Stakeholders’ Preferences for Sustainable Agricultural Practices in Mediterranean Cereal Cropping Systems

Abstract

This study assesses local stakeholders’ perceptions regarding how a Mediterranean cereal-based cropping system could transition to a more sustainable production, focusing on the identification of the most suitable alternatives for their diversification. Fifty-four stakeholders from the Aragon region in Spain, including farmers, technical advisors, public agricultural officers, local researchers, and experts from environmental NGOs, were consulted. Their responses were analysed using multi-criteria decision-making techniques to order their preferences for different farming practices and diversification strategies. Stakeholders’ responses suggest a priority for balancing soil conservation with the economic viability and continuity of farms. This is evident not only in its consideration as a priority objective but also in their preferences for farming practices, where their implications for farm profitability, especially through the choice of less costly alternatives, are a main concern. This economic rationale also influences their choice of crop diversification alternatives, with a preference for short (two-year) rotations in rainfed cereals and double cropping in irrigated cereals, showing a consideration of the balance between environmental and economic sustainability, and for diversification crops that farmers are already familiar with, aiming both to reduce the uncertainties linked to new crops and to minimise the need for technical support.

1. Introduction

Because of their adaptability to different pedoclimatic conditions, cereals are the most widely grown crops worldwide, with nearly 739 million hectares cultivated and a production of over 3.13 billion tonnes in 2023 [1]. Their importance goes beyond their contribution to the economy of rural areas and to world trade, being a key component of human nutrition and food security, especially in developing countries.

As elsewhere, cereals are the main crops in Southern European agroecosystems, followed by trees (e.g., olive, almonds, vineyards) and horticultural crops. These include winter cereals like barley and wheat, historically grown in Mediterranean rainfed areas, and summer cereals, such as maize and sorgo, which require irrigation. For example, in Spain, 60% of the 9 million hectares of cropland are rainfed cereals, while 11% are irrigated cereals [2]. Despite the substantially larger area of rainfed cereals, irrigation is crucial to ensure stable food production in Mediterranean areas [3].

Historically, Spanish cereal production systems, both rainfed and irrigated, have heavily relied on external inputs. Intensive tillage (e.g., mouldboard ploughing) has for decades been the norm in large rainfed areas [4], contributing to a significant soil degradation, especially under the predominant cereal–fallow rotations or cereal monocultures. The typical cereal–fallow rotation, with 15 to 17 months of bare soil, an intensive tillage pass in winter and repeated vertical tillage passes to control weeds during the fallow, has been particularly harmful [5].

Scientific evidence has shown that major environmental problems linked to intensive tillage and the cereal–fallow alternance in rainfed systems include soil erosion [6], weak soil structure [7], and loss of soil organic carbon [8,9]. In rainfed areas where the cereal–fallow system is not used, monoculture prevails, leading to reduced soil organic matter content and carbon storage [10], microbial abundance [11], and aggregate stability [12] compared to more diversified cropping systems. In irrigated systems, monoculture, especially continuous maize, is also predominant, often under intensive production systems with a substantial input use, including irrigation water [13]. While this intensification has significantly increased crop yields [14], it has also brought negative environmental trade-offs, notably nitrate pollution [15], GHG emissions [16], and progressive soil salinization [17,18]. Moreover, monoculture, either rainfed or irrigated, are related to a higher incidence of plant pests, diseases, and weed infestation problems and to a declining biodiversity both above and below ground [19]. Studies suggest that diversification through intercropping or rotation with legumes enhances ecosystem resilience by supporting beneficial organisms and reducing the reliance on chemical controls [11,20].

To mitigate these environmental impacts and secure food provision, promoting sustainable agriculture that enhances agroecosystem biodiversity and multifunctionality is critical [21]. Practices such as crop diversification, conservation agriculture, water-saving irrigation, and optimized fertilization strategies offer both economic and environmental benefits [22]. However, their success depends on local soil and climate conditions and the need for integrated assessments of cropping systems [23]. Farming strategies must be tailored to the specific characteristics of Mediterranean agroecosystems [24,25].

Despite scientific consensus on the benefits of low-input practices, adoption remains limited [26]. Beyond profitability, adoption depends on economic, social, cultural, and institutional factors across the value chain [27,28], though increasingly supported by pubic policies. A major barrier is the limited experience and the subsequent uncertainty that farmers and technicians face about these practice’s potential to improve agronomic and environmental performance while reducing production costs [29,30,31]. Crop diversification, in particular, can improve economic sustainability in cereal production by stabilizing income, reducing input costs, and mitigating environmental risks [19,32]. However, introducing new complementary crops poses challenges, not only at the farm level, but also because of economic barriers such as additional costs and difficulties for the processing, sale and marketing of the new crops [33,34]. Policy initiatives like the European Green Deal [35] and the Farm to Fork Strategy [36] intend to overcome these obstacles by offering clear objectives and financial support for sustainable farming.

Bridging the gap between scientific evidence and farm-level implementation of more sustainable farming requires involving local stakeholders. Their practical expertise is key for identifying the most appropriate agricultural practices for each farming system, but also the barriers to adoption [37]. Farmers, in particular, are more effective in applying local knowledge to solve local problems [38]. Many traditional practices were displaced by intensive methods as farmers lacked guidance on how to combine them. Agricultural modernization led to simplified cropping systems and widespread monoculture [39,40]. Today, scientific evidence has demonstrated that sustainable practices are compatible with farm profitability [41]. Modern production technologies enable the integration of sustainable farming practices into conventional production systems. Similarly, most crops that are suitable for diversifying cropping systems are locally adapted or were traditionally cultivated but were displaced by more profitable ones. Local actors can thus contribute significantly with their expertise to a more successful diversified agriculture. Recent initiatives in the Mediterranean Region have demonstrated the value of participatory approaches and local knowledge in adapting, co-developing, and testing practices for more sustainable cereal production in countries such as Spain, Algeria [42], and Morocco [43]. Similar examples are the collaborative networks within the Operational Groups under the European Innovation Partnership for Agricultural Productivity and Sustainability (EIP-AGRI) [44].

This study aims to identify the most effective low-input practices for sustainable cereal production in a representative Spanish Mediterranean area based on key stakeholders’ perceptions. It also investigates locally suitable crop diversification alternatives. This study first identifies the main challenges hindering cereal production in the area, to latter identify those practices, particularly diversification strategies, that are perceived as more effective by stakeholders in addressing those challenges and advancing towards more sustainable cropping systems. After this introduction, the two cropping systems considered are described; followed by the methodology, results, and discussion; and ending with the main conclusions of the research.

2. Materials and Methods

2.1. Cereal Production in the Area of Study

We chose the Autonomous Community of Aragón in NE Spain, covering 47,720 km², as the study area (Figure 1). This region was selected for three main reasons as follows: (i) it has a very high proportion of land devoted to agriculture (around half its surface), (ii) nearly 25% of cropland is irrigated, and (iii) it is highly representative of the Mediterranean climate and cereal cropping systems. The climate is predominantly Mediterranean continental, with average annual temperatures and precipitation for the three main cities of 15.5 °C and 322 mm for Zaragoza, 12.2 °C and 378 mm for Teruel, and 14.0 °C and 480 mm for Huesca, respectively [45].

In Aragon, rainfed cropping systems are dominated by barley and wheat, which together account for more than 60% of the rainfed arable area. In irrigated conditions, barley, alfalfa, maize, and wheat account for over 90% of the irrigated arable area [2]. Agricultural management practices vary across the territory and between rainfed and irrigated lands. Rainfed cropping systems are dominated by cereal monocultures or the traditional cereal–fallow rotation, where long bare soil fallow periods (15–18 months) separate cereal-growing seasons. During fallow periods, intensive tillage, including one pass of mouldboard ploughing in winter, and vertical cultivators passes in spring to control weeds. In irrigated areas, maize monocultures and rotations involving alfalfa, maize, and wheat, are the two main cropping systems. The expansion of intensive livestock farming (especially swine) over the past two decades has increased the use of organic fertilizers in the region [15]. Although no-tillage (NT) is gaining ground in Aragon as an alternative to intensive tillage, most soils are still managed with tillage implements that involve soil disturbance.

2.2. Survey Questionnaire

Stakeholders’ perceptions of the most suitable farming practices for enhancing sustainability in Spanish Mediterranean cereal systems were collected through a questionnaire to the study area’s conditions, based on a literature review of sustainable agricultural practices in cereal production in Mediterranean Europe [46].

The first part of the survey questionnaire aimed to identify and assess problems, objectives for action, and farming practices, and asked for the following:

• Stakeholder’s characteristics;
• Qualitative assessments of the relevance of problems in each cropping system and of the priority given to possible actions to address these problems (objectives), with the option to propose additional problems or actions that they deemed appropriate;
• Identification of agricultural practices considered as suitable for the characteristics of each cereal cropping system, and of the reasons for perceiving some of these as non-suitable, again with the option to propose other practices;
• Qualitative assessment of how effective these practices are in contributing to advancing towards the consecution of each priority for action (objective).

The second part of the questionnaire focused on the options for crop diversification in cereal production. Stakeholders chose the most appropriate type of diversification for cereal production in the region among a list of the following three alternatives:

• Simultaneous/intercalated crops (intercropping) in the same plot;
• Crops in rotation in different years;
• Multiple crops (succession of crops within the same year).

A detailed explanation of what each type of diversification consists of was included.

After selecting their preferred diversification method, stakeholders selected the crop combinations that they considered as more appropriate for the type of diversification that they had chosen. Each respondent chose two possible diversification crops out of an open list selected from a literature review [46] or suggested other alternatives.

The survey targeted five stakeholder groups as follows: (1) farmers, (2) private technical agricultural advisors, (3) agricultural researchers, (4) public agricultural officers, and (5) experts from environmental NGOs. The interviewed stakeholders had previously participated in the DIVERFARMING project’s participatory activities. They were selected and contacted based on their expertise on cereal production in the study area, but they do not constitute a statistically significant sample. Researchers were selected from research groups of universities and research centers. Public agricultural officers belonged to the regional agricultural administration and included both policy and extension profiles. NGO experts were selected from regional NGO with areas of activity related to agriculture and had a technical profile. Farmers and technical advisors, from both cooperative and private companies, were selected with help from farmers’ unions and agricultural associations, that proposed potential participants. The selection process followed the expert criteria established by [47], which included verified subject matter expertise, willingness to engage actively, and strong communication skills. Participants met the minimum threshold required for decisional group formation following the methodology outlined by [48].

2.3. Statistical and Multicriteria Analysis

Questions involving a qualitative assessment (points 2 and 4 in Section 2.2) used a six-level scale to avoid neutral answers and ensure that respondents either expressed their opinion fully or chose the “do not answer” response [49]. Responses were converted to a 0 (very low) to 5 (very high) numerical scale. Data were statistically analyzed using STATA/SE 15. With some exceptions, a univariate descriptive analysis was conducted. Differences in responses by respondents’ type were analysed using the non-parametric Fisher’s exact probability test, which exactly measures the association between categorical variables.

Farming practices were ranked according to their effectiveness using multiple criteria alternative selection analysis [50]. In the multicriteria model, the alternatives to be selected were the set of farming practices proposed in the survey, while the selection criteria were the different priorities for action to advance towards a more sustainable cropping system. Stakeholders qualitatively assessed the effectiveness of each farming practice in contributing to the consecution of each priority for action (objectives) using a six-level ordinal scale. These responses were then transformed to numerical correlated values on a 0–5 scale and weighted using the assessment of the importance given by respondents to the priorities for actions (objectives). More detail is available in [51].

The multiple criteria selection methodology used was TOPSIS [52,53,54]. The outcome of the TOPSIS model, which uses the [55] extension for group decision-making, is an effectiveness index that ranks agricultural practices by their perceived effectiveness. The priority ranking of practices in the TOPSIS multicriteria analysis was calculated independently for each stakeholder type. In this process, an equal weight was assigned to each expert, with the weights normalized to the unity. Then, these individual prioritizations were aggregated to derive a single prioritization value for agricultural practices for each case study (group decision). In this aggregation phase, each expert type was also assigned an equal weighting within the group decision, again normalized to the unity.

3. Results and Discussion

3.1. Survey Respondents

In total, 54 stakeholders fully responded to the questionnaire, covering all type of stakeholders (

Table 1. Respondents per type of stakeholder.

	Rainfed Cereals	Irrigated Cereals
Total number of respondents	28	26
Farmers	10	9
Technical advisors	7	6
Researchers	5	5
Public agricultural officers	4	4
NGO representatives	2	2

Own elaboration.

). Of those, 28 answered the questionnaire for rainfed cereal production, and 26 the one on irrigated cereal production.

3.2. Perception of Problems and Priorities

Table 2. Assessment of the relevance of different problems (0: very low, 5: Very high).

Problems	Rainfed Cereals			Irrigated Cereals
	Average	Median	Stand. Dev.	Average	Median	Stand. Dev.
Loss of soils organic matter	3.61	4.00	0.99	3.73	4.00	0.92
Loss of profitability/farm abandonment	3.46	4.00	1.45	3.65	4.00	1.32
Excessive use of fertilisers	3.43	3.00	0.84	3.46	3.00	0.86
Excessive use of phytosanitary products	3.18	3.00	0.86	3.31	3.00	0.74
Soil erosion	3.11	3.00	1.20	3.23	3.00	1.14
Water pollution	3.00	3.00	1.33	3.04	3.00	1.37
Excessive water application	-	-	-	2.81	3.00	1.39
Excessive machinery use	2.57	2.50	1.03	2.54	2.50	1.03
Loss of biodiversity	2.35	2.00	1.09	2.38	2.00	1.13
Landscape degradation	2.33	2.00	0.96	2.36	2.00	0.99
Soil pollution	2.29	2.00	1.12	2.31	2.00	1.12
Waterlogged soils	1.39	1.00	1.03	1.38	1.00	1.06

Own elaboration.

summarises stakeholders’ assessment of the severity of different problems for each cereal system. The overall severity perception was relatively low, with similarities between rainfed and irrigated systems and consistency with the characteristics of each cropping system. For both rainfed and irrigated cereal production, the most relevant issue for respondents was the reduction in soil organic matter, closely followed by the decline in profitability (and its associated risk of farm abandonment), and over-fertilization. Conversely, soil waterlogging was perceived as irrelevant, as expected in a relatively dry area. Other issues, such as soil pollution, landscape degradation, and biodiversity loss were also perceived as less severe.

Table 3. Assessment of the priorities for action by cropping system (0: very low, 5: Very high).

Actions	Rainfed Cereals			Irrigated Cereals
	Average	Median	Stand. Dev.	Average	Median	Stand. Dev.
Increase farm profitability	4.37	5.00	5.00	4.32	5.00	1.38
Improve the soil structure	4.32	5.00	5.00	4.31	5.00	1.19
Increase soil fertility	4.25	5.00	5.00	4.23	5.00	1.24
Reduce erosion	4.18	5.00	5.00	4.19	5.00	1.20
Reduce energy consumption	4.14	5.00	5.00	4.15	5.00	1.29
Increase crop yields	3.96	5.00	5.00	3.88	4.50	1.45
Modernisation of agriculture	3.86	4.00	5.00	3.77	4.00	1.21
Increase biodiversity	3.52	4.00	4.00	3.48	4.00	1.23
Increase carbon sequestration	3.38	3.00	3.00	3.42	3.00	1.14
Conserve traditional landscapes	3.04	3.00	4.00	2.92	3.00	1.32
Recover traditional crops	2.54	2.50	2.00	2.54	2.50	1.25
Reduce flooding in fields	2.33	3.00	3.00	2.24	2.00	1.59

Own elaboration.

summarises the priority assigned by stakeholders to different actions to be taken to address agro-environmental problems, i.e., to different objectives for action. Increasing cereal farms’ profitability was the highest priority, closely followed by improving soil conditions (reducing erosion, enhancing soil structure, and increasing fertility). Reducing energy consumption was also given a relatively high priority. These priorities align with the problems assessment in Table 2 and suggest that stakeholders recognize the need to balance soil conservation with economic sustainability by maintaining farm viability, what includes modernizing productive structures and increasing crop yields but also reducing energy and other chemical inputs consumption.

3.3. Suitable Farming Practices

Table 4. Percentage of stakeholders identifying each farming practice as suitable by cropping system.

Farming Practices	Rainfed Cereals (28 Respondents)	Irrigated Cereals (26 Respondents)
Tillage
Minimum tillage	85.71	76.92
No-tillage with chemical weed control	67.86	61.54
Tillage following contour lines	57.14	19.23
Tillage with light implements	46.43	53.85
Conservation tillage with grazing	39.29	23.08
No-tillage with mechanical weed management	21.43	19.23
Soil coverage
Natural vegetation or cover crops	46.43	42.31
Mulching	25.00	34.62
Vegetation strips between crop lines	7.14	7.69
Control of soil erosion
Natural vegetation on the edges of parcels	53.57	42.31
Vegetated erosion barriers	14.29	19.23
Small stonewalls	10.71	7.69
Hedges on the edges of parcels	7.14	7.69
Non-vegetated erosion barriers	3.57	7.69
Fertilisation
Addition of organic matter/manure	82.14	73.08
Combining organic and mineral fertilization	75.00	84.62
Precision agriculture to optimise fertilisation	71.43	80.77
Green manure	67.86	69.23
Use of biostimulants and biofertilizers	10.71	30.77
Pest control
Integrated pest control	85.71	88.46
Crop scheduling and technologies
Crop diversification	85.71	84.62
Changing crop rotations	82.14	73.08
Sprinkler irrigation	-	80.77

Own elaboration.

shows the proportion of respondents deeming each farming practice appropriate for cereal production in the study area, while Tables S1 and S2 (Supplementary Material) summarize the main reasons for not selecting one specific practice. Respondents could select from a predefined list or propose alternatives.

First, minimum tillage was the ploughing alternative chosen as adequate by a vast majority of the respondents, followed by no-tillage with herbicides application (Table 4). For both farming practices, the percentage of respondents was significantly greater for rainfed (86% and 68%, respectively) than for irrigated production (77% and 62%, respectively). This is consistent with current practices, where most rainfed farmers opt for direct sowing to conserve soil moisture and save working time [56,57]. Tillage is one of the most time-consuming (and costly) practices, particularly in rainfed systems, and labour savings can be allocated to complementary activities, such as livestock management [22]. In Mediterranean Spain, direct sowing adoption is more limited in irrigated systems due to technical problems associated with the management of crop residues and soil moisture excess at planting time [13]. Less consensus existed on the use of low intensity tillage implements, with around 50% of respondents considering it a suitable option. Similarly, 57% supported contour tillage as an adequate practice for rainfed cereals, while few endorsed it for irrigated production. Last, only a minority supported no-tillage with mechanical weed control or conservation tillage combined with grazing. Mechanical weed control requires specific tools that farmers rarely own, and they opt to plough, even in organic farms. Farmers are reluctant to grazing due to the risk of increased soil compaction, especially when soil moisture is higher [58].

Reasons for rejecting conservation tillage practices are similar for both cropping systems. Most respondents point out at the lack of tradition with these practices and to the area characteristics. Interestingly, barely no one points at the complexity of tillage practices or the need for technical advice to implement them. These were likely major adoption barriers two decades ago but less so today, with better machinery availability (e.g., better direct seeders), increased use of conservation tillage alternatives in the region, and enough accumulated experience and knowledge [59]. A surprising result is the limited support for contour tillage, despite its effectiveness and simplicity. The rationale for this is that farmers in sloping areas prefer direct seeding, which is perceived as a more effective and less costly alternative for erosion control.

Regarding soil cover practices, none of the three proposed (mulching, vegetation covers, and vegetation strips) were widely endorsed (Table 4). Still, maintaining vegetation covers was deemed suitable for both cropping systems by over 40% of respondents, while vegetation strips were selected by only two. This result is understandable for rainfed production, as cover crops should be planted in summer, with high temperatures and dry soils. However, they could be a good option for summer crops, such as corn, but its penetration among farmers was almost nil. Again, the main reasons for not choosing soil cover practices are lack of tradition and knowledge and incompatibility with the area characteristics (Tables S1 and S2, Supplementary Material), like the aridity that restricts their use in rainfed production.

With respect to barriers to erosion runoff, only keeping natural vegetation on the parcel’s edges was selected by a relatively large proportion of stakeholders (54% in rainfed production and 42% in irrigated) (Table 4). Other options received little support due to their inadequateness for the characteristics of the cropping systems, the lack of local tradition, and, to a lesser extent, doubts about their effectiveness for controlling erosion (Tables S1 and S2, Supplementary Material). Some stakeholders pointed at the investment and maintenance costs of these alternatives, which might explain the preference for maintaining the natural vegetation on the parcel’s edges that does not have any installation cost.

Regarding fertilization, most stakeholders consider the proposed alternatives suitable for the region and cropping systems, except for biostimulants and biofertilizers, which received little support. Plant biostimulants are products that stimulate natural plant nutrition processes to improve nutrient uptake, nutrient use efficiency, abiotic stress tolerance, and/or product quality, but are not traditional fertilizers. They are composed of natural or synthetic substances or by microorganisms (biofertilizers). Organic matter addition, combining mineral and organic fertilizers and precision agriculture techniques were the most selected alternatives. However, some differences exist between cropping systems: adding organic matter was deemed adequate by more stakeholders for rainfed cereals, where soil organic matter content was commonly low, especially in these semiarid Mediterranean systems [60], while combining mineral and organic fertilizers and using precision agriculture techniques were more endorsed for irrigated cereals. Precision agriculture, also called smart farming, uses advanced sensor technologies and data analysis to optimise the use of inputs, such as fertilizers, water, and pesticides, and to improve crop yields and quality. Its penetration in the agricultural sector is still low and is concentrated in high-value productions. Green manure was perceived as adequate by nearly 70% of stakeholders in both systems, despite its rare use, especially in rainfed cereals.

The small proportion of stakeholders that rejected certain fertilization options indicated varied reasons: for rainfed cereals, mainly the lack of tradition and, to a lesser extent, the need for technical advice; for irrigated cereals, concerns about effectiveness and compatibility with cereal cropping in the region, especially regarding the use of organic sources and green manure. The high costs and lack of profitability were also perceived drawbacks of precision agriculture techniques. The main concern with the use of biostimulants and biofertilizers, considered adequate by a minority of stakeholders (11% for rainfed cereals and 31% for irrigated), was the perceived lack of profitability.

A broad consensus exists on integrated pest control techniques, mandatory in the European Union, with more that 85% of stakeholders considering them adequate for both cropping systems. A similar agreement exists on the need to change current crop rotations and diversify cropping systems, with a small minority considering these alternatives inadequate.

3.4. Effectiveness of Farming Practices

Table 5. Effectiveness of farming practices in contributing to more sustainable cropping systems (ranking indexes from the TOPSIS assessment).

Farming Practices	Rainfed Cereals (28 Respondents)	Irrigated Cereals (26 Respondents)
Tillage
Minimum tillage	0.82	0.72
No-tillage with chemical weed control	0.63	0.55
Tillage following contour lines	0.49	0.26
Tillage with light implements	0.46	0.55
Conservation tillage with grazing	0.30	0.21
No-tillage with mechanical weed management	0.27	0.21
Soil coverage
Natural vegetation or cover crops	0.50	0.39
Mulching	0.22	0.22
Vegetation strips between crop lines	0.00	0.00
Control of soil erosion
Natural vegetation on the edges of parcels	0.54	0.50
Vegetated erosion barriers	0.28	0.24
Small stonewalls	0.20	0.11
Hedges on the edges of parcels	0.10	0.14
Non-vegetated erosion barriers	0.11	0.10
Fertilisation
Addition of organic matter/manure	0.92	0.52
Combining organic and mineral fertilization	0.69	0.68
Precision agriculture to optimise fertilisation	0.69	0.82
Green manure	0.67	0.62
Use of biostimulants and biofertilizers	0.31	0.36
Pest control
Integrated pest control	0.77	0.74
Crop scheduling and technologies
Crop diversification	0.74	0.69
Changing crop rotations	0.62	0.55
Sprinkler irrigation	-	0.92

Own elaboration.

shows the TOPSIS analysis results, ranking stakeholders’ preferences for the proposed farming practices. A higher ranking indicates greater perceived effectiveness for a more sustainable cropping in the area. The ranking in Table 5 resembles that in Table 4. However, Table 4 only shows the number of respondents that consider a practice implementable in each cropping system but not its effectiveness to tackle specific problems, as Table 5 does. It must be noted that some practices receive low indexes in the multicriteria assessment despite being considered adequate by many stakeholders, suggesting that they do not consider them very effective. Nevertheless, the results highlight the most effective alternatives.

Minimum tillage ranked highest among tillage alternatives for both rainfed and irrigated cereal production, with relatively high indexes, followed by no-tillage with chemical control of weeds. Both practices received higher indexes for rainfed production, consistently with current regional practice, where minimum tillage prevailed over no-tillage that, in certain conditions, is subject to constrains to its adoption [61].

Regarding soil cover, vegetation covers were ranked as the most effective alternative, with a higher perceived effectiveness for rainfed production. Again, although stakeholders acknowledge their advantages, farmers are still reluctant to implement them. Erosion control alternatives are poorly rated, except for maintaining vegetation on parcel’s edges, which received a moderate ranking.

Fertilization practices effectiveness ranking differed between cropping systems. Adding organic matter/manure was rated as highly effective for rainfed production but much lower for irrigated cereals. For rainfed cereals, the combination of organic and mineral fertilizers, precision agriculture, and green manure scored similarly (indexes between 0.69 and 0.67). For irrigated cereals, precision agriculture ranked highest, followed, at significant distance, by green manure and combined organic/mineral fertilizers. Biostimulants and biofertilizers were considered the least effective fertilization alternative for both systems.

Integrated pest control techniques were rated highly effective for both cropping systems, as was crop diversification. Crop diversification enhances the ecosystem’s natural pest control and lower pesticides application, reducing production costs [32]. For irrigated systems, shifting from furrow to sprinkler irrigation is also considered as very effective.

Overall, the most effective options for addressing agro-environmental threats in Aragon’s cereal production were reducing tillage frequency, using integrated pest control strategies, and promoting crop diversification, consistent with recommendations to enhance both “provision” and “regulation” ecosystems services in agricultural systems [62,63,64,65]. For fertilization, an increased use of organic sources is advised, with stakeholders favouring exogenous organic matter addition in rainfed cereals and precision agriculture and combined fertilization for irrigated cereals. Last, despite the perceived relevance of soil conservation, alternatives like cover crops and vegetated plot edges were largely preferred to more costly barriers for soil erosion control.

3.5. Most Suitable Type of Diversification

Figure 2 shows the respondents’ choice of the most adequate type of diversification for the characteristics of each cereals system. A first relevant result is that none considered intercropping viable for neither rainfed nor irrigated cereal production in the study area (Figure 2), likely because of its low prevalence in Spain, mainly restricted to forage crops in northern Spain (Canter-Martínez, personal communication). Another relevant result is that the preferences differed between cropping systems. While all stakeholders chose crop rotation as the best diversification alternative for rainfed cereals, 62% selected multiple cropping for irrigated cereals and 38% selected crop rotation (Figure 2). Water scarcity constrains the options for crop diversification and intensification in semi-arid rainfed systems, where crop rotation can provide significant diverse benefits [12]. In irrigated systems, the increasing diffusion of sprinkler irrigation enables multiple cropping in arable production systems, allowing the growth of two cash crops per year.

Figure 3 shows the type of diversification chosen for irrigated cereals classified per type of stakeholder. More private technical advisors and researchers preferred crop rotation, while more farmers and all public technical officers and NGO experts considered multiple cropping as the best option for diversification (Figure 3). However, the Fisher’s exact probability test (p = 0.176) allows to accept the null hypothesis of independence among categorical variables (choice of diversification type and stakeholder type), indicating no statistically significant relationship between stakeholder type and diversification preference.

3.6. Most Appropriate Diversification Crops

After selecting their preferred diversification strategy, stakeholders identified the most appropriate crop combinations. Each respondent chose up to two possible combinations out of an open list or indicated alternative combinations. Figure 4 and Figure 5 show the selected crop combinations by diversification type and cropping system. For rainfed production, where all stakeholders prefer crop rotation over other types of diversifications, the most selected rotation is a two-years cycle of winter cereals (wheat or barley) and legumes (vetch or pea), followed by a two-years rotation of winter or spring cereals and fallow (Figure 4). These rotations involve winter crops sown in October–November and harvested in June–July, leaving the soil fallow during summer. Overall, stakeholders have a preference for two-years rotation (61% of stakeholders) over three-years rotations (39%), and for rotating cereals with legumes (45%) rather than with oilseeds (25%) or leaving fallow (30%). The preference for two-years rotations has a primarily economic rationale. In Mediterranean semiarid rainfed systems, barley and wheat dominate, and two-years rotations ensure that the main crop in the rotation (barley or wheat) remains predominant, whereas three-years rotation reduce their proportion. The clear preference for rotating cereals with legumes is linked to their ability to fix nitrogen, reducing the need for chemical fertilization and associated costs, which are a significant expense in cereal production [66]. The lower preference for rotating with oilseeds can be explained by the higher risk of crop failure in more arid areas because of limited soil moisture.

In irrigated production, chosen crop combinations differ significantly from rainfed systems and between crop rotation and multiple cropping alternatives (Figure 5). Preferred crop combinations include corn and alfalfa, which, due to their high water requirements, are not viable under a rainfed regime in the region [67]. The preferred crop rotation is a six-years cycle of alfalfa (four years), followed by corn and wheat, selected by 60% of stakeholders that prefer crop rotation. The second choice is a two-years rotation of corn and winter cereals, with corn planted in April and harvested in October, and winter cereals sown immediately after, to be harvested the following July. Between the harvest of the winter cereal and the planting of the next corn crop, the soil would remain fallow. For multiple cropping, the two preferred combinations are as follows: a double cropping of legumes (pea or vetch) in winter–spring, followed by corn in spring–summer (selected by half of the stakeholders that prefer multiple cropping); and a double cropping of barley in winter–spring, followed by corn in spring–summer (selected by 38% of the stakeholders that prefer multiple cropping). Overall, there is a clear preference for combining winter crops (cereals or legume) with corn rather than with sunflower, a preference likely driven by profitability concerns, as corn is more profitable in the region.

Last, Figure 4 and Figure 5 also show the crop combinations selected by each stakeholder type. In rainfed production, a statistically significant relationship exists between the type of stakeholder and crop rotation choice, should a p < 0.01 threshold be assumed for rejecting the null hypothesis of independence among variables in the Fisher’s test. For example, farmers show a preference for the cereal–fallow rotation, while other stakeholders mostly prefer the two-years winter cereals–legume rotation (Figure 4). In fact, more farmers prefer the three-year wheat–legumes–fallow rotation than the two-years winter cereals–legume rotation. Crop rotations with fallowing were significantly more selected by farmers than by other stakeholders. Although empirical evidence shows limited effectiveness of long-bare fallowing in in NE Spain rainfed systems [22], farmers are still inclined to its use, likely due to past policy incentives. Cropland set-aside was encouraged by EU Common Agriculture Policy between 1988 and 2008. Although legume cropping or forestry alternatives were allowed, fallowing was the predominant use for set-aside area, and farmers became familiar with its use as a rotation alternative. In irrigated cereals, Fisher’s exact probability (p = 0.433) allows to accept the null hypothesis of independence among variables, indicating no statistically significant differences between stakeholder types in the choice of crop combinations, neither for crop rotation nor for double cropping (Figure 5).

4. Conclusions

Our results reflect stakeholders’ perspectives on how to orient cereal cropping systems in the study region towards a more sustainable production. Their consistent identification of key problems and challenges highlights their concern for balancing soil conservation with economic sustainability. This concern is not only expressed by considering farm profitability as a priority objective, but also in their preferences for specific sustainable farming practices and diversification strategies, which reflect a strong consideration of their economic implications. This is evident in their preference for minimum tillage and zero tillage (direct seeding) alternatives that provide both benefits for soil and water conservation and significant savings in time and costs. A similar rationale is behind the preference for crop diversification, cover crops, and maintaining natural vegetation on field borders, which improve soil conditions without the higher costs of non-productive permanent structures like hedgerows, terraces, and stone walls. There is also broad agreement on the need to advance towards a greater use of organic fertilizers and to adopt precision agriculture techniques, especially in irrigated cereal production. Interestingly, biostimulants are not a preferred alternative due to a perceived limited effectiveness and profitability, which might stem from the lack of experience in cereal production.

These results are consistent with empirical evidence and recent participatory experiences in the Mediterranean countries such as Italy, Algeria, Morocco, and Spain, which have demonstrated the potential of practices like intercropping, crop rotations, organic fertilization, reduced tillage, and cover cropping to save inputs, improve soil structure and organic matter content, and reduce greenhouse gas emissions in cereal cropping systems, without compromising yields or grain quality [42,43,44,68].

Regarding crop diversification, stakeholders unanimously expressed preference for crop rotations in rainfed cereal production, due to the area’s arid climate, with two-years rotations with legumes as the best alternative, again reflecting a balance between environmental benefits and profitability. Multiple cropping is the preferred diversification strategy for irrigated systems, with double cropping of corn with either legumes or winter cereals as the preferred combinations.

Additionally, several positive factors emerged from the identification of relevant barriers to the diffusion of sustainable agricultural practices. First, most practices are not considered as difficult to implement or requiring significant technical advice, even for those perceived as less effective. Second, most preferred practices are not considered overly costly or unprofitable, which suggests that there are no financial constraints for their implementation. Last, suggested diversification crops are familiar to farmers. These findings suggest a strong potential for their adoption.

Our findings suggest that policy initiatives aimed at promoting sustainable agricultural practices, such as CAP payments conditionality, agri-environmental measures within Rural Development Plans, or CAP eco-schemes, should be better adapted to local/regional conditions. This requires integrating both scientific evidence and local stakeholders’ knowledge when targeting specific farming practices, whose effectiveness can vary significantly across agricultural systems, based on edaphic, climatic, economic and social differences. Additionally, policies should prioritize sustainable farming practices that maintain or increase farm profitability to ensure benefits that can be sustained in the long-term for both farmers and society. However, it must not be forgotten that some practices that do not directly benefit farmers can increase the provision of essential ecosystem services and thus the society might profit from their subsidisation. In this sense, a distinction should be made between relatively easy-to-implement practices that do not conflict with farm profitability and more complex ones that imply greater changes in the cropping system, require significant investments or pose greater uncertainties to farmers. While the former might only require extension efforts, the latter would require more dedicated efforts in terms of subsidies, tax incentives for investments, and technical support.

To finish, some comments on the limitations of our research must be made. First, although the number of interviewees met the minimum required for this type of analysis, a larger sample would have improved the consistency of the results. Second, the study area is limited to the Aragón Region, which is very representative of the Mediterranean climate and cereal cropping systems but still has its particularities, what somewhat limits the generalizability of our results to other areas. Third, our results are based on stakeholders’ views, supported by their empirical experience and knowledge but also influenced by their subjective beliefs. However, these can be used as a starting point for long-term experimental activities, where the real effectiveness of farming practices and their agronomic, environmental, social, and economic implications could be assessed and the validity of stakeholders’ perceptions could be checked.