Economic and Environmental Assessment of Organic Lemon Cultivation: The Case of Southeastern Spain

Abstract

Spain is the world’s leading producer of organic fresh lemons, with production concentrated in the southeast. Given the relevance of this region in lemon production and the role of organic agriculture in sustainable development, this study establishes the main organic lemon production models in Southeastern Spain (Fino and Verna) and evaluates them from the economic and environmental perspective using life cycle costing (LCC) and life cycle assessment (LCA). Both models present a similar cost structure, with labor and fertilization being the most significant costs. Verna presents higher unit cost due to lower productivity. Organic management entails higher unit costs than conventional due to lower productivity and the higher costs of organic fertilization and biotechnological pest control. In LCA, the contributions of the components to the impacts of the organic models are very similar, due to the similarities in the production models. These contributions also resemble those in conventional management systems, with fertilizers being the largest contributor to impacts. Organic systems generally show lower absolute values than conventional, mainly because of the use of organic fertilizers. Fino shows lower values than Verna, driven by higher productivity. The global warming results showed relatively low emissions, 0.053 and 0.068 kg CO₂ eq·kg⁻¹ for Fino and Verna, respectively. Additionally, a sensitivity analysis was performed, introducing variability in non-fresh marketable yields and considering the avoidance of synthetic fertilizers.

1. Introduction

Humanity’s greatest challenge is feeding a growing population in the context of limited agricultural land and increasingly degraded soils. Furthermore, food security is already threatened by climate change and the impacts of intensive agriculture [1]. The intensive agricultural production model involves environmental pressures that lead to soil, air, and water pollution, and the overexploitation of natural resources [2,3]. Faced with this problem, several authors highlight the need to implement organic agricultural practices that guarantee profitability and minimize environmental impact [1,4,5].

Organic farming provides numerous benefits, such as increased organic matter content in soil, improving its structure [4,6,7,8,9,10]. It also increases soil water retention capacity and carbon sequestration, as well as protecting against erosion [9,11,12]. According to Goh [4], due to increases in organic matter, organically managed soils are better aerated, which reduces denitrification and, consequently, the release of nitrous oxide. Benoit et al. [13] demonstrated, in an experiment with herbaceous crops, that organic systems emit 30% or 12% less nitrous oxide than conventional ones, depending on whether the results are expressed per unit of surface area or mass (kilogram of product). Likewise, a recent study by Bocean [14] showed that organic agriculture practiced in Europe significantly reduces greenhouse gas emissions, making it a key tool for mitigating climate change. Biological control (a crucial instrument in organic farming) uses natural enemies to control pests, reducing dependence on chemical pesticides. This not only decreases environmental impacts but also contributes to the preservation of and increase in biodiversity. In their study, Bengtsson et al. [15] found that organic farms host on average 30% more species than conventional ones. According to Calabro and Vieri [12], the protection of biodiversity in organic agriculture is attributed to a greater presence of plant and animal species, and to specific effects such as greater protection of pollinators [16,17,18,19].

However, despite its positive effects, organic farming generally has lower productivity and production stability compared to conventional agriculture (although there are particularities according to the crop and region) [12,20,21]. As a result, organic systems are not always superior to conventional ones in terms of life cycle assessment (LCA), especially when the environmental impact is measured per unit of mass produced rather than per unit of cultivated area [21]. On the other hand, if the results are expressed only per unit of area, it is important to highlight that organic farming requires more land to produce the same amount as conventional agriculture [20]. Therefore, as pointed out in the meta-analysis by Tuomisto et al. [22], it is crucial that environmental assessments take these aspects into account. In economic terms, the lower yield of organic farming must be offset by a higher selling price for the activity to be profitable. Furthermore, the costs of liquid organic fertilizers for fertigation are even higher than those of synthetic fertilizers, and pest control can be more complex due to the limited availability of effective products. Therefore, economic evaluations are essential for the analysis of the viability and profitability of organic production systems.

At the consumer level, organic products are viewed positively by an increasing proportion of consumers, who consider them to be of higher quality due to the absence of synthetic chemicals [6,23,24]. This trend is verified by the sustained increase in the consumption of organic products, especially in Western markets such as the United States, Canada, and Europe [6,25,26,27]. Spain occupies a prominent place in this context, ranking among the top 10 countries in the world with the largest area dedicated to organic farming. According to data from the Ministry of Agriculture, Fisheries, and Food [28], in 2023 organic crop production represented 12.51% of the country’s utilized agricultural area (UAA), a figure that has increased year after year. This sustained growth in the sector makes Spain a key player in meeting the objectives of the European Green Deal. As García Castellanos et al. [29] pointed out, lemon is one of the main agri-food products of the EU. Spain is the world’s leading producer and exporter of fresh lemons and also leads the area and production of organic fresh lemons, accounting for 41% of the world’s area of this crop (data of the year 2023 accessed on 24 April 2025: https://www.ailimpo.com/, accessed on 24 April 2025). Spanish lemon production, both conventional and organic, is mainly concentrated in southeastern (SE) Spain: Almería, Murcia, and Alicante [29].

Environmental issues and market demand for environmentally friendly products are driving public policies in the transition toward more sustainable economies [30]. In Europe, the Green Deal has established the legislative framework to achieve this goal, and the Farm to Fork Strategy is the tool contemplated to promote sustainability in the agri-food sector [31]. This strategy has set ambitious challenges, such as reducing pesticide use by 50%, reducing fertilizer use by 20%, and achieving 25% organic land area by 2030, while also seeking to guarantee greater transparency in labeling and a decent income for farmers [32]. To achieve the organic farming goal, the European Commission implemented a specific action plan for the development of organic production and issued Regulation 2018/848 on the production and labeling of organic products [33]. Likewise, the new CAP (2023–2027) offers financial support to encourage organic farming through measures such as eco-regimes or direct support for organic farming. At the national level in Spain, the Agri-Food Chain Law (Law 16/2021 that modifies Law 12/2013) reinforces the importance of production costs to guarantee a fair market and fair conditions for producers [31,34].

Given the importance of the lemon sector in SE Spain, the edaphoclimatic peculiarities of this region [29], the impact that agriculture has on the environment, and the importance that organic agriculture is gaining as a key to sustainable development, it is of interest to evaluate the sustainability of the organic lemon production models characteristic of SE Spain. To this end, reliable and internationally consolidated economic and environmental analysis methods are needed, such as life cycle costing (LCC) and LCA. LCA is an environmental assessment methodology that studies the entire life cycle of any product, production process, or service, identifying the potential environmental impacts derived from it. Additionally, it enables the identification of the system components that contribute most significantly to these impacts. Thereby, it supports process optimization from an environmental perspective. On the other hand, LCC studies the life cycle costs of any product, production process, or service, and should be carried out from the perspective of an actor within the production chain. LCA is a standardized methodology [35,36], which supports numerous policies [37,38,39], while LCC is recognized as the most widely used economic analysis methodology along with LCA [37]. Both methodologies have been extensively used in the evaluation of agri-food products [37,40,41,42,43,44] and also in the specific case of lemons [29,45,46,47].

Thus, the objectives of this work are as follows:

(1) To establish the most representative organic lemon cultivation models in SE Spain, corresponding to the two most common varieties: Fino and Verna. (2) To apply LCC and LCA to the two production models, to evaluate and compare them economically and environmentally with each other and with the conventional lemon cultivation models described and evaluated by García Castellanos et al. [29]. (3) To conduct a sensitivity analysis, assigning variability to non-fresh marketable yields and considering the avoidance of synthetic fertilizers, as these factors have been identified as relevant in the previous analysis.

This study is supported by the citrus sector through the Spanish Interprofessional Lemon and Grapefruit Association (AILIMPO), which requires scientific evidence for key decision-making focused on a more sustainable management of lemon production systems in Spain.

2. Materials and Methods

2.1. Primary Information

This work follows the same procedure as that of García Castellanos et al. [29]. The data required to establish the production models were obtained under a contract signed between the Spanish Interprofessional Lemon and Grapefruit Association and the Bioeconomy team of the Murcian Institute for Agricultural and Environmental Development (IMIDA).

The data used were obtained from in situ surveys conducted with AILIMPO’s technicians, as well as technicians that work at the Regional Agricultural Offices (OCAS) and leading regional companies of the citrus sector.

Based on this information, an operational model was established for each of the main organic lemon production systems in SE Spain: organic Fino and organic Verna. These models encompass representative practices of organic lemon cultivation in SE Spain. The study area is described in Section 2.2 “Characterization of the study area” of the preceding article: “Economic and Environmental Assessment of Conventional Lemon Cultivation: The Case of Southeastern Spain” [29], which analyzes conventional lemon cultivation in SE Spain.

2.2. Establishment of Production Models

Using primary information, the following models were established:

• Organic Fino

The characteristics and differences (productivity, useful lives, varieties, flowering…) of Fino and Verna lemons are described in detail by García Castellanos et al. [29].

A professional farm model was designed with an area of 10 hectares, and a planting scheme of 7 m × 5 m (approximately 286 trees∙ha⁻¹) (

Table 1. Agronomic data of the two cultivation models of organic lemon production.

	Fino Organic	Verna Organic
CHARACTERISTICS
Useful life (years)	25	30
Planting scheme (m × m)	7 × 5	7 × 5
Yield during productive years (kg∙ha−1)	40,000	29,000
Non-fresh marketable yield (industry) (%)	14	12
Non-productive years	1	1
Partially productive years	4	5
INPUTS IN PRODUCTIVE YEARS
Machinery hours (h∙ha−1)	11.00	10.00
Diesel (machinery) (L∙ha−1)	122.54	116.50
Fertilizers (N-P2O5-K2O-CaO-MgO)	(120-35-105-15-5)	(100-30-85-15-5)
Organic liquid fertilizer (2-4-6) (L∙ha−1)	50.00	0.00
Organic liquid fertilizer (7% MgO) (L∙ha−1)	64.29	64.29
Organic liquid fertilizer (8-0-0) (L∙ha−1)	687.00	573.00
Organic liquid fertilizer (6% CaO) (L∙ha−1)	250.00	250.00
Organic liquid fertilizer (0.8-10-0) (L∙ha−1)	106.00	114.00
Organic liquid fertilizer (2-0-4) (L∙ha−1)	200.00	200.00
Manure (sheep/goat) (1.48-0.56-2.35) (kg∙ha−1)	4000.00	3330.00
Phytosanitary treatments
Bacillus thuringiensis (kg∙ha−1)	1.50	1.50
Neoseiulus californicus (n° insects∙ha−1)	200,000	200,000
Anagyrus vladimiri (n° insects∙ha−1)	1000	0
Aphytis melinus (n° insects∙ha−1)	60,000	60,000
Confusion pheromone Prays citri (diffusers∙ha−1)	0	300
Confusion pheromone Aonidiella aurantii (diffusers∙ha−1)	400	400
Paraffin oil (83%) (L∙ha−1)	60.00	60.00
Irrigation
Water (m3∙ha−1)	5600	5000
Fertigation electricity (kWh∙ha−1)	714.70	640.13

). The rootstock was Citrus macrophylla. The useful life of organic Fino lemon trees was considered to be 25 years, beginning with a 5-year formation period. In the first year there is no production, while production gradually increases from the second to the fifth year based on specific coefficients (

Table 2. Coefficients applied on the production of Fino and Verna for the formation years.

Gross Production	Year 1	Year 2	Year 3	Year 4	Year 5	Year 6
Coefficients Fino (%)	0	8	25	50	80	Adult
Coefficients Verna (%)	0	8	20	40	60	80

). For the remaining 20 years they were considered to be adult trees with an average gross production of 40,000 kg∙ha⁻¹ (with around 14% of the fruits being non-fresh marketable fruits). The water supply was 5600 m³∙ha⁻¹; although the optimal requirement would be approximately 6000 m³∙ha⁻¹ for both conventional and organic Fino lemons. Restrictions due to water scarcity prevent most farms from achieving this optimum value.

• Organic Verna

The model was established with an area of 10 hectares and a planting scheme of 7 m × 5 m (286 trees∙ha⁻¹); the rootstock was Citrus aurantium L. and intermediate wood of sweet orange (Citrus sinensis L.) was used for the graft. The lifespan of the organic Verna lemon tree was considered to be 30 years; 6 years of formation, considering that the first year there is no production and that from the second to the sixth year the production increases in accordance with the coefficients shown in Table 2. The remaining 24 years were considered fully productive. An average gross productivity of 29,000 kg∙ha⁻¹ was considered (12% of the production is non-fresh marketable) (Table 1). The water supply was 5000 m³∙ha⁻¹; as for Fino, the optimal supply would be somewhat higher, but water availability prevents it.

2.3. Economic Evaluation: Life Cycle Cost Analysis

LCC methodology was used for the economic evaluation of the models. This methodology consists of accounting for all the life cycle costs of a product, process, or service [37].

The LCC methodology was applied to economically assess two lemon cultivation models: organic Fino and organic Verna. It was also used to highlight the differences between organic and conventional production models, using the conventional models established by García Castellanos et al. [29] as a reference. To complement the LCA, the same system limit was used: the cultivation phase. The results are expressed in euros (€) per functional unit (FU) used in the LCA (1 kg of lemons). Nonetheless, the cost structure is presented in euros (€) per unit of surface area (hectare), as this is the standard procedure in agricultural economic evaluations [23,29,44,46]. The prices used are derived from surveys conducted annually by the Bioeconomy team with agricultural supply companies.

The cost analysis was performed by accounting for all the useful life of organic Fino and Verna lemon crops: preparation and planting phase, tree formation phase and the adult stage. It is fundamental to note that the main cost structure presented is for a full-yield year. However, costs per kilogram taking into account the formative stage will also be presented. For the formative years, inputs, in the same way as production, were calculated as a coefficient over a full-yield production cycle (

Table 3. Coefficients applied on the variable costs of Fino and Verna for the tree development years.

Variable Costs	Year 1	Year 2	Year 3	Year 4	Year 5	Year 6
Coefficients Fino (%)	20	35	60	75	85	Adult
Coefficients Verna (%)	20	30	45	65	80	90

).

The costs were categorized into fixed and variable [23,41,44,46,48,49]. Each cost presented, whether fixed or variable, already includes the opportunity cost [50]. In this case, an interest rate of 1.5% was applied, as in the previous paper. The land was assumed to be owned, and it was not considered a cost since it does not depreciate. A steady-state LCC [29,41] was employed; that is, no discount rate was applied, as the objective of this work was to account for production costs rather than assess the profitability of investments.

2.3.1. Fixed Costs

Fixed costs correspond to the costs associated with the amortization of assets. The straight-line method was used to calculate amortization. The final cost of each item, expressed in €∙ha⁻¹∙year⁻¹, includes its opportunity cost.

In the organic Fino and Verna models, the investments required are very similar to each other and also to conventional models [29], due to their similarity (farm area, tree spacing, soil preparation, plant material, etc.). The investments include all the infrastructure required for irrigation: irrigation equipment, irrigation network, and irrigation reservoir. The reservoir is sized to store half of the water for the month at maximum water demand. The irrigation equipment is sized based on the flow rate required by the emitters per unit area and the size of the farm. The irrigation network is sized in the same way, with polyethylene pipes (d = 63 mm and d = 16 mm) and 4 L∙h⁻¹ self-compensating drippers. The investments also include a shed for the irrigation equipment and tools, auxiliary material (hoes, shears, etc.), land preparation and planting, and a weed control mat. The weed control mat is mostly used in organic production models. It is put in place only once during the crop’s lifespan and its purpose is to prevent competition for resources between the tree and the weeds during the formative years of the tree. Preparation and planting involve the following tasks: uprooting or lifting with a moldboard plow, collecting the remains of the previous crop, loosening the soil, refining-leveling and forming the plateaus, and planting grafted nursery plants.

2.3.2. Variable Costs

Variable costs are those that can vary in the short term, that is, from one production cycle to the next. Machinery is considered a variable cost, as farms often use their machinery for other crops or for sporadic work on other farms. Therefore, market prices were used for the contracting of services.

The resources required for each production cycle, once the plantation has reached maturity, are outlined below. For the formative years, resources were calculated by applying a coefficient to the costs associated with adult trees. These formative years were taken into account in the compensated unit cost. All final production factor costs for each model include their corresponding opportunity cost. Harvesting costs were not included, as they are borne by the buyer; this commercial practice is prevalent in the case of lemons and other citrus fruits throughout SE Spain.

Below is a descriptive summary of each item included in the variable costs:

• Production insurance

In SE Spain, the most common coverage for lemon crops is for hail damage. The insurance cost was determined using information from the report written by Agroseguro “Coste Medio del Seguro en la Comunidad Autónoma de Murcia”.

• Pruning

Manual annual pruning is the most frequent practice in Southeastern Spain. This section covers the cost of the labor used to perform this task. After pruning, the wood is shredded between the rows of the trees and left on the surface as a mulch.

• Machinery

This includes the use of machinery and implements for activities such as phytosanitary treatments, light surface tillage for inter-row aeration, shredding of prunings, and manure application (every three years). It was considered that farms outsource these tasks. The cost of machinery was recorded at the unit market cost: tractor + implement + labor.

• Fertilizers

The fertilizer unit requirements (N-P₂O₅-K₂O-CaO-MgO) used to establish the fertilization programs were 120-35-105-15-5 for organic Fino and 100-30-85-15-5 for organic Verna. These quantities were established based on information extracted from surveys, taking into account the optimal balance of the lemon tree outlined in the fertilization programs recommended by MAGRAMA [51], as well as information from regional publications [52,53]. Liquid organic fertilizers are applied through fertigation. Zinc and manganese chelates are applied via foliar application. In addition, sheep or goat manure is applied every 3 years, in a furrow at the end of the plateaus in which the trees grow.

• Phytosanitary treatments

The phytosanitary treatments vary annually and from farm to farm due to various agroclimatic factors; however, survey data were used to establish an average treatment program for each model. The most common practice is two annual treatments with paraffin oil and biotechnological control. Regarding biotechnological control, in Fino the following were considered: two releases of Neoloseiulus californicus, one release of Anagyrus vladimiri, three releases of Aphytis melinus, and diffusers for the sexual confusion of Aonidiella aurantii. In Verna the following were considered: two releases of Neoloseiulis californicus, three releases of Aphytis melinus, and diffusers for the sexual confusion of Aonidiella aurantii and Prays citri.

• Clearing

The crop rows (plateaus) are cleared three times a year, on average, using a manual brush cutter.

• Maintenance

The maintenance cost was obtained as a percentage (1.50%) of the cost of the fixed assets: shed, irrigation equipment, irrigation reservoir, and irrigation network.

• Permanent staff

Farm owners typically work on management-related tasks: purchasing inputs, scheduling and controlling irrigation, hiring external services such as pruning, etc. This is reflected as a cost in hours per hectare and year.

• Water

The irrigation programs for Fino and Verna were designed using data from three SIAM (Murcia Agricultural Information System, accessed on 24 April 2025: http://siam.imida.es, accessed on 24 April 2025) agrometeorological stations located in representative regional lemon-growing areas: CA12 (La Palma), AL52 (Librilla), and MO22 (Molina de Segura). Monthly irrigation allocations were obtained from average data from the three stations over a five-year period. Using these data and the information from the surveys, annual water allocations were established (5600 m³∙ha⁻¹ for Fino and 5000 m³∙ha⁻¹ for Verna).

• Electrical energy (irrigation)

Energy consumption by the pumps used for fertigation.

2.4. Environmental Assessment: Life Cycle Analysis (LCA)

The environmental evaluation of the organic production models was conducted using LCA. This environmental assessment methodology allows for the analysis of the entire life cycle of any production process or service and quantifies the potential environmental impacts derived from it. It also enables the identification of the elements that contribute most to the impacts. It is standardized by ISO 14040-14044 [35,36] and consists of four stages:

2.4.1. Objective and Scope

This LCA was performed to evaluate and compare the environmental impacts of two lemon cultivation models characteristic of SE Spain: organic Fino and organic Verna. These models were also compared with the conventional production models established by García Castellanos et al. [29]. The functional unit (FU) used was 1 kg of lemons, and the entire analysis was referenced to this unit. The study was limited to the cultivation phase, which was the scope and limit of the analysis (Figure 1). The results are also presented per surface area (1 hectare). Both the functional units and the system boundaries of the analysis are aligned with those used in other studies on citrus crops [21,46,47,54,55,56,57]. It is important to note that, in both the economic and environmental analyses, harvesting is not considered, as it is carried out by the buyer. Since the models analyzed only produce one product (lemons), they were treated as monofunctional systems, and no environmental load allocation procedures were applied.

The components taken into account in the models studied were as follows:

• Infrastructure: this corresponds to the investment and fixed assets of the LCC. It involves the fuel and lubricants consumed by machinery during land preparation and planting, and their emissions into the atmosphere; the production process of young plants in the nursery (taken from Ecoinvent); the irrigation equipment, irrigation network, and weed control mat, accounting for their raw materials, manufacture, and transportation; the reservoir, taking into account the fuel and lubricant consumed in its construction and their emissions, as well as the necessary raw materials, their manufacture, and their transportation.
• Machinery: the fuel and lubricant consumed by machinery during agricultural work in the production cycle and their emissions into the atmosphere.
• Fertilizers: the production of organic fertilizers and their transportation, packaging, and atmospheric emissions (derived from the application of nitrogen fertilizers in the field). Manure and the emissions following its application in the field were also considered.
• Pesticides: the production of pesticides, their packaging, and their transport, as well as their emissions into soil, air, and water, applying the fixed emission factors established by the EU [58]. The electrical energy consumed in the production of insects used in biological control was also taken into account. For pheromone diffusers, the plastic and its transport were also included.
• Electrical energy: the electrical energy consumed during fertigation.
• Waste treatment: the treatment of infrastructure and packaging (metals and plastics) that have reached the end of their useful life. It was considered that 80% of these materials are recycled and the remaining 20% end up in landfills. Prunings were not considered waste since they are shredded and used as a mulch.

The LCA was carried out accounting for the entire useful life of the crop, including the formative years during which production and inputs vary according to the coefficients shown in Table 2 and Table 3. The useful life of the materials was also taken into account: the reservoir has a useful life of 30 years; the irrigation equipment 15 years; and the irrigation network 10 years. The life of the weed control mat was considered to be the same as that of the trees, as it is only installed once during the entire useful life of the crop.

2.4.2. Life Cycle Inventory Analysis

The foreground data obtained from surveys are exposed in relation to the FU in

Table 4. Life cycle inventory of primary data of Fino and Verna lemon crops in relation to the functional unit: 1 kg of lemons.

	Fino Organic	Verna Organic
INFRASTRUCTURE
Preparation and Planting
Diesel (g∙kg−1)	0.2382	0.2725
Lubricant oil (g∙kg−1)	0.0003	0.0003
Manure (kg∙kg−1)	0.1338	0.1321
Local transportation (kg∙km∙kg−1)	0.0067	6.6043
Irrigation reservoir
Diesel (g∙kg−1)	0.3906	0.5361
Lubricant oil (g∙kg−1)	0.0004	0.0006
HDPE sheet (g∙kg−1)	0.1338	0.1837
Local transportation (kg∙km∙kg−1)	0.0067	0.0092
Irrigation equipment
Iron (mg∙kg−1)	9.6317	13.2219
Steel (mg∙kg−1)	0.9632	1.3222
Copper (mg∙kg−1)	2.8895	3.9666
Brass (mg∙kg−1)	0.1926	0.2644
PVC pipe (mg∙kg−1)	7.7053	10.5775
LDPE pipe (mg∙kg−1)	0.3853	0.5289
Polyamide (mg∙kg−1)	0.5779	0.7933
HDPE tanks (mg∙kg−1)	8.6685	11.8997
Local transportation (kg∙km∙kg−1)	0.0016	0.0021
Irrigation network
LDPE (g∙kg−1)	0.4986	0.6845
Local transportation (kg∙km∙kg−1)	0.0249	0.0342
Weed control mat
Polypropylene (g∙kg−1)	0.4883	0.5586
Local transportation (kg∙km∙kg−1)	0.0244	0.0279
SUPPLIES
Agricultural machinery
Diesel (g∙kg−1)	2.6809	3.4988
Lubricant oil (g∙kg−1)	0.0029	0.0038
Fertilizers
Organic liquid fertilizer (2-4-6) (g K2O∙kg−1)	0.0789	0.0000
Organic liquid fertilizer (7% MgO) (g∙kg−1)	1.8932	2.5989
Organic liquid fertilizer (8-0-0) (g N∙kg−1)	1.2053	1.6365
Organic liquid fertilizer (6% CaO) (g∙kg−1)	6.5736	9.0240
Organic liquid fertilizer (0.8-10-0) (g P2O5∙kg−1)	0.2998	0.4115
Organic liquid fertilizer (2-0-4) (g∙kg−1)	0.2104	0.2888
Local transportation (kg∙km∙kg−1)	1.6552	2.1820
Manure (1.48-0.56-2.35) (g N∙kg−1)	1.7106	1.9549
Local transportation (kg∙km∙kg−1)	5.7790	6.6043
Phytosanitary products
Insects production (kWh∙kg−1)	0.0038	0.0035
LDPE Diffusers (g∙kg−1)	0.0207	0.0388
Local transportation (kg∙km∙kg−1)	0.0010	0.0019
Paraffin oil (83%) (g·kg−1)	1.3095	1.7976
Local transportation (kg∙km∙kg−1)	0.0920	0.1263
Irrigation
Electricity (kWh∙kg−1)	0.2047	0.2537

. Due to the large amount of data involved, a software tool was required to develop the LCA. In this case, SimaPro 9.6 software (developed by Pré Sustainability) was used; this allows one to work with very extensive inventory and methodological databases. The background data (fuel, energy, materials, products, and transportation) were extracted from the Ecoinvent 3.10 database. This database has been used in LCAs of diverse agri-food products [5,30,59,60] and in the citrus sector [54], and is integrated in SimaPro.

Zinc, and manganese chelates and amino acids were not taken into account in the evaluation since they are not included in Ecoinvent and the quantities applied are very low. The same is true for Bacillus thuringiensis. Neoseiulus californicus, Anagyrus vladimiri, and Aphytis melinus also do not appear in the databases, but energy consumption data for their production were obtained from a company located in SE Spain.

Other limitations of the study are worth highlighting, such as the lack of specific organic fertilizers in the databases, which coincides with the limitations pointed out by other authors [21,61]. Therefore, production was modeled using generic organic fertilizer processes from the Ecoinvent market section, based on their major component (nitrogen, phosphorus, or potassium). Likewise, the technical data sheets for liquid organic fertilizers contain very limited information on the nature and proportion of their constituents. The impacts derived from the cultivation of young plants in a nursery were considered as the Ecoinvent process, corresponding to the cultivation of fruit trees in a nursery.

Air emissions derived from the combustion of diesel fuel by agricultural machinery were estimated using emission factors established by the EEA [62]. Air emissions resulting from the application of nitrogen fertilizers to agricultural soil were calculated based on the IPCC [63] and EEA [62] guidelines: NH₃ and NO₂ [62] and direct and indirect N₂O emissions [63]. Leaching of nitrate and phosphates was not taken into account since the IPCC [63] indicated that the leached fraction can be considered zero in crop areas with warm climates and where drip irrigation is used.

The inventory can be expressed per hectare by multiplying by the compensated gross yield (which accounts for the tree’s useful life): organic Fino (34,608 kg∙ha⁻¹) and organic Verna (25,211 kg∙ha⁻¹).

2.4.3. Life Cycle Impact: Assessment and Interpretation

To determine the magnitude and significance of potential environmental impacts, the CML-IA Baseline 4.7 midpoint assessment methodology (available in SimaPro) was used. This methodology is widely used for impact assessment in the agri-food sector [37,64,65,66,67,68,69], particularly in the citrus sector [54]. CML-IA Baseline 4.7 includes 11 impact categories: abiotic depletion (AD), abiotic depletion fossil fuels (ADFF), global warming (GW), ozone layer depletion (OLD), human toxicity (HT), freshwater aquatic ecotoxicity (FWAE), marine aquatic ecotoxicity (MAE), terrestrial ecotoxicity (TE), photochemical oxidation (PO), acidification (A), and eutrophication (E).

For the interpretation of the results, a contribution analysis was performed to observe the percentage in which each element/component contributes to each impact category. Furthermore, the overall contribution [29,30] was also calculated; this indicates the percentage of contribution of each element to the overall environmental impact generated by the production system.

2.5. Sensitivity Analysis

Finally, a sensitivity analysis was performed, introducing variability in two components, one in economic analysis and the other in the environmental analysis:

2.5.1. Economic

Non-fresh marketable fruit: As indicated by García Castellanos et al. [29], non-fresh marketable yield is rising in both conventional and organic production, and there is great variability in its percentage presence among campaigns and farms. Furthermore, it is noteworthy that in organic production buyers are becoming increasingly less lenient regarding the fruit’s appearance, resulting in high unmarketable rates that do not consider the inherent challenges of organic management, where effective pest control is complex. Non-fresh marketable fruits are destined for industrial processing and have a low price; when this is discounted, the cost of fresh lemon suffers significant increases. In this context, a sensitivity analysis was performed to evaluate how variability in non-fresh marketable fruits affects the cost of compensated fresh lemon, considering ranges of ±25% and ±50% around the average unmarketability established in conventional and organic scenarios.

2.5.2. Environmental

Fertilization: Organic fertilization is a key factor in this analysis, as, from an LCA perspective, it is one of the components that makes organic lemons less impactful overall than conventional lemons. Likewise, the scientific community highlights the synthesis of inorganic fertilizers as one of the main environmental critical points in various crops. Furthermore, organic fertilizers could come from waste or byproducts of the crop and livestock sector. Existing nutrients could be reused, and synthetic fertilizer manufacturing processes could be avoided [9]. In this sense, it is important to have a holistic view, which not only considers the life cycle of organic fertilizers but also the impact derived from the reduction in the use of synthetic fertilizers [44,70]. Therefore, the sensitivity analysis took into account the avoidance of generic inorganic N, P and K fertilizers, considering the fertilizer balances of organic Fino and Verna. The results of this analysis were evaluated using the relative difference (RD) between the different environmental impact categories. RD (%) = 100 × (S0 − S1)/S0, where S1 is the proposed scenario and S0 is the initial scenario.

3. Results and Discussion

3.1. Economic Analysis: Life Cycle Cost

The investment per hectare is high and similar in organic Fino and Verna, due to the similarity of the plant material, tree spacing, irrigation network, etc. Furthermore, it is higher than the investment in the conventional production model [29], since the organic models include an anti-weed geotextile mat on the crop plateaus, which amounts to 1729 €∙ha⁻¹ (

Table A1. Amortization of the investment for organic Fino lemon.

	Initial Investment for the Farm (€)	Initial Investment (€·ha−1)	Useful Life (Years)	Residual Value (€·ha−1)	Amortization (€·ha−1·Year−1)	Fixed Costs * (€·ha−1·Year−1)
Shed for equipment	16,000.0	1600.0	30.0	400.0	40.0	41
Preparation and planting	35,500.7	3550.1	25.0	0.0	142.0	144
Irrigation reservoir	31,744.2	3174.4	30.0	794.0	79.0	81
Irrigation equipment	13,125.0	1312.5	15.0	0.0	88.0	89
Irrigation network	18,972.9	1897.3	10.0	0.0	190.0	193
Weed control mat	17,290.0	1728.0	25.0	0.0	69.0	70
Various	1250.0	125.0	5.0	0.0	25.0	25
	133,882.8	13,388.3				643

The fixed cost of each concept expressed in €·ha⁻¹·year⁻¹ includes the opportunity cost *.

and

Table A2. Amortization of the investment for organic Verna lemon.

	Initial Investment for the Farm (€)	Initial Investment (€·ha−1)	Useful Life (Years)	Residual Value (€·ha−1)	Amortization (€·ha−1·Year−1)	Fixed Costs * (€·ha−1·Year−1)
Shed for equipment	16,000.0	1600.0	30.0	400.0	40.0	41
Preparation and planting	37,215.0	3721.5	30.0	0.0	124.0	126
Irrigation reservoir	28,344.0	2834.4	30.0	709.0	71.0	72
Irrigation equipment	13,125.0	1312.5	15.0	0.0	88.0	89
Irrigation network	18,972.9	1897.3	10.0	0.0	190.0	193
Weed control mat	17,290.0	1729.0	30.0	0.0	58	59
Various	1250.0	125.0	5.0	0.0	25.0	25
	132,196.9	13,219.7				604

The fixed cost of each concept expressed in €·ha⁻¹·year⁻¹ includes the opportunity cost *.

). This is put in place at the time of planting but is not usually renewed at the end of its useful life, since at that time the trees are fully developed and the corresponding shade hinders the development of weeds, which are eliminated from the plateaus by manual clearing. As already indicated by García Castellanos et al. [29], citrus trees in general, and lemon trees in particular, usually require a lower investment than stone fruit trees such as peach or plum, since the latter have higher plantation costs [71], due to the payment of royalties on varieties, higher planting density, and shorter useful lives (constant varietal commercial renewal).

In relation to the cost structure (

Table 5. Cost structure. Absolute annual costs in €∙ha⁻¹, and relative costs in relation to the total costs (%).

	Fino Organic		Verna Organic
	Absolute Annual Costs (€∙ha−1)	Relative Costs (%)	Absolute Annual Costs (€∙ha−1)	Relative Costs (%)
Fixed costs (FC)
Shed for equipment	41	0.36%	41	0.38%
Preparation and planting	144	1.25%	126	1.17%
Irrigation reservoir	81	0.70%	72	0.67%
Irrigation equipment	89	0.77%	89	0.83%
Irrigation network	193	1.68%	193	1.80%
Weed control mat	70	0.61%	58	0.54%
Various materials	25	0.22%	25	0.23%
Total fixed costs	643	5.59%	604	5.62%
Variable costs (VC)
Insurance	698	6.07%	518	4.82%
Pruning	1131	9.83%	1028	9.57%
Machinery	421	3.66%	400	3.72%
Fertilizers	2289	19.89%	2063	19.20%
Phytosanitary products	265	2.30%	265	2.47%
Biotechnological products	1250	10.86%	1297	12.07%
Clearing	238	2.07%	238	2.21%
Maintenance of infrastructure	122	1.06%	116	1.08%
Irrigation energy	185	1.61%	165	1.54%
Irrigation water	1989	17.29%	1776	16.53%
Permanent staff	2276	19.82%	2276	21.18%
Total variable costs	10,864	94.41%	10,142	94.38%
Total costs (TC)	11,507	100.00%	10,746	100.00%
Gross lemon cost * (€∙kg−1)	0.288		0.371
Fresh lemon cost ** (€∙kg−1)	0.335		0.421
Compensated gross lemon cost *** (€∙kg−1)	0.307		0.392
Compensated fresh lemon cost **** (€∙kg−1)	0.357		0.446

Gross lemon cost * (€∙kg⁻¹): cost per kilo of total lemons produced in the adult state. Fresh lemon cost ** (€∙kg⁻¹): cost per kilo of fresh lemons (discounting lemons intended to industry) produced in the adult state. Compensated gross lemon cost *** (€∙kg⁻¹): cost per kilo of total lemons taking into account the entire useful life. Compensated fresh lemon cost **** (€∙kg⁻¹): cost per kilo of fresh lemons (discounting lemons intended to industry) taking into account the entire useful life.

), the fixed costs are relatively low, representing only 6% of total annual costs. This is because lemon trees are woody crops with long useful lives, which reduces the impact of the investment due to a lower and gradual amortization over time. The low importance of fixed costs is in line with other works on citrus in the Mediterranean [46,71,72] and, of course, with the fixed assets in conventional lemon cultivation [29], since the investment and the useful lives of the assets are similar, as in the work of Pergola et al. [46]. The most important fixed cost corresponds to the irrigation infrastructure (network, equipment, and reservoir), which accounts for just over 56% of the fixed costs. The anti-weed mat, the most characteristic element of the organic approach, is not economically significant, representing only 0.61% (Fino) and 0.54% (Verna) of the total production cost (Table 5). The fixed costs are slightly lower for Verna due to its longer lifespan.

For both Fino and Verna, the most significant costs in organic farming are, by order of magnitude, the variable costs associated with labor (permanent staff, pruning, the use of agricultural machinery, and clearing), fertilizers, irrigation (water and electricity), and sanitary control (biotechnological control + phytosanitary treatments). This is quite similar to what occurs in conventional farming [29]. However, the cost of fertilization in organic farming is more than double that in conventional farming, due to the higher cost of the organic liquid fertilizers applied in fertigation. Torres et al. [24], in an analysis of citrus crops in SE Spain, also pointed out that fertilization is considerably higher in organic farming due to this same factor. One way to reduce fertilization costs is by applying solid fertilizers such as manure, pellets, or formulated composts [44]; it is very important to manage these resources so that they are efficiently assimilated. In the organic accounting structure, the cost of sanitary control is higher, also more than double that of conventional farming. Biotechnological control is gaining importance to the detriment of phytosanitary products.

As stated in several studies on citrus fruits in the European Mediterranean region [23,24,29,46,73], labor-related costs are the most significant. However, the case of lemons in SE Spain stands out greatly in this regard, as it is one of the few crops in which the harvest is the responsibility of the buyer and, therefore, is not included in the cost structure. In terms of employment, organic Fino and Verna generate 0.19 gross compensated AWU∙ha⁻¹∙year⁻¹ and, including harvesting, they generate 0.40 gross compensated AWU∙ha⁻¹∙year⁻¹ (742 h∙ha⁻¹) in Fino and 0.34 gross compensated AWU∙ha⁻¹∙year⁻¹ (616 h∙ha⁻¹) in Verna (1 AWU is equivalent to 1840 h). These values are close to those obtained by Pergola et al. [46] for organic lemon cultivation in Sicily. Lemon cultivation has a marked social character in relation to other crops, such as olive and almond trees, in SE Spain [74]. However, lemon crops generate approximately half the employment (in gross AWU; trees in full production) of stone fruit trees (0.72 gross AWU ha⁻¹∙year⁻¹). This difference is due to the manual thinning and green pruning tasks performed on stone fruit trees [71]. These values for organic lemon trees are identical or very similar to those of conventional lemon cultivation (0.34 in Verna and 0.43 in Fino), and this also occurs in other mediterranean areas [73]. In this case, the lower productivity of organic cultivation (kg∙ha⁻¹) and the associated labor costs, mainly harvesting, are partially offset by other manual tasks specific to organic cultivation, such as manual clearing (which replaces semi-mechanized herbicide treatments).

Fertilization is the second-most important cost in organic farming, due to the higher cost of the liquid organic fertilizers used in fertigation compared to inorganic ones [24]. For both Fino and Verna, fertilizers account for just over 19% of the total cost, closely followed by irrigation (over 18%). In absolute terms, the fertilization and irrigation costs are higher in Fino due to its greater vigor and productivity, which leads to higher input consumption [29]. However, in terms of production efficiency, as in conventional lemon cultivation, Fino has a lower fertilizer and irrigation cost per kilogram produced than Verna (Fino: 0.060 and 0.057 €∙kg⁻¹ gross compensated; Verna: 0.074 and 0.070 €∙kg⁻¹ gross compensated) [29]; it is more efficient in its use of these inputs. Furthermore, for both varieties, conventional cultivation is more efficient in relation to the cost of irrigation and fertilizers per kilogram, even though it requires more fertilizer units and a greater irrigation allocation. Its greater productivity reduces the unit cost of both factors. In the specific case of fertilization, the higher price of liquid organic fertilizers further increases the difference: the unit cost of organic fertilizers can be up to 3.5 times higher than that of conventional ones (for example, 0.060 €∙kg⁻¹ compared to 0.023 €∙kg⁻¹ for Fino) (

Table 6. Unit cost (€∙kg⁻¹) of irrigation and fertilization according to the production system.

	Fino		Verna
	Conventional (€∙kg−1)	Organic (€∙kg−1)	Conventional (€∙kg−1)	Organic (€∙kg−1)
Fertilizers	0.023	0.060	0.029	0.074
Irrigation (water + energy)	0.052	0.057	0.068	0.070

Source: García Castellanos et al. [29].

). Therefore, if the European Union intends to promote the widespread use of an organic fertilization accounting section, the prices of these inputs should be reduced. Promotion and expansion of the use of organic fertilizers is even more important in areas such as SE Spain, where soils are poor in organic matter, and vulnerable to climate change and desertification. Their application as a substitute for inorganic fertilizers would not only contribute to the conservation of soil but also improve its agronomic properties [44].

As indicated by García Castellanos et al. [29], in conventional lemon cultivation there is an ongoing increase in the use of biotechnological control, due to the reduction of available phytosanitary active ingredients and the additional benefits it offers, although it does not yet represent the majority of cases. By contrast, in organic production, the banning or limitation of the use of certain active ingredients has accelerated the establishment of biotechnological control, through the application of sexual confusion pheromones and controlled releases of auxiliary fauna, so that the outlay on phytosanitary products is considerably lower in organic farming; however, biotechnological control has a relatively high cost. The combined cost of permitted phytosanitary products and biotechnological control occupies fourth position in the relative importance to organic farming in relation to the total cost (13.16% in Fino and 14.54% in Verna). The higher relative cost for Verna arises from its greater sensitivity to Prays citri, due to its greater reflorescence and, therefore, its greater temporal extension [29].

Organic farming has a higher unit cost (€∙kg⁻¹) [24,29] than conventional farming (Fino: 0.357 vs. 0.278 and Verna 0.446 vs. 0.370, in €∙kg⁻¹ fresh compensated), due to lower productivity and, in the case of SE Spain, higher costs of fertilization (fertigation with liquid organic fertilizers) and sanitary control (phytosanitary products + biotechnological control). However, this higher cost can be offset by a higher unit price of organic lemons [73,75]. Likewise, the unit cost of the organic Verna lemon is higher than that of the Fino, as occurs in conventional cultivation, for the same reasons [29]: (1) its lower productivity and (2) an investment that is practically identical to that of Fino and a very similar consumption of inputs. The costs of compensated fresh lemon are considerably higher than those of gross lemon, since the high rate of non-fresh marketable fruits that currently arises in the sector (which is destined for industry and has a low market price) is discounted and the years of tree formation are accounted for, during which costs are incurred and production is lower. The percentage of non-fresh marketable fruits has always been lower in organic cultivation, but the demands of consumers and distribution chains are increasingly narrowing the gap between conventional and organic, especially with regard to visual appearance.

It should also be noted that, in the analysis of agronomic crop costs, direct comparison of the absolute results obtained with those of other studies is not feasible due to the following: (1) the variability in agronomic crop practices depending on the region: fertigation and use of liquid organic fertilizers or use of organic amendments (solid) or a combination of both in the case of organic farming, use of biotechnological control or phytosanitary products or a combination of both; (2) variability in prices depending on the year and location; and (3) the type of crop management (degree of technology) and soil and climatic conditions of the study area. All of this, among other factors, can significantly influence production costs and the productivity of the systems. For example, studies such as those by Pergola et al. [46] and Falcone et al. [73] have shown that, under certain conditions, organic citrus farming can be less costly per unit area than conventional farming, although it is still less productive. Therefore, although direct comparisons of absolute values in distant geographical areas are not possible, the relative importance of production factors can be analyzed and any similarities with other studies can be seen, as in this paper.

3.2. Environmental Analysis: Life Cycle Assessment

3.2.1. Contribution Analysis

In the organic system (

Table 7. Characterization of the potential environmental impacts and contributions of the components of the system for organic Fino and Verna. FU: 1 kg of lemons.

Impact Category	Absolute Values	Infrastructure	Machinery	Energy	Fertilizers Production	Fertilizers Emissions	Pesticides	Waste Treatment
Fino Organic	Contributions (%)
AD (kg Sb-eq)	2.49 ∙ 10−7	28.14	0.62	26.78	48.11	0.00	11.06	−14.72
ADFF (MJ)	5.00 ∙ 10−1	26.62	29.56	10.02	41.85	0.00	16.19	−24.24
GW (kg CO2-eq)	5.33 ∙ 10−2	14.56	21.05	7.03	45.54	14.42	3.46	−6.06
OLD (kg CFC−11-eq)	6.41 ∙ 10−10	36.98	28.08	8.84	56.32	0.00	3.97	−24.19
HT (kg 1,4-DB-eq)	1.08 ∙ 10−1	19.54	6.20	12.82	69.56	0.19	5.23	−13.54
FWAE (kg 1,4-DB-eq)	5.34 ∙ 10−2	8.99	1.47	5.34	85.13	0.00	2.48	−3.41
MAE (kg 1,4-DB-eq)	4.98 ∙ 101	18.85	5.49	13.16	67.13	0.00	5.60	−10.23
TE (kg 1,4-DB-eq)	1.54 ∙ 10−2	1.13	0.36	0.60	98.31	0.00	0.27	−0.67
PO (kg C2H4-eq)	1.48 ∙ 10−5	14.90	9.52	4.39	54.42	23.03	2.72	−8.98
A (kg SO2-eq)	1.24 ∙ 10−3	8.54	0.93	1.12	13.81	75.50	0.74	−0.63
E (kg PO4-eq)	3.89 ∙ 10−4	7.13	0.47	0.99	34.80	55.18	0.56	−0.88
Overall contribution (%)		15.94	9.43	8.28	55.91	15.30	4.75	−9.62
Verna organic
AD (kg Sb-eq)	3.16 ∙ 10−7	28.76	0.64	22.71	53.45	0.00	9.98	−15.53
ADFF (MJ)	6.94 ∙ 10−1	24.30	27.83	7.79	48.08	0.00	15.45	−23.44
GW (kg CO2-eq)	6.78 ∙ 10−2	14.40	21.61	5.96	47.18	14.00	3.24	−6.39
OLD (kg CFC−11-eq)	8.49 ∙ 10−10	25.60	27.67	7.19	60.42	0.00	3.60	−24.48
HT (kg 1,4-DB-eq)	1.35 ∙ 10−1	19.50	6.43	10.97	72.65	0.12	4.80	−14.47
FWAE (kg 1,4-DB-eq)	7.02 ∙ 10−2	8.54	1.46	4.38	86.88	0.00	2.22	−3.48
MAE (kg 1,4-DB-eq)	6.21 ∙ 101	18.96	5.75	11.36	69.73	0.00	5.23	−11.02
TE (kg 1,4-DB-eq)	2.10 ∙ 10−2	1.02	0.34	0.48	98.59	0.00	0.23	−0.66
PO (kg C2H4-eq)	1.71 ∙ 10−5	16.60	10.76	4.09	62.04	13.97	2.97	−10.43
A (kg SO2-eq)	1.47 ∙ 10−3	9.32	1.01	1.01	15.10	73.49	0.77	−0.70
E (kg PO4-eq)	4.68 ∙ 10−4	7.64	0.51	0.88	36.29	53.14	0.56	0.98
Overall contribution (%)		15.88	9.46	6.98	59.13	14.07	4.46	−9.97

Abiotic depletion (AD), abiotic depletion fossil fuels (ADFFs), global warming (GW), ozone layer depletion (OLD), human toxicity (HT), freshwater aquatic ecotoxicity (FWAE), marine aquatic ecotoxicity (MAE), terrestrial ecotoxicity (TE), photochemical oxidation (PO), acidification (A), and eutrophication (E).

), as in the conventional system, Verna exhibits higher absolute values than Fino in all impact categories due to its lower productivity [29]. The contributions of the different components of the system to the impact categories are very similar in both organic crops, given their very similar infrastructure and inputs, a pattern that is also observed in the conventional crops [29].

Fertilizers are the main component contributing to the overall impacts of the Fino and Verna organic farming models (Table 7 and Figure 2). Their production represents 56% and 59%, respectively, while emissions derived from the application of nitrogen fertilizers in the field represent 15% and 14%, respectively. Fertilizer production, therefore, stands out in all impact categories, with contributions greater than 40%, except in A and E. Its contribution is especially high in the toxicity categories (HT, FWAE, MAE, and TE), being 70% or greater, due to the manufacture of organic nitrogen and phosphorus fertilizers. Emissions derived from the application of fertilizers have a great impact in A and E, due to the release of NH₃, which coincides with what was pointed out by Ribal et al. [56]. Likewise, they are relevant in PO (23% in Fino and 14% in Verna), where their impact is associated with the release of NO₂, and to a lesser extent with GW (14% in Fino and Verna) [56], due to the emission of N₂O.

Infrastructure is the second-most important component in the overall impact of the organic models, contributing 16% in both Fino and Verna. Infrastructure is more important than in conventional models regarding the overall impact of these models, since, despite their lower productivity, organic Fino and Verna require a similar but higher investment (including anti-weed mat) than conventional models. The contribution of infrastructure is notable in the AD, ADFF, OLD, HT, and MAE categories (19% to 29% in both Fino and Verna), due to the irrigation network and the weed control mat. Furthermore, in AD, HT, and MAE, the metals of the irrigation equipment also play a significant role.

Other components such as machinery, fertigation energy, and pesticides make small contributions to the overall impact (less than 10% in both Fino and Verna). These contributions are similar to those in conventional farming [29]. Machinery is significant in the ADFF, OLD, and GW categories; in the first two, the impact comes from the diesel production process, while for GW it is due to emissions derived from diesel combustion in agricultural machinery.

Waste management takes on greater importance (−10%) in the overall impact of ecological models compared to conventional ones [29]. This component only considers the final destination of waste, and 80% of the plastics and metals in the process are recycled, making it negative. Its importance increases because liquid fertilizer containers weigh approximately nine times more than those of solid synthetic fertilizers (0.9 kg vs. 0.1 kg). This implies higher consumption of plastic (included in the fertilizer component), but also an increase in its recycling. In 10 of the 11 impact categories, waste management makes a negative contribution, particularly in ADFF and OLD, where it generates the greatest environmental benefits.

The profile of the components’ contributions to the overall impact differs from other studies on organic citrus [46,56]. This may be due to the fact that some studies considered manure as the sole source of fertilization and to the fact that some authors did not consider the environmental burdens of manure (livestock byproduct).

3.2.2. Conventional vs. Organic

When comparing organic management with conventional management [29], the former has lower absolute values in seven (AD, ADFF, GW, OLD, HT, MAE, and PO) of the eleven impact categories, both per unit of mass and per unit of area (

Table 8. Conventional vs. organic lemon cultivation, expressed by mass or area units.

Impact Category	Fino Organic	Fino Conventional	Verna Organic	Verna Conventional	RD Fino Organic vs. Conventional	RD Verna Organic vs. Conventional
FU:1 kg
AD (kg Sb-eq)	2.49 ∙ 10−7	5.54 · 10−7	3.16 · 10−7	6.91 · 10−7	−122.52	−118.54
ADFF (MJ)	5.00 ∙ 10−1	7.64 · 10−1	6.94 · 10−1	9.68 · 10−1	−52.73	−39.59
GW (kg CO2-eq)	5.33 ∙ 10−2	6.47 · 10−2	6.78 · 10−2	8.25 · 10−2	−21.41	−21.67
OLD (kg CFC−11-eq)	6.41 ∙ 10−10	1.95 · 10−9	8.49 · 10−10	2.44 · 10−9	−204.75	−187.42
HT (kg 1.4-DB-eq)	1.08 ∙ 10−1	1.37 · 10−1	1.35 · 10−1	1.71 · 10−1	−27.32	−26.33
FWAE (kg 1.4-DB-eq)	5.34 ∙ 10−2	3.06 · 10−2	7.02 · 10−2	3.79 · 10−2	42.68	45.95
MAE (kg 1.4-DB-eq)	4.98 ∙ 101	1.05 · 102	6.21 · 101	1.31 · 102	−110.23	−111.68
TE (kg 1.4-DB-eq)	1.54 ∙ 10−2	1.00 · 10−3	2.10 · 10−2	1.24 · 10−3	93.47	94.08
PO (kg C2H4-eq)	1.48 ∙ 10−5	2.16 · 10−5	1.71 · 10−5	2.72 · 10−5	−45.55	−58.98
A (kg SO2-eq)	1.24 ∙ 10−3	9.96 · 10−4	1.47 · 10−3	1.24 · 10−3	19.48	15.77
E (kg PO4-eq)	3.89 ∙ 10−4	2.16 · 10−4	4.68 · 10−4	2.68 · 10−4	44.38	42.70
FU: 1 ha
AD (kg Sb-eq)	8.62 · 10−3	2.20 · 10−2	7.97 · 10−3	1.86 · 10−2	−155.90	−133.61
ADFF (MJ)	1.73 · 104	3.04 · 104	1.75 · 104	2.61 · 104	−75.64	−49.21
GW (kg CO2-eq)	1.85 · 103	2.58 · 103	1.71 · 103	2.22 · 103	−39.62	−30.05
OLD (kg CFC−11-eq)	2.22 · 10−5	7.77 · 10−5	2.14 · 10−5	6.58 · 10−5	−250.46	−207.24
HT (kg 1.4-DB-eq)	3.72 · 103	5.45 · 103	3.41 · 103	4.61 · 103	−46.42	−35.04
FWAE (kg 1.4-DB-eq)	1.85 · 103	1.22 · 103	1.77 · 103	1.02 · 103	34.09	42.23
MAE (kg 1.4-DB-eq)	1.72 · 106	4.17 · 106	1.57 · 106	3.54 · 106	−141.76	−126.27
TE (kg 1.4-DB-eq)	5.32 · 102	3.99 · 101	5.29 · 102	3.35 · 101	92.50	93.67
PO (kg C2H4-eq)	5.13 · 10−1	8.59 · 10−1	4.32 · 10−1	7.34 · 10−1	−67.39	−69.93
A (kg SO2-eq)	4.28 · 101	3.96 · 101	3.72 · 101	3.35 · 101	7.41	9.96
E (kg PO4-eq)	1.35 · 101	8.61 · 100	1.18 · 101	7.22 · 100	36.04	38.75

Abiotic depletion (AD), abiotic depletion fossil fuels (ADFFs), global warming (GW), ozone layer depletion (OLD), human toxicity (HT), freshwater aquatic ecotoxicity (FWAE), marine aquatic ecotoxicity (MAE), terrestrial ecotoxicity (TE), photochemical oxidation (PO), acidification (A), and eutrophication (E).

). Other authors [21,25,56] also obtained lower values for most categories in organic citrus farms, both per kilogram and per hectare. In this study, the lower values for organic production are essentially due to a lower consumption of fertilizer units in organic production (high prices of liquid organic fertilizers) and the use of organic fertilizers instead of chemically synthesized fertilizers. Also influential, albeit in a secondary way, are the replacement of synthetic phytosanitary products by the use of biotechnological control, which in turn reduces the use of machinery, the replacement of herbicides by manual clearing with brush cutters, and the lower energy consumption in irrigation resulting from a lower supply. Abdallah et al. [21] analyzed grapefruit cultivation in SE Spain and indicated that the lower environmental footprint of organic cultivation is mainly due to the aforementioned factors.

The values of categories A and E are higher with organic management due to the emissions generated by the application of nitrogen fertilizers in the field (specifically NH₃), which coincides with the observations of other authors [30,56,76,77]. The superiority of organic management in these categories is due to the fact that the field emission factors of manure and other organic fertilizers are higher than those of inorganic fertilizers, according to the EEA [62].

It is important to highlight that when the results are expressed per unit of mass (of lemons) instead of surface area, the differences between the organic and conventional systems are reduced in the categories where the organic is less impactful but are accentuated in those where its impact is greater, due to its lower productivity. These differences are more pronounced for Fino, as the productivity gap between its organic and conventional management is greater compared to Verna.

3.2.3. Global Warming

The GW category is treated independently because, as indicated by García Castellanos et al. [29], it is the most used category in LCAs of agri-food products [47,54,68,78] and is recognized by a large proportion of the population due to its relevance as an environmental problem.

In this work, 0.0533 and 0.0678 kg CO₂ eq·kg⁻¹ were obtained for organic Fino and Verna, respectively. For Verna, the result is within the range of values (0.055–0.114 kg CO₂ eq·kg⁻¹) observed by different authors in LCAs of organic citrus fruits [25,46,56,79,80]. In contrast, Fino is slightly lower.

These low values are largely explained by differences in productivity [77], with the organic Fino (40 tn·ha⁻¹) and Verna (29 tn·ha⁻¹) systems showing high productivities compared to the range observed in the aforementioned works (18–30 tn·ha⁻¹). For example, Knudsen et al. [25] obtained higher values (large-scale farms: 0.114 kg eq of CO₂·kg⁻¹; small-scale farms: 0.084 kg CO₂ eq·kg⁻¹), essentially due to their lower yields, and in the case of oranges on large-scale farms, also to the greater use of fertilizer units. In comparison with Aguilera et al. [79], other factors are influential, in addition to higher productivity. One is the greater use of nitrogen fertilizer units (184 kg N·ha⁻¹); in this study, 120 kg N·ha⁻¹ were applied in Fino and 100 kg N·ha⁻¹ in Verna. As García Castellanos et al. [29] indicated, fertilization doses in recent years have been closely adjusted to crop requirements due to both economic factors and European policies seeking to reduce nitrate pollution. Likewise, Aguilera et al. [79] present a high irrigation allocation (7440 m³∙ha⁻¹; compared to 5600 m³∙ha⁻¹ in Fino and 5000 m³∙ha⁻¹ in Verna), which leads to higher energy consumption. In SE Spain, allocations above 6000 m³∙ha⁻¹ in citrus fruits are already very rare, due to the scarcity and high cost of water [29,81,82]. Likewise, Aguilera et al. [79] considered various phytosanitary products permitted in organic farming, while in this study only paraffinic oil and biological control were taken into account for pest management. For their part, Climent et al. [80] obtained results very similar to those of Verna for organic oranges in SE Spain, due to the similarity of both the productive factors and the productivity of the system. Ribal et al. [56] and Ribal et al. [77], also based in SE Spain, reported slightly higher values; this was essentially due to lower productivities. In any case, as García Castellanos et al. [29] indicated, in addition to the aforementioned factors, differences in results may be due to the fact that LCA studies on the same product do not always account for the same factors or apply the same characterization methods.

3.3. Sensitivity Analysis

3.3.1. Economic

Regarding the variability in the compensated production cost of fresh lemons due to variations in non-fresh marketable rates,

Table 9. Economic sensitivity analysis: variation of costs depending on the variation of non-fresh marketable yields.

	Fino Conventional		Verna Conventional		Fino Organic		Verna Organic
Variation of Discards	€∙kg−1	Variation of Costs	€∙kg−1	Variation of Costs	€∙kg−1	Variation of Costs	€∙kg−1	Variation of Costs
−50%	0.249	−11%	0.338	−9%	0.332	−7%	0.419	−9%
−25%	0.263	−6%	0.353	−5%	0.344	−4%	0.432	−5%
0%	0.280	0%	0.370	0%	0.357	0%	0.445	0%
25%	0.295	5%	0.389	5%	0.372	4%	0.461	6%
50%	0.315	12%	0.410	11%	0.387	8%	0.477	11%

All variations are assessed with respect to the baseline scenario (0% variation in non-fresh marketable fruits). The reported cost corresponds to the compensated cost of fresh lemon.

shows that conventional Fino lemons are more sensitive than organically grown ones; in other words, their relative variation (elasticity) is greater. This is logical, since conventional Fino lemon systems are more productive and have shown the highest non-fresh marketable rates in recent years. In the case of the Verna lemon tree, the system (conventional or organic) does not determine changes in the elasticity of the cost variable based on variations in non-fresh marketable rates. This is because Verna is a variety with lower non-fresh marketable rates, in general, and with lower vigor, which leads to smaller production differences between conventional and organic cultivation systems.

The increases in production costs range from 0.040 € per kilogram for conventional Verna to 0.030 € for organic Fino. These numbers may seem low, but, in reality, they can determine the economic viability of a farm. Thus, for example, in the most extreme case (conventional Fino), the increase of 0.035 € for a 30% non-fresh marketable rate represents a cost increase of 12% (Table 9). Graphically (Figure 3), the differences in the slopes of the lines indicate that there is little difference in the effect of non-fresh marketable rates on production costs across the different production systems.

3.3.2. Environmental

Since organic fertilizers could be composed of waste and byproducts from the agricultural sector, they could reuse existing nutrients and thus could avoid the production of synthetic fertilizers; the values of all impact categories are reduced in both Fino (between 5% and 141%) and Verna (between 4% and 125%). The most significant decreases are observed in AD, ADFF, GW, OLD, HT, FWAE, MAE, and PO (

Table 10. Environmental sensitivity analysis: RD between the baseline scenarios and the avoidance of inorganic NPK fertilization.

Impact Category	Fino Organic	Fino S1	Verna Organic	Verna S1	RD Fino Organic vs. S1	RD Verna Organic vs. S1
AD (kg Sb-eq)	2.49 ∙ 10−7	−1.01 · 10−7	3.16 · 10−7	−7.97 · 10−8	140.73	125.22
ADFF (MJ)	5.00 ∙ 10−1	1.00 · 10−1	6.94 · 10−1	2.41 · 10−1	79.96	65.27
GW (kg CO2-eq)	5.33 ∙ 10−2	2.53 · 10−2	6.78 · 10−2	3.61 · 10−2	52.54	46.73
OLD (kg CFC-11-eq)	6.41 ∙ 10−10	3.71 · 10−11	8.49 · 10−10	1.66 · 10−10	94.20	80.47
HT (kg 1.4-DB-eq)	1.08 ∙ 10−1	1.06 · 10−2	1.35 · 10−1	2.58 · 10−2	90.15	80.92
FWAE (kg 1.4-DB-eq)	5.34 ∙ 10−2	3.22 · 10−2	7.02 · 10−2	4.63 · 10−2	39.62	34.05
MAE (kg 1.4-DB-eq)	4.98 ∙ 101	4.88 · 100	6.21 · 101	1.13 · 101	90.20	81.75
TE (kg 1.4-DB-eq)	1.54 ∙ 10−2	1.46 · 10−2	2.10 · 10−2	2.01 · 10−2	4.72	3.91
PO (kg C2H4-eq)	1.48 ∙ 10−5	1.02 · 10−5	1.71 · 10−5	1.19 · 10−5	31.21	30.59
A (kg SO2-eq)	1.24 ∙ 10−3	1.11 · 10−3	1.47 · 10−3	1.33 · 10−3	10.14	9.62
E (kg PO4-eq)	3.89 ∙ 10−4	3.51 · 10−4	4.68 · 10−4	4.24 · 10−4	9.89	9.30

).

This approach is crucial, as the agricultural industry is essential for human nutrition and generates waste or byproducts with nutrients that can be reincorporated, promoting circular production systems that avoid the need for additional production processes, such as the chemical synthesis of fertilizers, which has a high environmental impact.

4. Conclusions

The cost structure of organic lemons is very similar to that of conventional lemons, the costs of organic lemons being higher due primarily to the higher cost of fertilization and phytosanitary control. The differences between organic Fino and Verna lemons are due to the same factors as for conventional lemons.

The high prices of liquid organic fertilizers limit the number of fertilizer units applied, which in turn limits crop productivity (among other factors). Organic farming is less resource-efficient than conventional farming, due to the high cost of certain inputs and lower productivity. Organic fertilization offers numerous agronomic advantages, being especially beneficial in soils with limiting soil and climatic conditions, such as those in SE Spain. Expanding the use of organic fertilizers would improve soil quality and resilience against desertification, in addition to aligning with the reduction in synthetic fertilizer use promoted by European policies, but this requires a reduction in the cost of these fertilizers. Organic fertilization can also be made cheaper by applying amendments such as manure and compost. However, these are not all directly assimilated; neither is there a supply tailored to the fertilizer balance required by each crop, so they are a partial solution.

Furthermore, the current high levels of non-fresh marketable fruits could compromise the economic viability of lemon production. Organic lemons are also showing an upward trend in this respect, and their pest management is more complex, so greater flexibility is needed on the part of distribution chains and consumers.

In environmental terms, the most impactful component continues to be fertilizer production. However, if it is considered that organic fertilizers reuse nutrients from agricultural byproducts and waste, thereby removing the need for the production of inorganic fertilizers, their impact is considerably lower. In any case, organic lemon production has less impact overall than conventional lemon production. The transition to organic fertilization can be an alternative depending on how it affects costs and productivity, as it must be profitable for the farmer. Likewise, the efficiency of fertilization must be maximized as food security is compromised, and it is necessary to produce more food with the least possible use of inputs.

Lemon production, both conventional and organic, in SE Spain has low GW values compared to other areas. In organic farming, this is due, among other factors, to high productivity, efficient fertilization tailored to the needs of the crop, climatic conditions that reduce the amounts of pesticides applied and the nitrous oxide emissions from nitrogen fertilizers, and the extensive use of biotechnological pest control.

In short, lemons grown under the conditions of SE Spain, in an organic system with fertigation, and destined for the fresh market, represent a sustainable product in both economic and environmental terms.

To conclude, some proposals are outlined for future research directions: (1) Conducting LCA studies on insects used in biological control is essential, as the literature in this field is scarce. (2) Exploring combined organic and inorganic fertilization strategies that enhance productivity while minimizing environmental impacts would be highly valuable. These approaches should be assessed from both economic and environmental perspectives to identify the optimal balance point and support more efficient production systems. (3) Further studies on composting agricultural and livestock residues and byproducts are needed to achieve nutrient balances adapted to the specific fertilization needs of each crop.