical indicator data from 3 long-term experiments conducted in the western part of Lithuania. Changes in soil properties during the period of 1999–2019 were identified. The most common measures applied in Lithuania, such as soil liming, manuring, residue maintenance, and tillage, have been selected to be analyzed.

Experiments with different applied agrotechniques were conducted at the Vėžaičiai Branch, Institute of Agriculture of the Lithuanian Research Centre for Agriculture and Forestry (LAMMC) (55°41′37.7″ N 21°29′57.4″ E) and selected for soil degradation intensity and soil sustainability assessment. The site is situated on the eastern fringe of the Coastal Lowland (Western Lithuania) and has a maritime climate where the mean annual precipitation of 748 mm exceeds the mean evapotranspiration of 512 mm, and the average annual air temperature is 6.7 °C. The soil in the study site was classified as naturally acid moraine loam, Bathygleyic Dystric Glossic Retisol (WRB, 2014), in which the clay content (<0.002 mm) constituted approximately 15.0%. According to the content of clay particles, the soil profile is differentiated into alluvial and illuvial horizons whose diagnostic horizons are: A (0–27 cm)—El (27–55 cm)—ElB (55–80 cm)—BtEl (80–105 cm)—BCg (105–120 cm). During this study, different types of agrotechniques were analyzed, including: soil liming (experiment I), manuring and residue maintenance (experiment II), and different tillage (experiment III) (Figure 1).

The liming experiment (experiment I) was started in 1949. Prior to the establishment of the experiment in 1949, the following agricultural parameters were evaluated: the unlimed soil was moderate in humus status (humus—2.43%, organic carbon (Corg)—1.41%), high in mobile phosphorus (P₂O₅) and potassium (K₂O) content (265 and 294 mg kg⁻¹ soil, respectively), and moderate in mobile aluminum (Al) content (73.3 mg kg⁻¹), with pH 4.08. In 1949, two liming rates—0.5 (3.3 t ha⁻¹ CaCO₃ every 7 years) and 2.0 (15.0 t ha⁻¹ CaCO₃ every 3–4 years)—were used for liming with pulverized limestone (92.5 percent CaCO₃), depending on the hydrolytic acidity of the soil. The soil was limed systematically: in 1949, the primary liming was conducted with slaked lime; in 1964, liming with slaked lime was repeated; and in the period of 1985–2005, the soil was limed periodically every 3–4 years in a seven-field rotation, incorporating powdered limestone at 2.0 rates (15 t ha⁻¹ CaCO₃) chosen according to the soil hydrolytic acidity. Lime was applied to the soil at a depth of 7–12 cm using a cultivator after it had been scattered on the soil’s surface. The soil was regularly limed until 2005. From 2005 until 2019, the soil was not limed, and changes in the characteristics of the soil were observed.

The crops were fertilized with mineral fertilizers. Plant protection products (pesticides) were used. Soil tillage was conventional plowing. The net plot size was 11.5 × 6.5 m = 74.75 m². A randomized, complete block design with three replications was used. The treatments were assigned randomly.

In order to evaluate the effects of various organic fertilizers, farmyard manure (FYM) (60 t ha⁻¹) and alternative organic fertilizers (wheat straw, oilseed rape residues, roots, stubble, and perennial grasses) were incorporated into the soil (experiment II). In the years when the experiment had been first established (1959), the thickness of the soil arable layer was 19–22 cm, soil pH_KCl—4.2–4.4. The soil was very low in phosphorus (50–60 mg kg ^–1), low in potassium (130–180 mg kg ^–1) and moderate in humus content (2.6–2.9%), with soil carbonates lying deeper than 2 m below the surface. For the soil to maintain its optimal pH_KCl (5.8–6.0), a 1.0 rate of lime (3.65 t ha⁻¹) was applied every 5 years, and 60 t ha⁻¹ of farmyard manure were applied during every rotation. Solid cattle manure used for fertilization contained 14.5% dry matter, 17.8% organic matter, 0.4% total N, 0.3% P₂O₅, 0.7% K₂O, 2668 mg kg⁻¹ Ca, and 692 mg kg⁻¹ Mg, with a pH_KCl of 8.5. The entire period included fertilization, with alternative organic fertilizers used for cultivation. Depending on the crops grown in the rotation, as alternative organic fertilizers, oilseed rape stubble, the green mass of a lupine–oats mixture, winter wheat straw, and perennial grasses were used. All treatments were equally fertilized with mineral fertilizers (background fertilization). Fungicides and insecticides were used in case of necessity; herbicides were not used at all. In a randomized block design, each treatment has been replicated three times (plot size of 4.25 m × 6 m).

The tillage experiment (experiment III) was carried out in 2003 in the experimental crop rotation field. The geographical location of the site is lat. 55°72′ N, long. 21°46′ E. The soil was formed on medium-moraine loam with a texture of sandy loam (clay particles—13–15%), whose pH at the beginning of the trial was 5.1–5.3. The soil is moderate in humus status (humus—2.43%, Corg—1.41%), moderate in mobile P₂O₅ content, and high in mobile K₂O (106 and 270 mg kg⁻¹ soil, respectively). The experiment included two different tillage methods: deep plowing (22–25 cm) and plowless tillage (7–10 cm). Deep and shallow plowing were carried out with plows fitted with semi-screw moldboards. Deep and shallow plowing were performed three weeks after scraping (at the depth of 6–8 cm). In the plowless tillage treatment, soil cultivation was conducted only after scraping. Pre-sowing tillage was the same in all treatments of the primary soil tillage: cultivation with a combined pre-sowing soil tillage cultivator. Crops were fertilized with mineral fertilizers. Plant protection products (pesticides) were used. Annually, after the harvesting of each crop of the rotation and before the primary soil tillage, 400 kg of CaCO₃ was spread to prevent soil acidification. The net plot size was 10 × 5 m = 50 m². A randomized complete block design with four replications was used. The treatments were assigned randomly.

Immature spontaneous forest was picked as the control treatment because there is spontaneous birch about 25 years old, so there is no anthropogenic activity.

2.2. Soil Sampling and Methods of Analyses

Every year (during the period of 1999–2019) in autumn, soil samples were collected from the upper soil layer (0–20 cm) immediately after the harvest. Using a steel auger, soil samples have been collected with three replicates. The total number of samples that were analyzed during the entire study period was 243. After leaving the samples to air dry, all visible roots and plant remnants were hand-extracted. Following that, the samples were crushed, passed through a 2 mm sieve, and thoroughly mixed. A 0.2 mm sieve was used to separate the soil samples in order to analyze the SOC content. The sieved soil was dried for sixteen hours at 105 °C in an oven.

Chemical investigations were performed in the Chemical Research Laboratory of LAMMC. Using an IONLAB pH meter, the pH_KCl of the soil was measured in accordance with ISO 10390:2005 standard [27] (soil–solution ratio 1:2.5). The method employed for determining the soil’s organic carbon content (SOC) was ISO 10694: 1995 [28]. The Kjeldahl method was used to quantify the total nitrogen (N_total) in the soil; the Egner–Riehm–Domingo (A-L) method was used to determine the potassium (K₂O) and plant-available phosphorus (P₂O₅). Mobile aluminum (Al³⁺) was determined in accordance with ISO 14254:2018 [29].

Determination of SOC transformation processes. To determine the actual effects of different soil management techniques on SOC sequestration, the annual change in SOC content under control treatment (CT) was subtracted from that under each management technique (MR) during the experimental period, resulting in a relative annual change in SOC content (RAC), which was calculated as follows:

$$RAC=\frac{{\left({SOC}_t-{SOC}_0\right)}_{\mathrm{TR}}-{\left({SOC}_t-{SOC}_0\right)}_{\mathrm{CK}}}{t}$$

(1)

where SOC₀ and SOC_t are the SOC contents of the initial and final year during the experiments, respectively, and t is the period of each experiment.

The carbon sequestration period can be employed as a measurement for determining the potential for carbon sequestration under various soil management practices:

SP = BD × RAC × D × 0.1

(2)

where BD is the soil bulk density (Mg m³) and D is the thickness of the soil layer (cm; a value 20 cm was used here).

2.3. Calculation of Soil Degradation and Soil Resistances Indices

The soil degradation index (SDI) was calculated using the following equation developed by Zhao et al. [30].

$$SDI=\frac{X_a-X_b}{X_b}\times 100$$

(3)

where X_a and X_b is mean values of selected individual soil parameters in differently managed soil and in control soil, respectively. The negative value of SDI shows the intensity of soil degradation, and the more negative values correspond to more degraded soils.

Calculation of resistance indices (SRI) indicates the response of selected soil properties to applied management techniques [31]. SRI is standardized by the control in order to taking into account the differences for changes that an applied management could cause, as follows:

$$SRI=\frac{2\left|D_0\right|}{(X_b+\left|D_0\right|)}$$

(4)

where D₀ is the difference between anthropogenically managed soil (X_a) at the end of management and X_b is the control. SRI varies between −1 and +1. SRI with the values +1 indicates the highest resistance probability with no disturbance of applied techniques, and lower values show less resistance to management with the strongest effect of disturbance [31].

2.4. Statistical Analyses

The statistical analysis was performed with SAS Enterprise, version 7.1 (SAS Institute Inc., Cary, NC, USA). In order to identify any differences between the experimental treatments, analysis of variance (one-way ANOVA) was employed. In an attempt to determine the least significant differences at the 0.05 probability level, the means of the treatments were compared using Fisher’s LSD test.

3. Results and Discussion

3.1. Changes of Main Soil Properties under Different Soil Management Techniques

Soil acidity remains the most important chemical constraint on soil fertility and productivity. Acid soils are characterized as unproductive due to the nutrient deficiency, lack of important macronutrients, and harmful effects of some elements [32,33]. Crops grown in acid soils have limited access to water and nutrients due to the roots’ poor water and nutrient uptake, resulting in reduced crop development and yield [34,35]. In such cases, it is very important to assess soil chemistry and acid soil conditions using various soil management techniques.

The data in Figure 2 illustrate how key soil chemical properties responded to management practices. All applied soil management techniques significantly affected soil pH. After application of different techniques, soil pH increased from 4.1 to 5.2–5.9. This result supported the findings of other scientists, who discovered that soil pH is an easily controlled parameter and can be sufficiently modified by different management techniques, especially liming [36,37]. Eidukeviciene et al. [38] observed that long-term liming at a 1.0 rate (liming rate calculated based on the soil hydrolytic acidity) every 3–4 years and every 10 years over a period of two decades in Retisol changed the acid soil’s pH_KCl and exchangeable Al concentration in the whole profile up to 100 cm depth. The low pH of the unlimed soil is related to the lack of carbonates in the parent material or the presence of carbonates, but only in the deeper layers of the Retisol profile (below 200 cm) and the leaching of bases due to the percolation of water in a moderately humid climate [39,40].

The concentration of mobile aluminum decreased along with the decrease in soil acidity. The amount of mobile aluminum decreased twice or more depending on the applied management. This is particularly important because it is the fraction of aluminum that plants tend to take up most effectively. Furthermore, this form is easily leached unless, when environmental conditions change, mobile Al can be reabsorbed into the solid phase in the form of precipitates or complexes or bind to exchange sites. However, different tillage types reduced the amount of aluminum compared to other management techniques. The amount of mobile aluminum decreased from 99.8 mg/kg to 45.1 mg/kg or 36.1 mg/kg, respectively, after the application of deep plowing or shallow plowless tillage. Soil management has a considerable impact on the amount of nutrients (plant-available phosphorus and potassium) in the soil. The greatest increase in soil nutrients was observed after the long-term application of manure and residue incorporation, which increases the bioavailability of nutrient components for plants and microorganisms. Furthermore, it can be attributed to an increased input of plant residues into the soil, which contributes to the development of SOC and thus the total nutrient content of the soil [41]. These data agree with those obtained by other researchers. According to the data of long-term experiments, liming and manure application had significant and positive changes on soil agrochemical properties, including pH, organic carbon, mobile phosphorus, and potassium, when comparing the changes of chemical properties to the control (natural Retisol) [42,43]. Based on the data received, it can be stated that the management of acid soils is crucial in increasing the amount of nutrients in the soil, because in undisturbed, especially naturally acid, low pH soils, most nutrients are “locked” in the soil and unavailable for plants [44].

3.2. Influence of Different Soil Management Practices on SOC Content and Its Transformation Processes in the Topsoil

Conservation of soil organic carbon (SOC) remains essential for sustaining soil, water, and food security as it regulates climate, water storage, supply, and biological activity [45]. Nevertheless, land-use changes, such as agriculture, removing natural vegetation, and expanding soil management, have had considerable effects on SOC [46,47]. The data presented in Figure 3 show the effects of different soil management practices on SOC content. The results show a general trend of increasing SOC after applying manure, residue incorporation, and shallow plowless tillage. SOC content, averaged across all soil management practices, increased in the following order: deep plowing < shallow plowless tillage < residue incorporation < manure. The aforementioned trend coincides with the findings of other researchers [48,49,50]. Liming had a negative effect on SOC accumulation; a significant decrease in SOC content was observed after long-term liming. With respect to the decrease of organic carbon during liming, it is also associated with the destruction of soil aggregates and subsequent release of carbon from them [51]. The additional carbon inputs associated with improved vegetation production from root biomass turnover cannot recover carbon losses. Humification rates of SOC in the soil are slower than mineralization rates. Also, the alkaline pH would favor SOC solubilization and leaching [52,53].

The SOC content in natural Retisol constituted 1.35%, but long-term liming reduced the SOC content by approximately 0.9 percentage points. Based on the data collected, it can be assumed that liming was associated with an increased rate of mineralization, where changes in soil pH can facilitate the bacterial mineralization of both newly formed and pre-existing organic matter. Other scientists have also pointed out that in light clay soils with soil clay concentrations below 20%, the addition of lime can promote the mineralization of SOC [54]. Over the entire study period, 0.12 percentage points more SOC was detected in the shallow plowless tillage, while there was no significant difference in deep plowing. Techniques such as shallow plowless tillage can preserve and/or maintain organic carbon by reducing residue uptake and aggregate breakdown. This is consistent with the observations of Koga and Tsuji [55] that long-term management based on NT prohibits the accumulation of SOC in soil. Manure and residue incorporation showed higher SOC accumulation potential and improved by up to 0.4–0.5% more carbon in the topsoil. The increase in SOC accumulation may be related to the direct input of organic matter, as suggested by other scientists [56,57]. As a result, sufficient fertilization of acid soil can be an efficient strategy to restore ecosystem services; particularly, when the soil is managed sustainably, high levels of carbon sequestration can be promoted [49,56].

The appropriate soil management to maintain soil health and ecosystem services requires knowledge of how SOC responds to land use changes. The growing demand for carbon sequestration has led to an increasing number of attempts to monitor the effects of different soil management practices on SOC dynamics and its transformation processes [58]. Meta-analysis is a valuable statistical approach for assessing qualitative changes in carbon over longer periods of time, comparing the effectiveness of different soil management techniques, and identifying the most effective ways to increase soil carbon sequestration. When assessing the effects of different management practices on relative annual change in SOC, unequal trends were observed. SOC content changed relative to the yearly change in carbon, ranging from −0.49 g kg⁻¹ to 0.47 g kg⁻¹ (Figure 4). Studies conducted by other scientists who investigated the influence of different management techniques on SOC transformation processes [51,52] support the findings of our study. The obtained results can be interpreted as follows: adding organic matter to the soil promotes the fixation of organic matter particles in recently produced microaggregates, which are characterized by greater stability [53].

Incorporation of residues that consist mainly of nitrogenous substances can affect the negative balance of organic carbon accumulation. Since these compounds are quickly mineralized in the soil, humus accumulates more slowly. Nutrient deficiencies in acid soils may have contributed to the mineralization of organic matter and the negative balance of organic carbon accumulation.

The duration of carbon sequestration can be used as an indicator to calculate a different technique’s potential for sequestering carbon (g kg⁻¹). Most studies conducted abroad have shown that the use of different origin organic fertilizers, especially in acid soils, can maximize the carbon storage potential. These actions also promote the removal of carbon from the atmosphere in addition to increasing the carbon content in soil [59,60,61,62,63]. Our study showed that long-term manure application has the highest potential for sequestering carbon (0.36 g kg⁻¹) (Figure 5). This trend could be explained by the fact that the addition of manure to the soil promotes the formation of micro-aggregates in macro-aggregates, while increasing the amount of particulate organic matter [62,64,65].

Evaluating the effects of residue incorporation into natural Retisol, negative values of the carbon sequestration potential (−0.19 g kg⁻¹) were observed. Similar trends were found by other authors, suggesting that residue incorporation may limit SOC sequestration by improving SOC decomposition and reducing carbon sequestration efficiency [66,67,68,69,70]. Residue incorporation and deep plowing showed negative values of SOC sequestration potential (−0.19 g kg⁻¹ and −0.13 g kg⁻¹, respectively), and the loss of C comprises −0.28 g kg⁻¹ and −0.13 g kg⁻¹ per year, when comparing it to the natural Retisol (control).

3.3. Soil Degradation and Resistance Indices of Different Soil Quality Parameters

Soil degradation is a complex mechanism that is often the result of several interrelated processes. Farmers and scientists need to identify the main dominant degradation processes and associated indicators for sustainable soil management. A number of soil parameters are often used as indicators of soil degradation [71]; however, the use of individual soil characteristics often provides an insufficient representation of soil degradation. The inclusion of soil properties in numerical indices has been proposed as a solution to this shortcoming [72].

The soil degradation index was established to determine the state of soil quality and indicate the current state of soil degradation as a threat. The obtained data revealed that the analyzed parameters were significantly influenced by the applied soil management techniques (Figure 6). Total nitrogen was a highly deteriorated soil parameter. This may be due to higher mineralization followed by uptake by plants and loss to soil erosion, which is often when land is cultivated [73]. Available phosphorus and potassium were the second- and third-most deteriorated soil parameters. SOC was the fourth-most affected soil parameter. According to this study, soil pH and mobile aluminum were the least deteriorated soil parameters in terms of degradation index values.

According to the SDI indices, the applied agricultural practices were classified as follows: soil tillage < soil liming < residue incorporation < manuring. Soil tillage and liming have been identified as a measure by which management-induced changes are large enough to increase soil degradation. These agricultural practices have been evaluated for lower decomposition rates, resulting in higher SOC and nutrient levels. Residue incorporation helps to accumulate organic matter and thus improves porosity, aggregation, nutrient supply, and infiltration, and inhibits degradation as a threat. These statements are confirmed by other scientists [74,75,76]. A higher level of degradation risk was observed by Nascimento et al. [77] in soils characterized by low SOC levels. Other scientists have also found a trend in which higher degradation potential was observed in those soils where liming and tillage were applied without the insertion of additional organic material [78,79].

Calculation of soil resistance indices (SRI) revealed that tillage showed a weaker effect in managing soil quality parameters. Positive SRI values indicate the highest probability of resistance without interfering with applied techniques, while negative values indicate lower resistance to management with the strongest effect of disturbance [80,81]. The lowest values of soil resistance indices were obtained for mobile aluminum, organic carbon, and pH in all applied land management techniques, which means that these soil parameters were most influenced by applied management techniques (Figure 7). Soil nutrients showed the greatest resistance to applied management techniques.

The calculated SRI values showed that all analyzed management techniques had a similar effect on soil quality parameters, especially SOC, pH, and aluminum. This is in line with the findings of Raiesi and Beheshti [82], who suggested that these properties are more sensitive to management and land use changes compared to others.

4. Conclusions

In terms of soil quality and health determinants, the applied agricultural practices were categorized as follows: manuring > residue management > reduced tillage > liming. The obtained results showed that soil fertilized with manure had higher soil quality parameters such as organic matter, total nitrogen and available phosphorus and potassium. The evaluation of the relative annual change in SOC content revealed that long-term soil manuring has a high potential for SOC sequestration. Among the soil management techniques examined, the greatest relative annual change in SOC content was observed with manure. This proved to be the most suitable method for the acid soil of Lithuania, considering the SOC sequestration potential. The lowest values of soil resistance indices values were obtained at low levels of nutrients, organic carbon, and pH, indicating that these properties are more sensitive to applied agricultural practices compared to others. Overall, the studies performed provide a comprehensive quantitative and qualitative assessment of the effects of various methods of management on SOC content and other parameters, which could help to better understand the response of soil quality to agricultural management practices and provide evidence to support acid soil conservation. Further research is needed to evaluate key soil assessment indicators that provide a clearer and more accurate picture of how acid soils are acting, which helps to decide what preventive measures should be taken to maintain soil sustainability.