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Article

Effects of Microbial and Non-Microbial Biostimulants on Chickpea Growth, Yield, and Soil Properties in a Marginal Mediterranean Environment

by
Daniela Losacco
1,*,
Roberto Puglisi
2,
Carlo Salvemini
3 and
Stefano Convertini
4
1
ReAgri S.r.l., Via Chiatona 62, 74016 Massafra, Italy
2
Department of Agricultural, Forestry, Food and Environmental Sciences (DAFE), University of Basilicata, Via dell’Ateneo Lucano 10, 85100 Potenza, Italy
3
Department of Soil, Plant and Food Sciences, University of Bari “Aldo Moro”, 70125 Bari, Italy
4
Agrin Scarl A.R.L., Via XXV Aprile 13, 36055 Nove, Italy
*
Author to whom correspondence should be addressed.
AgriEngineering 2026, 8(7), 268; https://doi.org/10.3390/agriengineering8070268
Submission received: 17 April 2026 / Revised: 23 June 2026 / Accepted: 26 June 2026 / Published: 30 June 2026
(This article belongs to the Section Sustainable Bioresource and Bioprocess Engineering)
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Abstract

Climate change is increasingly constraining agricultural productivity by intensifying drought, accelerating soil degradation, and increasing pest and disease pressure. In this context, biostimulants are emerging as sustainable tools to improve crop resilience and maintain yield under suboptimal conditions. This study evaluated the effects of microbial and non-microbial biostimulants on chickpea (Cicer arietinum L.) growth, grain yield, seed quality, root traits, and soil properties under low-fertility and water-limited conditions in a marginal field in southern Italy. Treatments included an untreated control and biostimulants based on microelements, arbuscular mycorrhizal fungi (AMF), microbial consortia, ozonated oil, and humic substances. Biostimulants significantly affected agronomic traits. Humic substances increased plant height, while microelements markedly enhanced reproductive performance, with pod number increasing from 13 in the control to 23 pods plant−1. Root traits were also improved, particularly under microbial, humic, and AMF treatments. Grain yield was highest in the ozonated oil treatment (430.6 kg ha−1), whereas seed nutritional composition showed only limited variation among treatments. Biostimulants also induced treatment-specific changes in soil fertility indicators. Overall, the results indicate that selected biostimulants can improve chickpea performance and modulate soil fertility under marginal conditions, although multi-year studies are needed to confirm the stability of these responses under variable environments.

1. Introduction

Modern agriculture is confronted with complex challenges in ensuring global food security amid increasing population pressures and environmental constraints [1]. Although grain legumes are recognized for their pivotal role in sustainable agricultural systems due to their ecological and nutritional benefits, they have experienced comparatively limited expansion in cultivated areas and slower productivity improvements than cereal crops. Chickpea (Cicer arietinum L.) is one of the most significant legume crops in Mediterranean agroecosystems, valued for its high nutritional profile, nitrogen-fixing ability, and low input requirements, particularly in low-fertility environments [2,3]. According to FAOSTAT, global chickpea production reached approximately 16.5 million tonnes in 2023, with India accounting for about 75% of this total [4]. EU chickpea production expanded from around 8000 tonnes in 2014 to approximately 216,000 tonnes in 2018 and continued to increase in subsequent years, exceeding 300,000 tonnes by 2023 according to FAOSTAT data. This growth has been driven by increasing demand for plant-based proteins, renewed interest in sustainable and low-input farming systems, and the rising importance of grain legumes in climate-resilient agricultural strategies, particularly in Mediterranean countries such as Spain, Italy, and France.
In Mediterranean environments, chickpea is typically sown in spring and cultivated under rainfed conditions, making its growth and yield strongly dependent on seasonal rainfall and the soil water retention capacity [5]. With ongoing climatic change, limited water availability is becoming a major constraint to chickpea production. The crop is frequently exposed to drought, particularly during critical stages such as flowering and pod filling, during which water stress can severely reduce yield potential, sometimes by as much as 50% [6].
In response to climate change, adaptive agronomic practices, such as earlier sowing dates, have been adopted to reduce chickpea exposure to heat stress during sensitive growth stages. In addition, innovative approaches such as the use of biostimulants are gaining attention for their potential to enhance plant resilience to abiotic stressors.
Biostimulants are a diverse group of substances and microorganisms that, when applied to plants or the rhizosphere, enhance nutrient use efficiency, tolerance to abiotic stress, and crop quality, independently of their nutrient content [7,8]. Their mode of action differs from that of fertilizers and pesticides, as they act primarily to modulate plant physiological processes. Biostimulants can improve root development, increase photosynthetic activity, and strengthen antioxidant defenses under adverse environmental conditions [9]. According to current classifications, biostimulants include humic and fulvic acids, protein hydrolysates and other nitrogen-containing compounds, seaweed and plant extracts, beneficial fungi (e.g., mycorrhizae), and beneficial bacteria (e.g., Azospirillum and Rhizobium). In the context of climate change, their use represents a promising strategy to support crop productivity and resilience, particularly in rainfed systems such as chickpea cultivation in Mediterranean regions [10]. Gómez et al. [11] demonstrated that biostimulant applications in chickpea improved seed germination and early plant establishment, particularly in the Amelia and IMIDRA 10 varieties. The authors also reported high populations of beneficial soil microorganisms, including nitrogen-fixing bacteria (107 CFU g−1 dry soil) and phosphate-solubilizing bacteria (106 CFU g−1 dry soil), highlighting the potential of biostimulants to enhance nutrient cycling and crop adaptation under environmentally constrained conditions. Recent evidence has also shown that foliar application of biostimulants at flower initiation can significantly enhance chickpea productivity under rainfed conditions by improving nutrient uptake, reproductive performance, and stress tolerance, thereby confirming the potential of biostimulants as sustainable tools for legume cultivation in water-limited environments [12].
Micronutrient-based biostimulants represent an effective strategy for mitigating the negative effects of abiotic stress and improving plant growth [13]. Micronutrients such as zinc (Zn), iron (Fe), boron (B), and molybdenum (Mo) play a crucial role in several physiological and biochemical processes related to stress tolerance and reproductive development. Zinc (Zn) contributes to the regulation of plant water relations and helps preserve cellular water content and osmotic balance under stress conditions. Iron (Fe) is essential for chlorophyll biosynthesis and several metabolic processes involved in plant performance under adverse conditions [14,15]. Similarly, boron (B) is fundamental for plant growth and reproductive development [16], and under stress conditions, it contributes to stomatal regulation and gaseous exchange [17]. Molybdenum (Mo) is an essential micronutrient involved in nitrogen metabolism, as it acts as a cofactor of key enzymes such as nitrogenase and nitrate reductase [18,19]. In legumes, Mo plays a crucial role in biological nitrogen fixation by supporting the activity of nitrogen-fixing bacteria within root nodules, where atmospheric N2 is reduced to ammonia.
Microbial inoculants consist of beneficial microorganisms that enhance nutrient availability, root development, stress tolerance, and overall crop performance. Among these, plant growth-promoting bacteria (PGPB) and arbuscular mycorrhizal fungi (AMF) play a key role in legume cultivation, including chickpea. These microorganisms promote plant growth through nitrogen fixation, phosphate solubilization, phytohormone production, and pathogen suppression. The use of biostimulants to enhance crop productivity and improve plant tolerance to biotic and abiotic stresses has become increasingly widespread in several agricultural systems, including chickpea cultivation. Among the most extensively studied biostimulants are those based on beneficial microorganisms, particularly plant growth-promoting rhizobacteria (PGPR) and symbiotic bacteria of the genus Rhizobium, which can partially replace nitrogen fertilizers through biological nitrogen fixation. In addition, inoculation with rhizobacteria belonging to other microbial genera has also shown positive effects on plant growth, nutrient uptake, and stress tolerance in legumes [20]. In chickpea systems, inoculation with rhizobia (e.g., Mesorhizobium ciceri), AMF, and PGPB such as Azotobacter, Azospirillum, Bacillus, and Pseudomonas has been widely documented to improve nutrient uptake, enhance nodulation, increase biomass, and significantly boost yield [21]. Several studies demonstrate that combining rhizobia with PGPB or AMF leads to synergistic biostimulant effects, improving drought tolerance and nutrient-use efficiency—critical traits for chickpea cultivation in semi-arid environments. For example, co-inoculation of M. ciceri with Pseudomonas fluorescens or Bacillus subtilis has been shown to enhance nodulation, chlorophyll content, and seed yield compared to single inoculation or chemical fertilization alone [22]. Similarly, AMF inoculation improves phosphorus uptake and supports plant performance under low-input conditions [23].
Humic-substance-based biostimulants, comprising humic and fulvic acids derived from the decomposition of organic matter, represent a major class of plant biostimulants that act primarily by modulating plant physiological processes rather than supplying nutrients directly. They are reported to enhance root system architecture, membrane transport processes, photosynthetic activity, and nutrient uptake, as well as improve plant tolerance to abiotic stress, thereby contributing to higher yield and quality in various crops [24].
In chickpea, several studies have shown that the application of humic acid increases pod number, grain yield, and harvest index, including under drought conditions. Moreover, their combined use with mineral nutrients can further enhance crop performance, indicating a positive interaction with conventional fertilization strategies [25]. More recent trials using foliar sprays of humic acid, alone or together with salicylic acid, have shown significant increases in seed protein content and macro- and micronutrient concentrations (K, P, Fe, Zn, Mn), as well as improvements in yield under dryland conditions, highlighting the relevance of humic-based biostimulants for chickpea cultivation in water-limited environments [26].
In modern agriculture, there is a growing interest in sustainable practices that improve crop performance while reducing dependence on synthetic inputs. Biostimulants—including humic substances, protein hydrolysates, algal extracts, micronutrients, and beneficial microorganisms—are gaining attention for their ability to enhance nutrient-use efficiency and stress tolerance. However, their effectiveness remains insufficiently investigated in underutilized crops such as chickpea, particularly under marginal conditions and for locally adapted genotypes.
Beneficial microbes represent a promising biostimulant category, although their field performance is often inconsistent due to environmental variability and limited establishment in soil. Similarly, micronutrient applications (e.g., Zn, B, and Mo) have shown variable effects on biomass and yield, reflecting complex interactions among soil, plant, and climatic factors [27,28]. These limitations highlight the need for further research to clarify the agronomic potential of biostimulants in chickpea cultivation.
Despite growing interest in plant biostimulants, their agronomic effectiveness in chickpea under marginal Mediterranean conditions remains insufficiently documented, particularly when comparing different microbial and non-microbial formulations under the same field conditions. In particular, limited information is available on their combined effects on plant growth, yield components, root traits, seed quality, and soil chemical properties in low-fertility and water-limited environments. Therefore, this study aimed to evaluate the effects of five microbial and non-microbial biostimulant formulations on plant growth, yield performance, and soil properties in a locally adapted chickpea ecotype cultivated under water-limited and low-fertility conditions in southern Italy.

2. Materials and Methods

2.1. Field Trial

The experiment was conducted from February to July 2025 in a marginal field located in Ostuni (Brindisi, Apulia, southern Italy). Before sowing, topsoil subsamples (0–20 cm depth) were collected to evaluate the physical and chemical properties of the soil (Table 1).
The field experiment was conducted using a local chickpea ecotype (Cicer arietinum L.) characterized by a smooth red seed coat (RL-05), cultivated for grain production. As shown in Table 2, five commercial biostimulants, including microbial and non-microbial formulations, were tested in the field experiment: (i) a microelement-based biostimulant (Zn, B, Cu, Mo); (ii) an arbuscular mycorrhizal fungi-based biostimulant; (iii) a microbial biostimulant containing Methylobacterium symbioticum; (iv) an ozonated vegetable oil-based biostimulant; and (v) a humic-substance-based biostimulant. A biostimulant-free control (NT), receiving the same standard agronomic management practices as the other treatments but without biostimulant application, was included in the experiment. The tested biostimulants included: (i) a micronutrient-based formulation containing B (4%), Mo (0.02%), Zn (4.5%), N (4%), and Cu (0.15%), applied at a rate of 2 L ha−1; (ii) an arbuscular mycorrhizal fungi (AMF)-based biostimulant containing 40% symbiotic fungi of the genus Glomus spp. per 100 g of product, applied to soil in dripping mode at 20 kg ha−1; (iii) a microbial biostimulant based on Methylobacterium symbiotum SB23 at a concentration of 3 × 107 CFU g−1, applied as a foliar treatment at 0.5 kg ha−1; (iv) an ozonated oil-based biostimulant containing 85% ozonated sunflower oil, applied as a foliar spray at 1 kg ha−1; and (v) a humic substances-based biostimulant containing 0.5% organic N, 30% organic C, and 90% organic matter on a dry weight basis, applied as a foliar treatment at 2 L ha−1. Biostimulants were applied at BBCH 51, corresponding to inflorescence emergence. The micronutrient-based biostimulant was additionally applied at BBCH 75, corresponding to fruit development. Only the AMF-based biostimulant was applied at transplanting.
The field experiment was arranged as a randomized complete block design with six treatments and three blocks. Each experimental plot measured 10 m × 5 m and represented the experimental unit. Within each plot, plants were randomly sampled as subsamples for plant-level measurements. Plant-level data were averaged at the plot level before statistical analysis to avoid pseudoreplication. All agronomic practices, except for the biostimulant treatments, were uniformly applied across all plots.
Sowing was carried out with a disc seeder at a row spacing of 25 cm, a plant density of 42 plants m−2 (7 cm × 25 cm spacing), and a sowing depth of 4 cm. Plots were randomly assigned within each block. Field fertilization followed a three-step program integrated with macro- and micronutrient formulations. At BBCH 51–59, a balanced NPK fertilizer (20–20–20) with chelated micronutrients was applied. During flowering (BBCH 61–69), an organic carbon-based formulation enriched with mannitol, manganese, and zinc was supplied. At early pod development (BBCH 71), a potassium fertilizer enriched with low-molecular-weight sugars was applied. The fertilization program was uniformly applied to all treatments, including the biostimulant-free control, in order to avoid nutrient deficiency as a confounding factor and to better isolate the effect of the tested biostimulants. Crop protection was carried out using standard fungicide and insecticide treatments, including copper-based and pyraclostrobin fungicides, and Bacillus thuringiensis and tau-fluvalinate for insect control, applied according to label recommendations. All products were applied at label-recommended doses, and crop protection practices were maintained throughout the entire growing cycle. No irrigation was applied during the crop cycle; therefore, the experiment was conducted under rainfed and water-limited conditions (Table 3).

2.2. Site Characterization with UAV and GIS Analysis

The study area was selected using an integrated approach combining environmental, pedological, and climatic analyses supported by Geographic Information System (GIS) tools to identify suitable areas for chickpea cultivation under water-limited conditions [29,30]. Spatial data processing, harmonization, and map generation were performed using QGIS software (version 3.44, QGIS Development Team, Switzerland). UAV-based imagery was acquired using a DJI Mavic 3 Multispectral (DJI, Shenzhen, China), equipped with one 20 MP RGB sensor and four 5 MP multispectral sensors (green, red, red edge, and near-infrared). The orthomosaic was processed with Agisoft Metashape Professional (Educational version, Agisoft LLC, St. Petersburg, Russia).
Soil properties, including soil texture, effective depth, organic matter content, water-holding capacity, and pH, were evaluated to assess soil suitability. Climatic data, including mean annual temperature, precipitation, relative humidity, and solar radiation, were collected from local meteorological stations and the ARPA Puglia database [31]. Land use classification was carried out to identify areas with high suitability for legume cultivation. All datasets were integrated within a GIS environment, where spatial interpolation and a multi-criteria analysis (MCA) approach were applied to evaluate site suitability (Figure 1). Overlay analysis of pedological, climatic, and land use layers enabled the identification of areas characterized by water-limited conditions and suitable for chickpea cultivation. This approach enabled the identification and selection of the most suitable sites for subsequent field experimentation.

2.3. Plant Sampling, Agronomic Characterization, and Yield

Plant growth and yield parameters were monitored at regular phenological stages throughout the experimental period. At key phenological stages (inflorescence emergence, inflorescence development, and harvest), 15 plants per treatment were randomly selected for the agronomic analyses. The measured variables included plant height, number of basal shoots, leaf chlorophyll status (SPAD index; PhotosynQ MultispeQ v2.0, East Lansing, MI, USA), pod weight, pod length, number of seeds per pod, and seed weight per pod. At harvest, root morphological traits—root dry weight, total root length, average root diameter, and root surface area—were quantified using digital image analysis (ImageJ software, version 1.54). Grain yield was determined at the plot level by harvesting the central area of each plot, excluding border rows to minimize edge effects. Harvested seeds were cleaned and weighed, and grain yield was expressed as kg ha−1. Plot-level yield values were used for statistical analysis. Seed moisture correction was not applied; therefore, yield values refer to seed weight at harvest moisture. At the end of the experiment, chickpea flour samples obtained from each treatment were analyzed to determine their chemical composition. The percentages of fat, moisture, fiber, starch, protein, and ash were quantified using near-infrared reflectance spectroscopy (NIRS) with a FOSS NIR System 2500 (FOSS Analytical, Hillerød, Denmark). Samples were scanned in reflectance mode, and compositional parameters were predicted using the instrument’s internal calibration models. All measurements were expressed as percentages (%).

2.4. Soil Physicochemical Analysis

Soil physicochemical analyses were performed on composite rhizosphere soil samples collected from each replicate. Five subsamples were randomly collected from the rhizosphere of each replicate and combined to obtain a representative composite sample. The samples were air-dried, sieved through a 2 mm mesh, and subjected to physicochemical characterization. Soil pH and electrical conductivity (EC) were measured in soil–water suspensions using standard procedures. Total carbon and soil organic matter were determined according to established laboratory methods. The concentrations of macro- and micronutrients (P, K, Ca, Mg, Na, Fe, Mn, Cu, Zn, and B) were quantified using standard analytical procedures. Samples were collected from the 0–20 cm soil layer.

2.5. Statistical Analysis

All statistical analyses were performed using OriginPro 9.0 (64-bit) software (OriginLab Corporation, Northampton, MA, USA). Data were analyzed according to a randomized complete block design (RCBD). Treatments were considered fixed effects, while blocks were included in the model to account for field variability. The experimental unit was the plot. For plant-level measurements, individual plants were treated as subsamples and averaged within each plot before analysis to avoid pseudoreplication. Analysis of variance (ANOVA) was used to evaluate the effects of treatments on agronomic parameters, root traits, grain yield, seed composition, and selected soil chemical properties. When treatment effects were significant, mean comparisons were performed using Tukey’s honestly significant difference (HSD) test at p ≤ 0.05. Significance was declared at p ≤ 0.05, p ≤ 0.01, and p ≤ 0.001, where appropriate. Principal component analysis (PCA) was conducted on standardized soil chemical variables to explore multivariate relationships among soil properties and identify treatment-related patterns.

3. Results

3.1. Effects of Biostimulant Treatments on Chickpea Growth, Yield Components, and Seed Nutritional Quality

Biostimulant treatments significantly influenced several chickpea growth and yield traits compared with the biostimulant-free control (Figure 2). The main treatment effects were observed for plant height, pod number, pod weight, seed number, and seed weight, whereas shoot number remained unchanged across treatments. Plant height was significantly increased in humic-substance-based biostimulant-treated plants (37.8 cm) compared to the biostimulant-free control (29.3 cm). In comparison, intermediate values were observed for chickpea treated with ozonated oil-based biostimulant (34.3 cm) and arbuscular mycorrhizal fungi-based biostimulant (33.06 cm).
As shown in Table 4, reproductive traits were significantly affected by the tested biostimulant treatments. The microelement-based treatment showed the strongest effect on pod number and seed number, while AMF and ozonated oil increased pod weight. Humic substances were associated with the highest pod length. Seed weight was generally higher in treated plants than in the biostimulant-free control, indicating an overall positive effect of biostimulant application on reproductive performance. These improvements in yield-related traits may be associated with enhanced nitrogen uptake and utilization in biostimulant-treated plants, potentially leading to improved nitrogen use efficiency and greater allocation of assimilates to seed development.
Biostimulant treatments significantly affected SPAD values at flowering. The highest SPAD values were recorded in microelement-based biostimulant-treated plants (14.98), which were significantly higher than those observed in the biostimulant-free control (9.9). Similarly, the application of AMF (13.78) and humic substances (13.8) showed significantly higher SPAD values compared to the biostimulant-free control, while ozonated vegetable oil-based biostimulant (13.4) also resulted in increased chlorophyll content, although with slightly lower significance (p < 0.01). In contrast, microbial-based treatment (8.9) did not differ significantly from the control, indicating no effect on leaf chlorophyll content. Overall, most biostimulant treatments enhanced SPAD values, suggesting improved chlorophyll content and potentially higher nitrogen assimilation efficiency during the reproductive stage.
Under water-limited conditions, significant differences among treatments were observed for root dry weight, root length, and root surface area. Root dry weight was markedly affected by treatments (p < 0.001), with all biostimulant applications significantly increasing root biomass compared to the biostimulant-free control (87 ± 2.4 g). The highest values were observed in the treatment based on microbial biostimulant (195 ± 3.2 g), humic substances (191 ± 3.5 g), and AMF (182 ± 2.8 g), followed by biostimulant based on microelements (162 ± 3.7 g), while ozonated vegetable oil-based biostimulant showed a more limited increase (115 ± 4.4 g). Root length was also significantly influenced by treatments (p < 0.05), although differences among treatments were less pronounced. The highest values were recorded in AMF (4.3 ± 1.7 cm) and humic substances (4.1 ± 2.2 cm), followed by microelement-based biostimulant (3.9 ± 2.1 cm), ozonated vegetable oil-based biostimulant (3.7 ± 1.8 cm), and microbial biostimulant (3.6 ± 1.9 cm), while the lowest value was observed in the biostimulant-free control (2.8 ± 0.9 cm). Root Surface Area (RSA) was strongly affected by treatments (p < 0.001). AMF showed a significantly higher RSA (5.5 ± 1.9 cm2) compared to all other treatments and the control (1.3 ± 1.7 cm2). The remaining treatments (ELE: 1.9 ± 1.4 cm2; BIO: 1.7 ± 1.4 cm2; OZO: 1.5 ± 0.9 cm2; HS: 2.3 ± 1.4 cm2) did not show statistically significant differences among each other, indicating a limited effect on root surface expansion (Figure 3). Overall, while all treatments enhanced root biomass, only AMF significantly improved root surface area, suggesting a specific effect on root functional traits rather than a general increase in root mass.
Chickpea yield performance was assessed by comparing grain yield (GY) among treatments with that of the biostimulant-free control (Table 5). Biostimulant treatments significantly affected grain yield (p < 0.05). The highest yield was observed in ozonated vegetable oil-treated plants (430.6 kg ha−1), which was significantly higher than AMF (339.2 kg ha−1; p < 0.05) and showed an increasing trend compared to the biostimulant-free control (375.1 kg ha−1). Biostimulant based on microelements also resulted in relatively high yield values (404.3 kg ha−1), although differences with the control were not always statistically significant. Conversely, AMF treatment showed the lowest grain yield among all treatments. Humic substances and treatment based on microbial biostimulant produced intermediate values, not significantly different from the biostimulant-free control. This response indicates that the improvement in root surface area and soil nutrient availability observed under AMF treatment did not translate into higher grain yield under the specific environmental conditions of the present trial.
The nutritional composition of chickpea seeds was evaluated in terms of fat, moisture, fiber, starch, protein, and ash content. Overall, biostimulant treatments resulted in slight variations in seed composition compared with the biostimulant-free control, while values remained within the typical range reported for chickpea. Fat content showed limited variability among treatments, ranging from 5.61% (humic substances) to 6.24% (arbuscular mycorrhizal fungi-based biostimulant). Similarly, fiber content remained relatively stable across treatments, with values between 6.43% and 6.81%. Moisture content was slightly higher in treated samples, particularly in biostimulant based on microelements (11.83%) and AMF treatments (11.57%), compared to the biostimulant-free control (10.85%). Starch content varied moderately, with the highest values observed in AMF-treated plants (50.56%) and untreated samples (50.1%), while lower values were recorded in microelement-based treatments (46.52%). Protein content showed minor differences among treatments, ranging from 18.31% (microelements) to 19.30% (AMF), indicating that biostimulant application had a limited impact on seed protein accumulation. Ash content exhibited slight increases in treated samples, particularly in microelement-based (2.98%) and humic substances treatments (2.91%), compared to the biostimulant-free control (2.57%). Overall, biostimulant application did not markedly alter seed nutritional composition, although some treatments showed trends toward increased mineral content and slight modulation of carbohydrate fractions. Grain yield was significantly affected by treatment. The highest value was recorded in the ozonated oil treatment, which differed significantly from AMF and showed a positive trend compared with the biostimulant-free control. The microelement-based treatment also produced relatively high yield values, whereas humic substances and the microbial treatment showed intermediate responses.

3.2. Effects of Biostimulant Treatments on Soil Chemical Properties After Chickpea Cultivation

Biostimulant treatments affected several soil chemical properties at the end of the chickpea growing season (Table 6). Soil pH remained relatively stable across treatments, ranging from 7.9 to 8.1, indicating that biostimulant application did not significantly affect soil acidity. Similarly, cation exchange capacity showed moderate variation among treatments, with slightly higher values observed in treatments based on Methylobacterium symbioticum and microelements compared to the biostimulant-free control. Nutrient availability was differentially affected by the biostimulant treatments. In particular, the AMF treatment showed higher phosphorus and potassium levels, suggesting enhanced nutrient mobilization in the rhizosphere (Table 5). This treatment was also associated with increased micronutrient concentrations, indicating an overall improvement in nutrient availability. Nitrogen content was slightly higher in the microbial and ozonated oil-based treatments compared to the biostimulant-free control, while treatments based on microelement and humic treatments showed intermediate values. Soil organic carbon and organic matter were highest in the ozonated oil-treated soils, suggesting a positive effect on soil organic matter accumulation. The multivariate analysis further highlighted treatment-specific effects on soil properties (Figure 4). Principal component analysis (PCA) biplot revealed a clear separation among treatments based on soil chemical properties. The AMF treatment was associated with higher phosphorus, potassium, and magnesium levels, indicating enhanced nutrient mobilization. Ozonated oil and humic treatments were related to higher organic matter and calcium carbonate content, suggesting improvements in soil quality. The microbial treatment was associated with nitrogen dynamics, whereas the biostimulant-free control was located near the origin, representing baseline soil conditions.

4. Discussion

In the present study, five different biostimulants were applied to evaluate the effect of these new green products on plant growth under abiotic stress conditions, such as water stress. Specifically, we evaluated the efficacy of three non-microbial biostimulants (microelements, ozonated vegetable oil, and humic substances) and two microbial biostimulants (Arbuscular Mycorrhizal Fungi and Methylobacterium symbioticum) in vegetative parameters, yield, chickpea seed quality, and soil chemical-physical characteristics.
The present study indicates that biostimulant application can enhance chickpea growth, selected yield traits, and some soil properties under water-limited and low-fertility conditions. These effects should be interpreted in the context of the environmental conditions observed during the growing season, which was characterized by extremely low precipitation and gradually increasing temperatures. During the reproductive stages (June–July), temperatures reached up to 32.5 °C, and severe drought stress was imposed by the lack of rain from April onwards (Table 3). Under these conditions, crop performance was primarily driven by plants’ ability to maintain physiological activity and nutrient uptake despite limited water availability.
Biostimulant-treated plants showed higher SPAD index values and improved yield components, indicating enhanced chlorophyll content and photosynthetic activity. Similarly, studies by Eleiwa et al. and Mbarki et al. have highlighted an increase in photosynthetic pigments and the health status of crop plants [32,33]. SPAD is widely recognized as a proxy for plant nitrogen status, and its increase suggests improved nitrogen assimilation and nitrogen use efficiency (NUE), particularly under stress conditions where nutrient uptake is typically impaired [34]. These findings support the hypothesis that biostimulants can mitigate drought-induced limitations on nitrogen metabolism by sustaining plant physiological performance [8].
Among the treatments, microelement-based biostimulants resulted in the highest yield performance, particularly in pod number, seed number, and seed weight. This effect may be attributed to micronutrients such as zinc and boron, which regulate enzymatic processes involved in nitrogen metabolism, reproductive development, and assimilate partitioning. Exogenous applications of Zn, B, and other micronutrients may modulate plant biochemical responses by enhancing the activity of antioxidant enzymes, as previously reported [35,36,37]. In addition, exogenous nutrient supply has been shown to stimulate chlorophyll biosynthesis, delay leaf senescence, and promote nutrient biofortification, ultimately leading to improved photosynthetic performance and increased activity of photosynthetic enzymes [38]. Moreover, Zn plays a key role in regulating plant water relations, contributing to heat stress tolerance by maintaining cellular water status and osmotic balance. Likewise, adequate boron availability supports stomatal function, thereby improving gas exchange under stress conditions [39,40]. In agreement with the findings of Venugopalan et al. [41], the combined application of Zn, Fe, and B has been shown to enhance chlorophyll biosynthesis, photosynthetic activity, gas exchange, and osmotic regulation, thereby alleviating stress conditions and improving yield in late-sown lentil. In the present study, a similar trend was observed in chickpea, where the application of micronutrient-based biostimulants resulted in a clear yield improvement compared to the biostimulant-free control. Yield increased from 375 kg ha−1 in untreated plants to 404.3 kg ha−1 in treated plants. This enhancement in productivity was further supported by a significant increase in the average number of seeds per pod, from 14 in the control to 34 with biostimulant application. These results suggest that micronutrient-based treatments can effectively improve yield components and overall crop performance, likely through mechanisms related to improved physiological and biochemical processes.
Biostimulants based on microorganisms and arbuscular mycorrhizal fungi (AMF) represent a promising tool for enhancing yields and plant resilience under changing climatic conditions. However, their use remains limited in legume production because both the soil microbiome and poor environmental conditions often constrain the efficiency of microbial biostimulants [42]. AMF treatment had a pronounced effect on root system architecture, significantly increasing root surface area and nutrient availability, particularly phosphorus and potassium. The enhancement of root traits confirms the known role of arbuscular mycorrhizal fungi in improving soil exploration and nutrient uptake under drought conditions [43]. Although AMF application improved root surface area and was associated with higher soil phosphorus and potassium availability, this treatment resulted in the lowest grain yield among all tested biostimulants. This apparent discrepancy may indicate that the enhanced root development and nutrient mobilization did not fully translate into reproductive efficiency under the specific environmental conditions of the experiment. Under severe water-limited conditions, the carbon cost associated with maintaining the symbiotic relationship between the host plant and AMF may have partially reduced the allocation of assimilates to pod and seed development. In addition, the effectiveness of AMF symbiosis can be strongly influenced by environmental factors, soil conditions, and host plant physiological status, leading to variable effects on final crop productivity. The yield of chickpea was reduced under water-deficit stress conditions. Turgor pressure is reduced by drought stress, which results in decreased cell expansion and impaired growth of plant organs. Furthermore, the reduced accumulation of photoassimilates and the limited mobilization of elements during growth result in a smaller number of flowers and fruits, thus resulting in a reduction in yield [44].
This study highlights the differential effects of various biostimulants on chickpea performance, including a foliar organic product based on Methylobacterium. The results highlight that this biostimulant significantly increased seed number and weight compared to the biostimulant-free control, indicating a positive effect on reproductive efficiency rather than on vegetative growth or pod formation. The increase in seed number (+78% compared with the biostimulant-free control, Table 3) and the high seed weight observed under microbial biostimulant application suggest improved assimilate partitioning and seed filling processes. This is consistent with previous findings reporting that Methylobacterium spp. act as plant growth-promoting bacteria (PGPB), enhancing plant performance through physiological mechanisms such as phytohormone production, improved nitrogen metabolism, and stress mitigation [45]. In particular, their ability to colonize the phyllosphere and utilize methanol emitted by leaves allows a direct interaction with plant metabolism, potentially leading to increased photosynthetic efficiency and delayed senescence [46]. Unlike other treatments, microbial biostimulant containing Methylobacterium symbioticum did not significantly affect pod number or plant height, suggesting that its mode of action is more closely related to metabolic regulation than to structural plant development. Similar trends have been observed in other crops, where foliar application of Methylobacterium symbioticum improved nitrogen use efficiency and yield components without markedly altering plant architecture [47,48]. This is particularly relevant in legumes such as chickpea, where yield is strongly influenced by seed set and filling rather than by biomass accumulation. The observed increase in root biomass following microbial application suggests a stimulatory effect on root system development, which is consistent with the known ability of plant growth-promoting bacteria, including Methylobacterium spp., to enhance root architecture through phytohormone production (particularly auxins) and improved nutrient acquisition. Similar effects have been reported in several crops, where microbial biostimulants promoted root elongation, lateral root formation [49], and overall root biomass, ultimately contributing to improved plant performance. Despite the observed improvements in root biomass and seed-related traits, the application of the microorganism-based biostimulant did not result in a significant increase in grain yield compared to the untreated control. This response is consistent with previous studies indicating that biostimulant-induced enhancements in plant physiology do not always translate into yield gains, as final productivity is strongly influenced by environmental conditions and resource availability [8,50]. In particular, under limited water availability, the potential benefits of improved root development and metabolic activity may have been constrained, thereby reducing their effect on final yield formation. This interpretation is consistent with previous studies showing that biostimulant-induced physiological improvements do not always result in significant yield increases under severe environmental constraints.
The application of ozonated oil significantly increased yield and SPAD value compared to the control, indicating improved photosynthetic activity and plant physiological status under water-limited conditions. The positive effects on pod and seed weight suggest an overall enhancement of reproductive efficiency. These responses may be related to the ability of ozonated compounds to induce mild oxidative signaling, activating plant defense mechanisms and improving tolerance to abiotic stress. Under drought conditions, this effect likely contributed to maintaining chlorophyll content and delaying senescence. Although ozonated oils are mainly used for plant protection, their role as biostimulants remains largely unexplored. Therefore, this study provides novel evidence of their potential in sustainable agriculture, particularly under water stress conditions [8,51].
The application of humic substances significantly influenced vegetative growth, particularly plant height and pod length, confirming their role as plant biostimulants. These effects are mainly attributed to their capacity to stimulate root system development, enhance nutrient uptake, and exert hormone-like activity, especially auxin-like effects that promote cell elongation and plant growth [52,53]. Under the water-limited conditions of the present study, the positive response observed in vegetative traits suggests an important role of humic substances in improving plant adaptation to drought stress. Several studies have demonstrated that humic substances can enhance water use efficiency, improve root hydraulic conductivity, and regulate stomatal behavior, thereby mitigating the negative effects of water deficit [34,54]. In legumes such as chickpea, the beneficial effects of humic substances may also involve improved nutrient dynamics and interactions with soil microbiota, contributing to enhanced nitrogen metabolism and plant vigor [55]. Humic substances are widely recognized as multifunctional biostimulants whose effects on crop performance are often indirect. Their application primarily improves soil physicochemical properties, microbial activity, and plant physiological processes, resulting in enhanced nutrient use efficiency and increased tolerance to abiotic stress, rather than directly increasing yield [56,57].
Biostimulants application changed soil chemical properties, except for pH. This stability is consistent with recent studies indicating that biostimulants generally do not directly alter soil pH in calcareous soils but rather influence nutrient dynamics and microbial activity [58]. Among treatments, arbuscular mycorrhizal fungi (AMF) significantly enhanced phosphorus, potassium, and micronutrient availability. Recent studies have demonstrated that AMF can increase P solubilization and micronutrient uptake under low-input or stress conditions [59]. The higher levels of Fe and Cu observed in this study further support the ability of AMF to improve micronutrient bioavailability in the rhizosphere. Microbial and microelement-based treatments showed similar clustering patterns, mainly influencing nitrogen content and soil fertility. The increase in total nitrogen in soils treated with Methylobacterium symbioticum is, according to recent works, highlighting the role of plant growth-promoting bacteria in enhancing nitrogen cycling and availability, either through biological fixation or stimulation of soil microbial processes [60]. These effects are particularly relevant in legume-based systems, where interactions between soil microbes and plant nitrogen metabolism can influence both soil fertility and crop performance. Interestingly, the ozonated vegetable oil treatment was strongly associated with higher soil organic carbon and organic matter content. Although the use of ozonated compounds in soil management is still poorly explored, recent studies suggest that oxidative products may stimulate microbial turnover and organic matter stabilization processes, potentially enhancing carbon accumulation in soil [61]. In Figure 4, the PCA highlighted treatment-specific effects, confirming that different biostimulants act through distinct mechanisms. AMF primarily enhanced nutrient availability, ozonated oil improved soil organic matter accumulation, and microbial treatments influenced nitrogen dynamics. These findings are consistent with recent literature emphasizing that biostimulants should be considered function-specific tools rather than universal inputs, with effects strongly dependent on their composition and mode of action [8].
Overall, the results show that the tested biostimulants affected chickpea performance and soil properties through treatment-specific responses. AMF mainly enhanced root functional traits and nutrient mobilization; the microbial treatment was more closely associated with root biomass and nitrogen dynamics; humic substances promoted vegetative growth; and microelements and ozonated oil had the most evident effects on reproductive performance and yield. These findings support the idea that biostimulants should not be considered interchangeable products, but rather function-specific tools whose effectiveness depends on formulation, crop response, and environmental conditions.

5. Conclusions

This study demonstrates that biostimulant application represents a promising strategy to support chickpea cultivation under low-fertility and water-limited conditions. The tested formulations showed different functional responses: microelement-based and ozonated oil-based treatments were the most effective in improving reproductive performance and grain yield, whereas AMF mainly enhanced root architecture and nutrient availability. Microbial and humus-substance-based products also promoted selected root and vegetative traits, although their effect on final yield was more limited. In addition to crop responses, several treatments induced changes in soil chemical properties, suggesting a potential contribution to soil fertility under marginal conditions. Overall, the results highlight the importance of selecting biostimulants according to their specific mode of action and agronomic objective. Further multi-year and multi-environment trials are needed to verify the stability of these responses and define the most suitable application strategies for chickpea-based systems.

Author Contributions

Conceptualization, D.L.; methodology, D.L., C.S. and R.P.; validation, D.L., R.P. and S.C.; formal analysis, D.L., C.S. and R.P.; investigation, D.L. and R.P.; resources, S.C.; data curation, D.L., C.S. and R.P.; writing—original draft preparation, D.L.; writing—review and editing, D.L., C.S. and R.P.; visualization, D.L., C.S. and R.P.; supervision, D.L. and S.C.; project administration, S.C.; funding acquisition, S.C. All authors have read and agreed to the published version of the manuscript.

Funding

This research was funded by the project “NBFC “National Biodiversity Future Center”—Progetto per il ripristino, la tutela e la valorizzazione di un Biotipo di Cece autoctono pugliese attraverso la produzione di prodotti da forno innovativi con proprietà antinfiammatorie e antitumorali—NBFC_S8PMI_1028—Missione 4 Istruzione e ricerca—Componente 2 dalla ricerca all’impresa—Investimento 1.4, finanziato dall’Unione europea—NextGenerationEU—Pro.Bi.Ce. (Codice Progetto CN00000033—CUP B17H24003010004)”.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

Data is contained within the article.

Acknowledgments

Thanks to the team of ReAgri S.r.l. for carrying out the research project. Thanks to Pasquale Mariano Carmignano for coordinating the research project. Thanks to Francesco Acquasanta, Fabio Fedele, Nicola Tinella, Giovanni Perrone, Gaetano Terzuoli, Flavio Saccomanno, and Cosimo Bernalda for the agronomic management of the experimental field, sowing, and seed harvesting. Thanks to Giovanni Perrone and Gaetano Terzuoli for collecting the vegetative parameters of the field. The authors have reviewed and edited the output and take full responsibility for the content of this publication.

Conflicts of Interest

Daniela Losacco and Stefano Convertini were employed by the company ReAgri S.r.l., Massafra, Italy and Agrin Scarl A.R.L., Nove, Italy. The remaining authors declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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Figure 1. GIS-based identification of the chickpea experimental field using QGIS, located in a marginal area characterized by low rainfall and water-limited conditions in southern Italy.
Figure 1. GIS-based identification of the chickpea experimental field using QGIS, located in a marginal area characterized by low rainfall and water-limited conditions in southern Italy.
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Figure 2. Representative chickpea plants collected from each treatment at harvest.
Figure 2. Representative chickpea plants collected from each treatment at harvest.
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Figure 3. Root surface area (cm2) of chickpea plants under different biostimulant treatments. Bars represent mean values; n = 15 plants per treatment group. Different lowercase letters indicate significant differences among treatments according to Tukey’s HSD test (p ≤ 0.05).
Figure 3. Root surface area (cm2) of chickpea plants under different biostimulant treatments. Bars represent mean values; n = 15 plants per treatment group. Different lowercase letters indicate significant differences among treatments according to Tukey’s HSD test (p ≤ 0.05).
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Figure 4. Principal component analysis (PCA) biplot showing the distribution of treatments and soil chemical variables. Each point represents the mean value of a treatment across field plot replicates, whereas arrows indicate the contribution and direction of the soil variables to the principal components. The plot highlights the differential effects of biostimulants on soil properties, with distinct clustering patterns associated with nutrient availability and organic matter dynamics.
Figure 4. Principal component analysis (PCA) biplot showing the distribution of treatments and soil chemical variables. Each point represents the mean value of a treatment across field plot replicates, whereas arrows indicate the contribution and direction of the soil variables to the principal components. The plot highlights the differential effects of biostimulants on soil properties, with distinct clustering patterns associated with nutrient availability and organic matter dynamics.
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Table 1. Soil properties in the 0–20 cm depth layer before sowing.
Table 1. Soil properties in the 0–20 cm depth layer before sowing.
ParametersValue
Sand (20–2000 µm)52.6
Silt (2–20 µm)36.5
Clay (2 µm)10.9
Electrical conductivity (mS cm−1)0.16
Calcium carbonate (g kg−1)177
Total nitrogen (g kg−1)1.7
Organic matter content (%)3
Phosphorus (mg kg−1)6
Potassium (mg kg−1)280
Ca (g kg−1)4.8
Mg (mg kg−1)216
Na (mg kg−1)84
Cation exchange capacity (meq/100 g)27
Iron (mg kg−1)4
Boron (mg kg−1)1
Manganese (mg kg−1)9
Copper (mg kg−1)1
Zinc (mg kg−1)0.33
C/N ratio11
Table 2. Types of biostimulants tested in the field experiment.
Table 2. Types of biostimulants tested in the field experiment.
Treatment
Code		Treatment
Type		Main
Components/
Composition		DoseApplication
Method		Application
Timing
NTBiostimulant-free controlNo biostimulant---
ELEMicronutrient-based
biostimulant		B 4%, Mo 0.02%,
Zn 4.5%, N 4%,
Cu 0.15%		2 L ha−1Foliar applicationBBCH 51 and BBCH 75
AMFArbuscular
mycorrhizal fungi-based
biostimulant		40% symbiotic fungi of the genus
Glomus spp. per 100 g of product		20 kg ha−1Soil application in dripping modeAt transplanting
BIOMicrobial
biostimulant		Methylobacterium symbioticum SB23, 3 × 107 CFU g−10.5 kg ha−1Foliar applicationBBCH 51
OZOOzonated vegetable oil-based biostimulant85% ozonated
sunflower oil		1 kg ha−1Foliar sprayBBCH 51
HSHumic-substance-based
biostimulant		0.5% organic N, 30% organic C, and 90% organic matter on a dry weight basis2 L ha−1Foliar applicationBBCH 51
Table 3. Average mean temperature (MTT), average minimum temperature (MTN), average maximum temperature (MTX), rainfall, and relative humidity (RH) during the field experiment.
Table 3. Average mean temperature (MTT), average minimum temperature (MTN), average maximum temperature (MTX), rainfall, and relative humidity (RH) during the field experiment.
MonthMTT (°C)MTN (°C)MTX (°C)Rainfall (mm)RH (%)
Jan12.18.915.33.5681.2
Feb11.58.314.82.2678.7
Mar13.910.717.03.2275.3
Apr15.912.119.70.4266.1
May19.715.723.71.6262.3
Jun26.922.231.6048.8
Jul28.223.832.5033.6
Table 4. Effect of treatments (biostimulant-free control, NT; microelement-based biostimulant, ELE; arbuscular mycorrhizal fungi-based biostimulant, AMF; microbial biostimulant, BIO; ozonated vegetable oil-based biostimulant, OZO; humic-substance-based biostimulant, HS) under deficit irrigation on chickpea growth. Values are means; n = 15 chickpea plants per treatment. Different lowercase letters within the same column indicate significant differences among treatments according to Tukey’s honestly significant difference (HSD) test at p ≤ 0.05. ns = not significant; *** = p ≤ 0.001.
Table 4. Effect of treatments (biostimulant-free control, NT; microelement-based biostimulant, ELE; arbuscular mycorrhizal fungi-based biostimulant, AMF; microbial biostimulant, BIO; ozonated vegetable oil-based biostimulant, OZO; humic-substance-based biostimulant, HS) under deficit irrigation on chickpea growth. Values are means; n = 15 chickpea plants per treatment. Different lowercase letters within the same column indicate significant differences among treatments according to Tukey’s honestly significant difference (HSD) test at p ≤ 0.05. ns = not significant; *** = p ≤ 0.001.
TreatmentsPlant Height (cm)Shoots NumberPod NumberPod Weight (g)Pod Length (cm)Seeds NumberSeeds Weight (g)
NT29.3 ± 4.2 c3 ± 0.0013 ± 1.5 c27.96 ± 4.6 c2.99 ± 0.2 c14 ± 0.07 d23.22 ± 2.7 c
ELE32.3 ± 4.2 b3 ± 0.0023 ± 1.3 a27.92 ± 2.5 c3.3 ± 0.3 b34 ± 0.04 a39.91 ± 2.1 a
AMF33.06 ± 4.3 b3 ± 0.0017 ± 1.7 b37.04 ± 3.8 a3.15 ± 0.3 bc20 ± 1.2 c35.67 ± 3.00 b
BIO31.6 ± 4.6 ab3 ± 0.0017 ± 2.7 b27.44 ± 4.5 c2.99 ± 0.3 b25 ± 0.09 b36.63 ± 3.8 a
OZO34.3 ± 4.5 ab3 ± 0.0019 ± 2.1 ab35.6 ± 4.3 a3.3 ± 0.3 b22 ± 0.03 c36.76 ± 2.4 ab
HS37.8 ± 4.1 a3 ± 0.0018 ± 3.1 b31.1 ± 4.5 b6.3 ± 0.3 a21 ± 1.6 c35.7 ± 2.1 b
p < 0.001***ns***************
Table 5. Effects of biostimulant treatments on chickpea grain yield (kg ha−1). Different letters indicate significant differences among treatments according to Tukey’s HSD test (p ≤ 0.05).
Table 5. Effects of biostimulant treatments on chickpea grain yield (kg ha−1). Different letters indicate significant differences among treatments according to Tukey’s HSD test (p ≤ 0.05).
TreatmentsGrain Yield (kg ha−1)
NT375.1 ± 80.2 bc
ELE404.3 ± 109.5 ab
AMF339.2 ± 48.7 c
BIO378.8 ± 60.2 bc
OZO430.6 ± 34.5 a
HS382.4 ± 92.6 bc
Table 6. Soil chemical properties as affected by biostimulant treatments at the end of chickpea cultivation. Values represent composite soil samples collected from each treatment at the end of the experiment.
Table 6. Soil chemical properties as affected by biostimulant treatments at the end of chickpea cultivation. Values represent composite soil samples collected from each treatment at the end of the experiment.
ParametersBiostimulant-Free
Control		MicroelementArbuscular
Mycorrhizal
Fungi		MicroorganismsOzonated
Vegetable
Oil		Humic
Substance
Sand (20–2000 µm)22.029.82837.835.837.8
Silt (2–20 µm)46.538.852.538.838.838.8
Clay (2 µm)31.531.419.523.425.423.4
pH7.97.98.08.08.18.1
CEC (meq/100 g)30.334.433.535.529.628.8
Electrical conductivity (mS cm−1)0.270.190.490.210.180.19
Total nitrogen (g kg−1)1.71.91.52.02.01.9
Phosphorus (mg kg−1)6.79.812.16.68.58.5
Potassium (mg/kg−1)299245361264234239
Na (mg/kg−1)787173726460
Ca (g kg−1)5.56.44.86.55.45.3
Mg (mg kg−1)212200849198165166
Manganese (mg kg−1)27.926.520.63014.820.8
Zinc (mg kg−1)0.380.380.790.390.310.36
Boron (mg kg−1)1.720.941.200.950.850.80
Iron (mg kg−1)5.195.946.035.953.835.26
Copper (mg kg−1)1.711.634.831.961.441.32
Calcium carbonate (g kg−1)124128166178179162
Organic matter content (%)3.23.42.33.33.73.4
C/N ratio10.310.39.19.710.910.4
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MDPI and ACS Style

Losacco, D.; Puglisi, R.; Salvemini, C.; Convertini, S. Effects of Microbial and Non-Microbial Biostimulants on Chickpea Growth, Yield, and Soil Properties in a Marginal Mediterranean Environment. AgriEngineering 2026, 8, 268. https://doi.org/10.3390/agriengineering8070268

AMA Style

Losacco D, Puglisi R, Salvemini C, Convertini S. Effects of Microbial and Non-Microbial Biostimulants on Chickpea Growth, Yield, and Soil Properties in a Marginal Mediterranean Environment. AgriEngineering. 2026; 8(7):268. https://doi.org/10.3390/agriengineering8070268

Chicago/Turabian Style

Losacco, Daniela, Roberto Puglisi, Carlo Salvemini, and Stefano Convertini. 2026. "Effects of Microbial and Non-Microbial Biostimulants on Chickpea Growth, Yield, and Soil Properties in a Marginal Mediterranean Environment" AgriEngineering 8, no. 7: 268. https://doi.org/10.3390/agriengineering8070268

APA Style

Losacco, D., Puglisi, R., Salvemini, C., & Convertini, S. (2026). Effects of Microbial and Non-Microbial Biostimulants on Chickpea Growth, Yield, and Soil Properties in a Marginal Mediterranean Environment. AgriEngineering, 8(7), 268. https://doi.org/10.3390/agriengineering8070268

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