Assessment of Soil Sustainability Using the LUCAS Database in the Southwest Region of Romania

Abstract

To ensure soil sustainability, the European Union considers the mitigation of the ecological, social and economic impacts and the prevention of soil degradation, which is the primary source of the ecosystem. In this respect, Land Use and Coverage Area Frame Survey (LUCAS) studies aim to investigate land use at the community level to gather information necessary for the analysis of the interactions between agriculture, environment and rural landscape and to provide estimates of agricultural areas with main crops. According to data from Eurostat, between May and October 2022, through the use of digital techniques, the levels of land coverage and land use, pastures, as well as irrigation management and structural elements in the landscape, were examined on the ground throughout the European Union. Data on the agricultural environment and soil were collected in the georeferenced points belonging to a representative sample by observing and completing the field form. At the level of the southwest region of Romania, the study was based on the inspection of 274 points by taking soil samples to analyze the quality indicators and identify key species of flowering plants. Data on land coverage and use can be used for a variety of environmental and socioeconomic projects in different fields.

1. Introduction

Starting from the premise that soil is a non-renewable resource, a complex environmental factor and support for life and that its formation is an extremely slow process [1,2,3,4,5], the assessment of soil quality at the EU level is presented in the Environment Action Program [6]. The European Union’s thematic strategy for soil presents the need for sustainable soil use and the EU’s commitment to:

• Reduce soil erosion;
• Increase the content of organic matter in the soil;
• Limit the effects of anthropogenic pressures on the soil;
• Manage the land in a sustainable way;
• Remedy contaminated soils.

The European Commission’s communication on the Thematic Strategy for Soil Protection (COM (2006) 231) outlined the plan for the EU to commit to a high level of soil protection with the aim of protecting soil functions and of preventing further soil degradation [7]. Within this framework, the Member States of the European Union decide how to promote sustainable soil development, and the European Commission presents the economic, social and environmental impact assessment [8,9,10,11,12,13,14].

According to Decision No 1445/2000/EC of the European Parliament and Council of 22 May 2000 on the application of aerocartography and teledetection techniques to the production of agricultural statistics from 1999 to 2003 [15,16,17], Decision No 2066/2003/EC of 10 November 2003 [18] and Decision No 786/2004/EC of 21 April 2004 [19], the draft Community land use survey in the field of agricultural statistics was implemented, called the LUCAS project.

Given that agricultural land accounts for approximately 50% of the EU surface, agriculture is closely related to soil health. Because the soil is subject to erosion challenges, desertification decreases in organic matter content, loss of biodiversity, subsidence (due to intensive agricultural practices and monocultures), pollution with chemical substances (pesticides, heavy metals, phytopharmaceuticals, and plastics), at the level of the European Union, the LUCAS database is used for strategies, priorities, and actions to ensure soil sustainability and develop organic productions.

The objective of the LUCAS project is to test the feasibility of a land use survey system at the Community level, to gather information necessary for the implementation and monitoring of the common agricultural policy, to analyze the interactions between agriculture, environment and rural landscapes, and to provide estimates of agricultural areas with main crops. In this regard, the objective of the study is to create a database that provides information on the quality of the lands from an agrometeorological point of view, agricultural crop monitoring, and production forecasting at the level of the European Union. Thereby, it provides harmonized information at the EU level for the use and coverage of agricultural land and for the environment [20,21,22].

The LUCAS studies were carried out in the periods of 2001–2003 and 2005–2007 for the following Member States: Belgium and Luxembourg, Czech Republic, Denmark, Greece, Spain, France, Italy, Latvia, Lithuania, Hungary, The Netherlands, Austria, Poland, Portugal, the Slovak Republic, Finland, Sweden, the United Kingdom and Ireland, Estonia, Hungary and Slovenia.

Land use studies were conducted in two phases (spring and autumn) for about 100,000 observation points. In 2004, a sample design methodology based on the EU grid was defined in line with the INSPIRE recommendations. Thus, in 2006, 169,197 points were observed, and it was necessary to stratify the points in the basic sample using the photo-interpretation method in the 2 km grid covering the EU-25 territory in 2005. The survey focused on agricultural areas and had a sampling rate of 50% for arable and permanent crops and 40% for pasture. Based on this methodology, the parameters at the level of each georeferenced survey point on the field were analyzed using GPS technology, orthophotographs and maps to locate and reach points on the field. In the spring of 2007, another LUCAS study was conducted, focusing on environmental variables (risk of erosion, irrigation, landscape characteristics) and soil sampling. In 2008, a study was conducted in Bulgaria and Romania as part of the PHARE 2006 Programme, and in 2009 and 2012, LUCAS triennial studies were conducted, covering the whole territory of the European Union [20,23,24,25,26].

The results analysis studies were based on agri-environmental indicators regarding the potential of aerial photo-interpretation for data collection for the use of photographs for landscape classification, on the future preparation work of the LUCAS program, and technological surveillance in order to improve the data collection process.

The 2001–2003 survey, conducted in the EU-15, includes land cover and use and environmental parameters (linear elements along transects, erosion, noise and risks). Data from the period 2001–2007 allow for the analysis of the time series for monitoring the common agricultural policy within the limits of restrictions due to the change of methodology and the limited coverage of data samples [26,27]. The field survey from March to September 2015 was based on 273,500 points [28], and the 2018 survey was based on 337,854 points, of which 238,077 were in the field, and 99,777 were photo-interpreted [29].

The landscapes were evaluated along a 250 m transect where land coverage transitions and linear features were recorded. The structures of EU landscapes were analyzed by taking into account the following elements: richness (number of different types of soil cover), diversity (relative abundance of soil cover types) and fragmentation (presence of structural and dissection elements, to provide information on the spatial organization, presence and arrangement of the landscape features. In the studies of 2009, 2012 and 2015, there were also recorded transitions of land cover along the transect (250 m walk from each field sample to the east). From the data of the transect, the Shannon uniformity index was calculated, which provides a measure of the diversity of the landscape. In 2012, for the EU-27, the Shannon index was 0.7 [30,31,32].

The Shannon Evenness Index (SEI) can be used to assess landscape diversity and takes into account the number of different types of soil cover and their relative abundance (the index has values in the range 0–1.0 representing a landscape without diversity—only one type of land coverage, and 1 representing maximum diversity—all types of land coverage in equal shares). If a landscape is characterized by different types of soil cover found in equal shares, then the Shannon uniformity index tends to be 1, and if there is only one dominant type of land cover, the index tends to be 0 [33].

$$SEI=-\sum _i^m\left(Pi\ast ln\left(Pi\right)\right)/\mathrm{l}\mathrm{n}\left(m\right)$$

(1)

where Pi = relative abundance of types of land cover and m = different types of land cover.

A landscape mapping at the level of the European Union in 2012 emphasizes the existence of soil diversity and provides information on the differences and similarities between EU countries; thus they are:

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Mountainous or hilly areas, which register a value of over 0.75 on the Shannon uniformity index (Austria, Luxembourg, Slovenia and Portugal);

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Areas with a landscape diversity similar to the EU average (Poland, France and Germany);

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Areas with a low degree of diversity and mostly covered by forests (Finland, Estonia);

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Areas with a low degree of diversity (indexes less than 0.65) and a land cover type of grassland, cultivated land or abandoned agricultural land (Ireland, Hungary, Romania or the United Kingdom) (Figure 1) [31,33].

Multiple factors influence soil degradation, with their actions leading to an average soil erosion rate of 2.46 t/ha/year. Soil rehabilitation through organic matter and soil organisms that can combat soil erosion depends on the formation of soil structure. In this respect, the soil is an essential agricultural resource of prime interest for the common agricultural policy, the LUCAS studies from 2009, 2015, and 2018 have as a base the soil sampling and analysis of soil quality by determining the organic carbon content and the quality indicators: texture, structure and permeability, which contributed to the assessment of soil erosion (Figure 2) [34,35,36,37,38,39,40].

Pastures play a fundamental role in animal feeding and provide important ecosystem services (erosion control, water management, biodiversity, crop services and carbon stock protection). Information on the extension, typology and management of land for grazing is essential for the nutrient balance and for the calculations on agri-environmental aspects of the CAP (Common Agricultural Policy). The integration of in situ LUCAS data and Copernicus teledetection maps provide detailed thematic and spatial information for grazing grounds. The area estimates for each country are based on modern regression methods, using LUCAS and Copernicus in situ data (Figure 3) [41,42,43,44,45].

2. Materials and Methods

The sample study is carried out in two phases: the systematic or basic sample is linked to the 1 km grid and corresponds to approximately four million observation points for the whole European Union. The first phase sample is a subgroup of the basic sample, which corresponds to the 2 km grid, meaning points spaced at 2 km in the four cardinal directions and covers the whole EU territory, so it includes about 1.1 million different points. Each point in the basic sample is photo-interpreted, and it is incorporated in one of the seven predefined land cover categories (arable land, permanent crops, permanent pastures, forestry, shrubland, empty or low/rare vegetation land, water, or artificial land). A subsample, called a field sample, shall be extracted from the basic stratified sample to be classified following the field visit according to the established nomenclature [15,22,23,24,46,47].

2.1. Subsection Equipment and Software Used

According to the EUROSTAT data (the statistics office of the European Union), between May and October 2022, the levels of land coverage and use, pasture, as well as irrigation management and structural elements in the landscape were examined on the ground using digital techniques throughout the European Union. For Romania, the study covered 7867 points found on all types of soil cover (cultivated land, pasture, forest, urban, and transport networks). Out of the 7867 points on the Romanian territory, soil samples were collected from 1614 points, and the quality physicochemical indicators were analyzed to use these results in the assessment of the quality of environmental factors, to update the European soil maps, validate soil patterns, and measure the amount of organic carbon in the soil—an important factor in climate change analysis. The study occurred in the field and was carried out in its current form every 3 years, between 2009 and 2018, and also in 2022, 4 years after the last study [15,20,26,27,48,49,50,51].

LUCAS’ objective to collect data on land cover and land use and on the agricultural and soil environment by observing the field of geographical reference points, completing the field form, taking photographs and taking soil samples is based on data storage in the Data Management Tool (DMT) [50,52].

The quality control workflow can include up to five levels of control (Inspector, Supervisor, Central Office, External Quality Control, and Eurostat). At each step, the data is checked qualitatively before being redirected to the next specialist by an external company, for 40% of points, with automatic and manual controls being applied. The main manual controls consisted of checking whether the data was in accordance with LUCAS’ instructions and rules; ensuring no formal errors and obvious content errors were present; comparing the data; checking the transect; checking the GPS tracks; and checking the quality of the photos [50,51,52].

The LUCAS data collection process is intended to collect raw microdata (e.g., tabular data, images, and GPS tracks) at the georeferenced points belonging to a representative sample. The volume of these data sets is considerable and requires specific tools for managing transmission, editing, and storing. Due to these specificities, the standardization and computerization of the LUCAS data production process phases were consolidated in 2008 and 2009, and an ad hoc IT tool called the Data Management Tool (DMT) was developed [20,22,23,24,25,26,27]. A very important IT technology innovation introduced in 2008 is the Data Management Tool, which provides support in all phases of the survey with the following main modules:

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Point management: data input tool (supervised input of data, consistency and intervals verification);

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Data import (sent forward one level below or sent back one level above);

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Data export;

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Allocation of points;

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Report generator;

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Choice of language.

The data entry module is supervised and reproduces the field form for field data recording. The topography is guided in data editing, indicating the next field to be filled in and modalities that are consistent with those already entered. Includes a list of online ranges, consistency checks, and automatic controls. If editing data and the rules are violated, DMT provides a warning message informing about the problem. These checks are carried out while importing or exporting data. The data workflow between different actors managed by DMT is shown in Figure 4 [53].

The LUCAS 2022 study is coordinated by the Statistical Office of the European Commission (Eurostat) and contains the following sections [20,26,43,54]:

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Basic (includes the extensive grassland; includes point identification, land cover and land use issues, land and water management, habitat and pasture assessment issues, extended to 40,000 points);

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With a specific module on the ground (Soil Module, takes place in 41,000 points; a surface soil sample is collected by standard procedure, using a spade or by sample collection procedure, to measure density in bulk at 4000 points; a sample for soil biodiversity is collected for 2000 points);

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With a specific grassland mode (PASTURE module rated for 20,000 points);

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With a specific mode on landscape characteristics (Landscape Features module LF, for the assessment of the agricultural landscape);

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With a specific module on Copernicus (Copernicus Module).

The collected data are used to compile statistical tables on land coverage and use, model agri-environment aspects and are used as ground control for satellite images [20,26,27,43].

Equipment and software for the basic LUCAS used in the field require the following items:

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The land document (GD) is the basis for locating the point and estimating the area of the plot on which the point is located. It also includes an inspector map with a scale between 1:10,000 and 1:200,000 and the orthophotoplane (an orthorectified aerial photograph, without any distortions caused by relief and/or inclination angle, with a scale that varies between 1:10,000 and 1:2000) (Figure 5) [52,53,54].

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The LUCAS PLOP application was used to directly upload data taken from the field to the DMT server [53].

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The Locus Map and Mobile Topographer applications have been used to reach and prove the research of the LUCAS point by registering the route track and loading it into DMT (Figure 6) [53,55].

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Google Earth and Global Mapper apps were used to plan the car route to the LUCAS points (Figure 7).

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Photographic apparatus/mobile phone—Landscape photographs in the four cardinal directions were taken at the point reached in the field, and where the point could be seen, the point photograph was taken (Figure 8). The other photographs were taken to identify the land cover, the presence or absence of water management, the need to collect a soil sample and the need to document conflict cases. All photos were taken with the orientation of the phone in view mode [20,26,27,43].

2.2. LUCAS Point Mapping Methodology

Preparatory work is essential for an efficient study to be recommended for use: GPS, updated maps to identify the most accessible access routes to the point, daily route planning using small-scale inspection maps (Figure 9), planning the order of the points to be visited on the same day, identifying the optimal route, quickly analyzing the orthophotoplane, and additional point search on the free Earth observation program Google Earth or Google Maps.

2.3. Access and the Exact Location of the LUCAS Point

The step-by-step form is completed in the field after documenting the observations by means of several photos and relevant information regarding the location of the point: GPS coordinate system, accuracy, altitude, point coordinates and distance to the point. DMT will automatically calculate the exact point on the ground according to the GPS coordinates. In the context of mapping activities of Earth observations, LUCAS microdata and photographs are used for the production, verification, and validation of the processes (Figure 10) [50,53,54,56,57,58].

Close to the point location, the larger-scale surveying map can be used, along with the orthophotopoplane and the photos from the past study. The points are marked on the orthophotoplane and on the inspection map by a specific sign, that is, the intersection of two lines representing a cross. To locate a point, priority is given to the fixed and then to the uncertain landmarks (parcel boundaries). The exact location of the point can be identified by the simultaneous use of GPS, compass, orthophotoplane, and inspection map (Figure 11).

2.4. The LUCAS Point Research

In cases of point visibility, the approximate distance to the point must be noted (less than or more than 100 m) by checking the relevant box on the field form. If access difficulty to the point and the distance are >50 m, this should be recorded. LUCAS is an onsite study, and the points must be visited in the field. Onsite photo-interpretation is only used when the point is not visible from the closest accessible location. Spot photointerpretation is allowed in the following cases: the point is located in water or in an inaccessible wet area; dense vegetation obstructs all the possible access points (dense shrubs, thorns, and impassable forest); the area surrounded by signs of access forbidden or with inaccessible fence (forbidden area); private areas fenced or surrounded by walls (company premises, private gardens) [50,53,54].

2.5. Land Coverage and Land Use

The classifications used in LUCAS are comparable to other statistical standards, which are similar to those included in the EU FSS farm structure survey, those adopted by the FAO (United Nations Food and Agriculture Organisation), or by the European Nature Information System EUNIS for the classification of forest types and areas.

According to Eurostat classification, field coverage takes into account eight categories, 29 classes and 76 subclasses, while land use includes four main categories, 16 classes and 31 subclasses [27,29].

A point has no width or length and corresponds to a circle with a radius of 1.5 m (diameter 3 m), representing an area of 7 m², which falls into a homogeneous area (arable land, upper part of a house) [15,20,21,22,44,45,50].

When the land coverage is heterogeneous (consisting of trees or grass blended shrubs) and unclassifiable, the observation scale has to be modified, in the sense of a systematic environment observation in the adjacency of the point, which is conceptualized as the extended observation window. The extended observation window stretches from the point to a distance of 20 m (diameter 40 m) (representing an area of 0.13 ha) (Figure 12) [29,41,44,45,50,51].

The observation window shall be extended when the coverage of the ground at the point is non-homogeneous, that is, it appears systematically in the following areas: permanent crops, forest area, shrubland, pasture, empty land, and wet area (Figure 13) [20,21,22,29,48,50,51].

The above orthophotopoplane shows a non-homogeneous area with grazing area and fruit trees, for which the extended observation window must be applied. If the extended observation window is applied, the land coverage within the boundaries of the plot where the point is located shall be observed, and the extended window and the homogeneous plot within it shall be noted (the extended window covers the maximum area in the circle with a radius of 20 m with the same coverage and use of the terrain) (Figure 14) [20,21,22,41,44,45,47,48].

At the point, the coverage is a wooded area, so observation must be made within the extended window, which must be extended only within the plot defined by the boundary of the forested area and the pasture area, not including the area inside the pasture (which is a different plot). The density of trees and shrubs is to be assessed in the hash part of the circle to decide whether it is shrubland or a wooded area and whether it is coniferous, deciduous, or mixed, and what type of forest it is (Figure 15).

2.6. Analysis of Land Coverage

Land cover (LC) is the biophysical coverage of the land (crops, grass, coniferous/deciduous forest or built areas). LC is recorded for each point in accordance with the LUCAS reference document C3—Classification. One or two field coverages must be recorded for each point. The dominant soil coverage is recorded as the first land coverage (LC1). When more than one ground cover coexists in the same area, a second ground cover may be required to describe the point.

Land cover classification examples: artificial land, built areas or covered buildings separated into three categories ≤3 floors or less than 10 m high, >3 floors or higher than 10 m, greenhouses), and unbuilt areas (with artificial cover) [27,28,29,59].

2.7. Analysis of Land Use

Land use signifies the socioeconomic ground utilization (agriculture, forestry, leisure or residential use). In order to determine the primary use of the land, it is significant to evaluate the context and determine whether the area under consideration is integrated into an adjacent area that determines its use. Examples of land use classification: parking, building > 10 m, road > 3 m, road < 3 m, agricultural road, closed roads, open roads and parking lots, roads not closed with only a certain vegetation, greenhouse, small buildings, bridges and other overlapping elements, power lines [27,28,29,54].

Cultivated land means there is plant production on a land plot (cultivated land, the crop has not yet appeared in a plowed and sown field, crop already harvested that is identifiable by plant residues, crop already harvested that is not identifiable by plant residues, species inclusion of plants, mixed crops, a mixture of two cereals, mixtures of more than two cereals, uncovered areas between the rows of an orchard, grassy areas between the rows of a vineyard, fruit trees in vegetable gardens, isolated fruit trees, chestnuts, cherries, walnuts and other fruit-bearing trees, and abandoned crop areas) [27,28,29,54,59,60].

Forest area is related to forest areas, with at least 10% crown-covered extended observation window. When mixing deciduous and coniferous trees, a criterion specifying the area should be 75%, or more, covered with the crowns of a group has to be taken into account. Otherwise, the forest is considered mixed [27,28,29,54].

The shrubland zone is dominated by more than 10% of the area of shrubs and small woody plants (hedges, grazing on the shrub zone, shrubland zone with trees, and pasture zone) [27,28,29,41,44].

Bare and lichen/moss land includes areas covered with lichen or moss or covered with very little vegetation (at least 90% of the land or more is bare) (these must cover more than 10% of the land but cannot be present other vegetation with a density higher than 10% (culture has not yet appeared, uncultivated land) [54].

Water zones include vegetation-less inland or coastal areas covered by water, as well as zones that are flooded most of the year. The course of the inland running water is determined by the average water level. Lakes are permanent water reservoirs, while the islands within are to be included in the land area. Aquatic areas are vegetation-less territories covered by water and flooded surfaces.

Wetlands are areas included between land and water, which are humid for enough time so that the flora and fauna that live in the vicinity have adapted and are dependent on wet conditions for at least a part of their life cycle. Wetlands are considered lands that are temporarily or permanently flooded with water, slightly moving or standing, and can be shallow, fresh, brackish, or saline [20,21,22,27,28,29,44,45].

3. Results and Discussions on the LUCAS Study

LUCAS provides information on agricultural areas, land cover and land use, urban data, forest data across the EU. Accuracy is approximately 2% for the main categories of wheat, cereals, arable land, permanent pastures, permanent crops, forests, urban areas, and inland waters. Soil sampling and analysis results are strongly influenced by the weather conditions and the agricultural season stage. With the help of the GPS technology (photos, maps, and orthophotographs), it was possible to relocate on the field in 2007, and all the points were correctly investigated in 2006 [15,20,21,22,29,41,42,43,44,45,47,48,50,51].

LUCAS is the leading provider of the in situ data required for GMES (Global Monitoring for Environment and Security). In order to support satellite research, in situ data at EU-27 level are needed for the space activities programs under the Seventh Framework Program for Research and Development. The CORINE operation uses LUCAS data and photographs [61]. LUCAS is a land management information system that provides information on land coverage and land use in a consistent manner throughout the European Union, making it the basis of the future European Space data infrastructure (IEDS). The results of modelling and teledetection methods cannot replace in situ or onsite monitoring by LUCAS, which is defined as one of the European in situ standards under the INSPIRE initiative [20,21,22,41,44,47,48].

Following the inspection of the 274 LUCAS points in the Southwest Oltenia region, Romania, the following were identified and located: 75 points in forest land, 7 points in wetlands, 42 points in cultivated land, 18 points in artificial land (roads and human settlements), 36 points in shrubland, and 96 points in pasture (Figure 16) [55].

Compared to the methodology for identifying land cover and land use in 2018, new submodules for the SOIL module were introduced in 2022 [22,26,29,44,50,54,55]:

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Standard five-point soil sampling (four samples from the cardinal directions N, W, S, and E and one sample from the LUCAS point) to determine the content of N, P, and K (only one sampling was carried out in 2018 from the LUCAS point) (Figure 17);

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Soil samples for determining bulk density (sample bulk), using metal cylinders with a diameter of 7 cm and a height of 5 cm; the sampled soil was weighed, the value being recorded in the field form;

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Sampling to determine soil biodiversity and humus content; the samples were taken with a spade from all five points at a depth of 30 cm (soil bulk sample) and on the 0–10 cm, 10–20 cm, and 20–30 cm depth levels, forming a composite sample to determine the biodiversity. The soil samples collected from the three depth sections were labelled and maintained for a maximum of 15 days at a temperature of 5–10 °C in a freezer.

For route planning, the three types of soil samples were marked differently on the LUCAS points map (Figure 18).

The PASTURE module was supplemented in 2022 with the submodule for identifying key species of flowering plants and determining their density from a section (transect) of 100 or 200 m² (10 m wide and 20 m length) between 15 May and 15 June until the hay harvest phase (Figure 19).

The specimens of the key flowering plant species identified in the 200 m² transect were sampled from the following botanical families: Apiaceae, Campanula, Centaurea, Cirsium, Juncus, Myosotis, Orchidaceae, Scabiosa, Silene, Trifolium, and Vicia.

For Copernicus modules, landscape analysis, land cover and land use analysis, the LUCAS points research methodology in 2022 was no different from the one used in 2018 [22,26,29,44,50,54].

Land coverage and land use data can be employed for multiple environmental and socioeconomic projects related to different areas [62,63,64,65,66,67]:

• Assessment of the agriculture impact on the environment through the agri-environment indicators (AEI) for organic matter and soil erosion, as well as indicators of the degree of artificiality, and landscape structure within the integration of environmental concerns into the Common Agricultural Policy (CAP) post-2013, which are related to the European Commission Directorate-General for Agriculture and Rural Development.
• Resource efficiency indicators and soil protection, which are related to the European Commission Directorate-General for Environment.
• Climate change analysis as part of the European Climate Change Program, which is related to the European Commission Directorate-General for Climate Action.
• Production, verification, and validation processes related to the datasets describing the main types of soil cover, which are derived from satellite images, according to the Copernicus observation program. These are related to the European Commission Directorate General for Internal Market, Industry, Entrepreneurship and SMEs.
• The core set of indicators (CSI), climate change indicators (CLIM) and Streamlining European Biodiversity Indicators (SEBI), which are related to the European Environment Agency.
• Land use, land-use change, and forestry (LULUCF) in relation to greenhouse gas emissions reduction, which are related to European Commission Directorate-General for Climate Action.
• The data obtained can be useful for the following objectives:
• Gathering information on agriculture and environment (estimates of cultivated land, agri-environmental indicators on landscape and changes in land coverage, presence of linear characteristics and landscape diversity across Europe, basic information to shape the erosion risk, for conducting surveys on irrigation use and mapping landscape elements);
• Landscape analysis;
• Earth observation;
• Sound methodology, harmonized at the EU level, proposes two sampling phases of non-grouped points, with stratification after the first phase;
• Volume of data and photos used to measure changes in land use and land coverage over time;
• Operational IT infrastructure (hardware systems, data center, a software system for data collection, checking them by comparing with photos and their quality control, for sample creation, for calculating estimates and for recognizing the diversity of landscapes in photos, and for comparing different grids used in the land use surveys);
• Strong experience in the management of land use surveys.

4. Conclusions

The interactions between agriculture, environment, and rural environment can be studied by assessing the changes that take place over time in terms of land coverage and land use of the territory and along the drawn transits, but also by analyzing the environmental parameters under investigation (landscape recognition, risk of erosion, and structural and linear elements).

The European Commission Communication on the Thematic Strategy for Soil Protection (COM (2006) 231) outlined the plan by which the European Union is committed to a high level of soil protection and soil degradation prevention.

Obtaining information at the EU level for the land use and land coverage of agricultural land and for the environment was done by analyzing the parameters at the level of each georeferenced survey point on the field, using GPS technology, orthophotographs, and maps.

The LUCAS study is based on statistical calculations and provides data for the long-term monitoring of agricultural and environmental issues on a European scale. In combination with the orthophotographs and the teledetection data, it provides a better knowledge of the spatial organization of agriculture and the balance between agriculture/nature conservation/cultural heritage/green spaces, which allows us to understand the size, location, connectivity and fragmentation of habitats, thus contributing to landscape conservation and management.

Since the factors causing soil degradation at the EU level are water or wind erosion, the decreasing organic matter content and biodiversity quality, and since the soil is an essential agricultural resource and of prime interest to the common agricultural policy, LUCAS studies are based on soil sampling and analysis of soil quality by determining the organic carbon content and quality indicators (texture, structure and permeability), which contribute to the assessment of soil erosion.

Furthermore, the pastures play a fundamental role in animal feeding and provide important ecosystem services (erosion control, water management, biodiversity protection, crop services and carbon stock), and the information on the expansion, typology and management of land for pasture is essential for the balance of nutrients and for the calculation of agri-environmental aspects for the CAP (Common Agricultural Policy). The integration of LUCAS in situ data and Copernicus teledetection maps provides detailed thematic and spatial information for pastures.

The LUCAS 2022 study was coordinated by the Statistical Office of the European Commission (Eurostat) and contains the following parts, with specific modules for basic, soil, pasture, landscape features, and Copernicus. Compared to the methodology for identifying land cover and land use in 2018, new submodules for the SOIL module and PASTURE module were introduced in 2022. With the help of the basic LUCAS software used in the field (LUCAS PLOP, Mobile Topographer, Locus Map, Global Mapper, and Google Earth) and by applying the LUCAS point mapping methodology (which includes preparatory work, point access, precise point location, point research and site coverage and use), data were also collected for the Southwest Oltenia region, Romania, used to compile statistical tables on land coverage and land use, to model agri-environment aspects and to control the soil for satellite images.

The study is limiting and could be made more complex by determining the state of soil fertility, determining the humus content, the main (N, P, and K) and secondary (Ca, Mg, and S) macronutrients, but also through its microbiological analysis. Thus, the granting of credit ratings for each monitored land suitability for certain types of crops, the fact would lead to obtaining qualitative and quantitative productions.