Field evaluation of bone biochar for improving maize yield, soil health, and carbon efficiency in arid soils

Abstract

Background

the study aims to evaluate the effectiveness of bone-derived biochar, produced from slaughterhouse waste, as a multifunctional soil amendment within a climate-smart and circular agriculture framework. The central research question explores whether biochar can enhance maize (Zea mays) productivity, improve soil health, and reduce greenhouse gas (GHG) emissions in arid agroecosystems. A two-season field experiment was conducted on loamy sand soil under drip irrigation to assess the impact of biochar applied at 0, 5, 10, and 20 t ha⁻¹. The responses measured included agronomic traits (plant height, biomass, grain yield), soil biochemical properties (organic carbon, available phosphorus, microbial biomass carbon), GHG emissions (CO₂ and N₂O), and economic returns. Principal Component Analysis (PCA) was applied to integrate the agronomic, environmental, and economic outcomes.

Results

biochar significantly improved plant growth, increased biomass by 28%, grain yield by 51%, and enhanced soil quality indicators. Notably, it reduced CO₂ emissions by 24% and N₂O by 15%. The 10 t ha⁻¹ application rate was identified as the most effective in balancing yield, soil health, and emissions mitigation.

Conclusions

bone-derived biochar offers a sustainable, climate-resilient strategy for improving maize productivity and soil health while contributing to GHG reduction and supporting circular economy goals in arid farming systems.

Background

Sustainable agricultural intensification has become a global imperative under the dual challenges of climate change and resource depletion. Modern agroecosystems are pressured to increase productivity while maintaining environmental integrity, particularly in arid and semi-arid regions such as Egypt, where soil fertility constraints and water scarcity limit crop performance [8, 10, 21]. The transition toward circular bio-economy principles valorizing organic residues into value-added inputs represents a viable pathway toward resilient and low-emission food systems [16].

Biochar, a carbon-rich product obtained from the pyrolysis of organic biomass under limited oxygen, has received growing attention as a soil amendment with multifunctional benefits. Numerous studies have demonstrated its capacity to enhance soil physical and chemical properties, including cation exchange capacity, water retention, and nutrient availability [6, 8, 14, 28]. The porous structure and high surface area of biochar also improve microbial habitat conditions, thus stimulating soil biological activity and microbial biomass carbon critical drivers of soil organic matter dynamics and nutrient cycling [7].

From a climate mitigation perspective, biochar has been recognized as an effective carbon sequestration agent and as a tool to reduce greenhouse gas (GHG) emissions, particularly CO₂ and N₂O, by altering soil redox and microbial processes [13, 26]. Integration of biochar with fertilizer management further enhances nitrogen-use efficiency and lowers nitrous oxide fluxes from fertilized soils [5]. Such synergistic effects underline the potential of biochar-based systems within climate-smart agriculture frameworks.

In the Egyptian context, where annual production of agricultural residues exceeds 30–35 million tons, improper disposal (e.g., open burning) contributes significantly to air pollution and GHG emissions [8]. Transforming these residues into biochar supports waste valorization, improves soil fertility in degraded lands, and aligns with the Egypt Vision 2030 strategy promoting sustainable resource use (Ministry of Environment, 2023). Locally produced biochar from animal bones and crop residues is gaining research and commercial attention due to its high nutrient content (Ca, P) and stability under sandy soil conditions [4, 15].

Field-level evidence has shown that applying biochar at rates between 5–20 t ha⁻¹ in combination with balanced NPK fertilization improves grain yield, plant growth, and physiological traits such as chlorophyll content and leaf area index, while also reducing carbon losses and improving soil organic carbon over time [9, 12, 25, 27]. Moreover, recent economic assessments highlight the positive cost–benefit ratio of biochar use, emphasizing its long-term profitability despite higher initial costs [9, 18].

While numerous studies have examined the effects of biochar on crop productivity and soil quality, field-based evidence on the performance of bone-derived biochar produced from slaughterhouse waste under arid conditions remains scarce. Furthermore, few studies have integrated agronomic, soil health, greenhouse gas emission, and economic assessments within a single evaluation framework. Therefore, the novelty of the present study lies in its comprehensive assessment of bone-derived biochar as a multifunctional soil amendment within a climate-smart and circular agriculture framework, with a particular focus on identifying the most favorable application rate for enhancing maize productivity, improving soil quality, and promoting environmental sustainability in low-fertility sandy soils.

Methods

Experimental site and conditions

Field experiments were conducted during the summer seasons of 2024 and 2025 at the Giza, Egypt (30.027797° N, 31.189588° E), under semi-arid climatic conditions. The site is characterized by loamy sand soil, as classified according to the USDA soil textural classification system using the soil texture triangle, with a particle size distribution of approximately 82% sand, 12% silt, and 6% clay. The experiment was conducted under a drip irrigation system.

Baseline soil characteristics were assessed prior to sowing (Table 1), indicating a slightly alkaline pH (7.8), low organic matter content (0.62%), and moderate cation exchange capacity (9.4 cmol kg⁻¹).

Table 1.

Physical and chemical properties of experimental site before sowing (0–15 cm depth)

Soil property	Value
Sand (%)	82
Silt (%)	12
Clay (%)	6
Soil Texture	Loamy Sand
Bulk Density (g/cm3)	1.55
Field Capacity (%)	13.5
Permanent Wilting Point (%)	6.8
Saturated Hydraulic Conductivity (cm/hr)	9.4
pH (1:2.5 soil:water)	7.8
Electrical Conductivity (dS/m)	1.2
Organic Matter (OM,%)	0.62
Total Nitrogen (%)	0.08
Available Phosphorus (mg/kg)	7.5
Available Potassium (mg/kg)	145
Cation Exchange Capacity (cmol(+)/kg)	9.4
Calcium Carbonate (%)	1.4
Exchangeable Sodium (%)	0.45

Experimental design and treatments

A randomized complete block design (RCBD) with three replicates was used to assess the effect of biochar derived from bone waste on maize growth and soil properties. The plot size was 4 m × 3 m, with 75 cm row spacing and 25 cm plant spacing.

The study consisted of four treatments: Control (T0)—recommended NPK dose without biochar, Low Biochar Dose (T1)—5 t ha⁻¹, Medium Biochar Dose (T2)—10 t ha⁻¹, and High Biochar Dose (T3)—20 t ha⁻¹.

All treatments, except T0, received biochar prior to sowing. The recommended fertilizer rate (120 kg N, 60 kg P₂O₅, and 60 kg K₂O per hectare) was applied uniformly to all plots. Nitrogen in form of Nitrate (33.5% N) was applied in two split doses 30 and 50 days after emergence, phosphorus in form of triple superphosphate (46% P₂O₅) applied at planting, and potassium applied in form of potassium sulfate (50% K₂O), with the first dose of nitrogen fertilizer.

Biochar production and characterization

Biochar was produced from slaughterhouse bone waste collected from municipal abattoirs in Giza. The material was air-dried, crushed, and pyrolyzed at 500 °C for 3 h in a controlled oxygen-limited environment using a batch pyrolysis reactor. The resulting biochar was sieved (< 2 mm) and characterized for key physico-chemical properties: pH (9.4), total C (63.2%), P content (8.1%), and ash content (22.7%) (Table 2).

Table 2.

Physicochemical characteristics of bone-derived biochar used in the field experiment

Biochar property	Value
Feedstock source	Slaughterhouse bone waste
Pyrolysis temperature (°C)	500
pH	9.4
Total carbon (%)	63.2
Total nitrogen (%)	1.5
Available phosphorus (%)	8.1
Ash content (%)	22.7
C:N Ratio	42.1
Surface area (m2/g)	132
Porosity (%)	71
Electrical conductivity (dS/m)	1.9

Elemental composition was analyzed using CHNS elemental analyzer and ICP-OES for macro- and micronutrients. Surface morphology and porosity were assessed via Scanning Electron Microscopy (SEM) and BET surface area analysis.

Crop establishment and management

The maize seeds (Zea mays L., cv. Single Cross 10) used in this experiment were obtained from the Maize Research Department, Agricultural Research Center (ARC), Giza, Egypt an officially certified and nationally accredited source for high-quality hybrid maize germplasm. Maize was sown manually in mid-May of each season. Biochar was incorporated into the top 15 cm of soil two weeks prior to planting using a rotary tiller. Drip lines with in-line emitters (4 L h⁻¹ spacing at 30 cm) delivered irrigation water based on crop evapotranspiration estimates calculated using the FAO Penman–Monteith method.

Weed control, pest management, and cultural practices were uniformly applied across all plots following regional agronomic recommendations.

Data collection and measurements

Soil samples were collected from the 0–15 cm layer both before planting and after harvest during the 2024 and 2025 summer seasons. Composite samples were air-dried, sieved (2 mm), and analyzed for the following parameters:

• • Soil pH and Electrical Conductivity (EC) were measured in a 1:2.5 soil-to-water suspension using a calibrated pH meter and conductivity meter.

• • Organic Carbon (OC) was determined using the Walkley–Black wet oxidation method, and organic matter (OM) was calculated as:

  

• • Available Phosphorus (P) was extracted using the Olsen method and quantified colorimetrically using a spectrophotometer.

• • Total Nitrogen (N) was determined by the Kjeldahl digestion method.

• • Microbial Biomass Carbon (MBC) was assessed using the chloroform fumigation-extraction technique, where:

  

• Where; (KC = 0.45, EC = difference between fumigated and unfumigated C).

Plant growth and physiological parameters

Growth and physiological attributes were recorded at tasseling and harvest stages:

• Leaf Area Index (LAI): calculated as

• Chlorophyll Content (SPAD): recorded using a SPAD-502 Plus chlorophyll meter from the uppermost fully expanded leaf.

• Aboveground Biomass (t ⁻¹): determined by oven-drying samples at 70 °C until constant weight, expressed on a per-hectare basis.

Yield and yield components

At harvest, the following yield parameters were measured:

• • Grain Yield (t ha⁻¹): adjusted to 15% moisture content.

• • 1000-Kernel Weight (g): determined by weighing 1000 randomly selected grains per plot.

Greenhouse gas emissions

During the 2024 and 2025 growing seasons, CO₂ and N₂O emissions were monitored biweekly using a closed static chamber method. Gas samples were collected between 9:00 and 11:00 a.m. and analyzed using gas chromatography (GC) equipped with a flame ionization detector (FID) for CO₂ and an electron capture detector (ECD) for N₂O. Fluxes were calculated using the equation:

where F = flux (mg m⁻² h⁻¹), ΔC/Δt = rate of change in gas concentration, V = chamber volume, A = chamber area, M = molar mass of gas, and T = air temperature (°C).

Economic analysis

Economic evaluation was conducted for each treatment:

• Gross Revenue (USD ha-¹) = Grain Yield (t ha⁻¹) × Market Price (USD t⁻¹).

• Total Cost (USD ha-¹): includes costs of biochar, fertilizers, irrigation, and labor.

• Net Profit (USD ha-¹) = Gross Revenue - Total Cost.

• Benefit–Cost Ratio (BCR) = Gross Revenue / Total Cost.

Statistical analysis

Data from each growing season were analyzed using one-way analysis of variance (ANOVA) to evaluate the effects of biochar application rates. When significant differences (p ≤ 0.05) were observed, least significant differences (L.S.D) test was used for mean separation. Statistical computations were performed using R software (v4.2.3). Pearson correlation and Principal Component Analysis (PCA) were conducted to examine relationships among measured variables.

Results

Plant growth and physiological responses

Biochar significantly enhanced the vegetative performance of Zea mays during both the 2024 and 2025 growing seasons. Leaf area index (LAI) increased progressively with higher biochar rates, with the 20 tha⁻¹ treatment exhibiting the highest values (Fig. 1).

Fig. 1.

Effect of biochar rates on maize growth parameter, leaf area index, during the 2024 and 2025 seasons. Values represent means ± standard error (SE). different letters on bars indicate significant differences among treatments according to the LSD test at p ≤ 0.05

Chlorophyll content, measured via SPAD values, followed a similar trend, indicating enhanced photosynthetic efficiency and nitrogen assimilation (Fig. 2).

Fig. 2.

Variation in physiological response (chlorophyll content – SPAD) of maize plants under different biochar treatments. Values represent means ± standard error (SE). different letters on bars indicate significant differences among treatments according to the LSD test at p ≤ 0.05

The improvement in aboveground biomass production and dry matter accumulation in biochar-treated plots further emphasizes its agronomic value. The 10–20 t ha⁻¹ treatments produced up to 28% more biomass than control plots (Fig. 3).

Fig. 3.

Variation in physiological response (aboveground biomass) of maize plants under different biochar treatments. Values represent means ± standard error (SE). different letters on bars indicate significant differences among treatments according to the LSD test at p ≤ 0.05

Yield and its components

Yield attributes showed significant responses to biochar applications (Table 3). Grain yield increased by an average of 42–51% relative to the control, while the 1000-kernel weight improved by approximately 12%. Such responses confirm the role of biochar in improving nutrient synchronization with crop demand, thereby enhancing assimilate partitioning to reproductive organs.

Table 3.

Effects of bone-derived biochar rates on maize grain yield and 1000-kernel weight during the 2024 and 2025 seasons

Treatment	Grain yield (t ha−1) Mean ± SE		1000-kernel weight (g) Mean ± SE
	2024	2025	2024	2025
T0—Control	3.10 ± 0.04 cd	3.15 ± 0.03 d	260 ± 4.20 d	263 ± 3.91 d
T1—5 t ha−1	3.41 ± 0.06 bc	3.57 ± 0.07 bc	272 ± 3.62 bc	276 ± 4.31 bc
T2—10 t ha−1	3.80 ± 0.05 b	3.83 ± 0.06 b	281 ± 3.80 ab	284 ± 4.81 ab
T3—20 t ha−1	4.39 ± 0.07 a	4.66 ± 0.08 a	290 ± 5.24 a	293 ± 4.61 a

* Different letters among column indicate significant differences among treatments according to the LSD test at p ≤ 0.05

The stability of these improvements across both seasons underscores biochar’s cumulative soil conditioning effect. The significant (p < 0.05) differences among treatments as revealed by the L.S.D test affirm the consistency of biochar’s performance under variable climatic conditions.

Soil fertility, microbial activity, and carbon dynamics

Post-harvest soil assessments revealed substantial improvements in key soil health indicators (Table 4). Soil organic carbon (SOC) increased by approximately 30%, available phosphorus by 50%, and microbial biomass carbon (MBC) by 45%, especially under the 10 and 20 t ha⁻¹ treatments.

Table 4.

Influence of bone-derived biochar on soil organic carbon, available phosphorus, and microbial biomass carbon at harvest during the 2024 and 2025 seasons

Treatment	Soil Organic Carbon (SOC, %) Mean ± SE		Available Phosphorus (mg/kg) Mean ± SE		Microbial Biomass C (mg/kg) Mean ± SE
	2024	2025	2024	2025	2024	2025
T0—Control	0.46 ± 0.02 c	0.45 ± 0.08 c	147.50 ± 15.00 d	149.00 ± 14.00 d	10.30 ± 1.20 bcd	7.50 ± 1.10 cd
T1—5 t ha−1	0.49 ± 0.13 b	0.51 ± 0.02b	156.00 ± 18.00 c	161.00 ± 17.00 c	11.30 ± 1.30 bc	11.40 ± 1.40 c
T2—10 t ha−1	0.53 ± 0.01 a	0.56 ± 0.06 a	185.50 ± 22.00 b	190.30 ± 21.00 b	13.90 ± 1.50 b	17.50 ± 1.60 ab
T3—20 t ha−1	0.58 ± 0.04 a	0.60 ± 0.02 a	212.50 ± 25.00 a	218.70 ± 24.00 a	20.60 ± 1.80 a	21.50 ± 2.00 a

Greenhouse Gas Emissions (GHG)

A substantial reduction in soil CO₂ and N₂O fluxes was observed with biochar treatments (Table 5). The 20 t ha⁻¹ treatment reduced CO₂ emissions by 24% and N₂O emissions by 15% compared to the control. The mitigative effect is primarily attributed to biochar’s ability to alter redox potential, retain nitrogen in ammonium form, and reduce denitrification losses.

Table 5.

Seasonal CO₂ and N₂O emissions as affected by bone-derived biochar application rates during the 2024 and 2025 cropping seasons

Treatment	CO₂ Emission (mg C/m2/day) Mean ± SE		N₂O Emission (µg N/m2/day) Mean ± SE
	2024	2025	2024	2025
T0—Control	82.90 ± 3.50 a	72.70 ± 2.80 ab	255.10 ± 13.00 a	243.10 ± 12.00 a
T1—5 t ha−1	63.40 ± 3.10 bc	77.20 ± 3.60 a	231.60 ± 15.00 ab	219.20 ± 14.00 b
T2—10 t ha−1	69.30 ± 2.90 b	63.50 ± 3.00 cd	217.30 ± 14.00 bcd	214.30 ± 13.00 bc
T3—20 t ha−1	63.00 ± 3.30 bc	67.80 ± 3.50 bc	223.30 ± 16.00 bc	219.00 ± 15.00 b

Economic evaluation

Gross revenue peaked at 4685.8 USD ha⁻¹ with 20 t ha⁻¹ biochar. However, due to high production costs, net profit margins were negative in the short term, ranging between −107 and −434 USD ha⁻¹ (Fig. 4). Nevertheless, projections over multiple growing seasons indicated a shift toward positive profitability.

Fig. 4.

Economic performance (gross revenue, production cost, and net profit) of maize under different biochar application rates across the two seasons. Values represent means ± standard error (SE). different letters on bars indicate significant differences among treatments according to the LSD test at p ≤ 0.05

Principal Component Analysis (PCA) and integrated trait assessment

PCA analysis integrating soil, physiological, and economic traits revealed that the first two components explained 74.3% of the total variance (Fig. 5). The first component (PC1) was strongly associated with soil carbon, microbial biomass, and plant height, while PC2 captured yield and revenue responses. Treatments T2 (10 t ha⁻¹) and T3 (20 t ha⁻¹) clustered closely, suggesting that beyond 10 t ha⁻¹, yield and soil benefits plateau.

Fig. 5.

Principal component analysis (PCA) illustrating relationships among biochar rates, soil fertility indicators, and maize yield components

Synthesis

Overall, the findings confirm that bone-derived biochar significantly improves plant growth, soil fertility, and resource efficiency while mitigating GHG emissions. The integration of biochar with standard NPK regimes promotes resilient, climate-smart cropping systems suitable for Egyptian agroecosystems.

Discussion

The observed increases in LAI and SPAD readings reflect improved physiological function in maize under biochar treatment, which improves soil water retention, nutrient availability, and crop productivity under water-limited conditions [5, 6, 25]. The results align with the findings of Sakin et al. [24] and Liu et al. [14], who reported that biochar improves nutrient retention, soil biological activity, and carbon sequestration through its porous structure and high surface area.

The observed increase in biomass production supports previous findings that biochar enhances nutrient availability, root development, and plant growth, particularly in low-fertility soils [9, 24, 25]. Similarly, the significant increases in grain yield and kernel weight are consistent with previous studies demonstrating that biochar enhances nutrient availability, soil biological activity, and nutrient-use efficiency, thereby improving maize productivity [2, 20]. The consistency of these responses across growing seasons further supports the effectiveness of biochar under arid and variable environmental conditions, as reported in other long-term field studies on maize production systems [17]. The observed increases in soil organic carbon and microbial biomass are consistent with findings reported by Sakin et al. [24], who reported that biochar application increased soil enzyme activity, enhanced carbon sequestration, and improved soil biological functioning in calcareous soils. Similarly, Sakin et al. [23] demonstrated that biochar amendments can reduce carbon losses while stimulating beneficial soil biochemical processes. Similar responses have also been reported by Ding et al. [7] highlighting the role of biochar in improving soil carbon dynamics and microbial functioning. This is further validated by Lal [11] (), who advocates biochar as a viable soil carbon sequestration agent. Egyptian studies by Abuzaid et al. [3] and Abdel-Salam et al. [1] confirm that in sandy soils, biochar minimizes leaching losses and enhances nutrient availability, aligning with our findings. Although the bone-derived biochar used in this study was alkaline in nature (pH 9.4), the resulting increase in soil pH was relatively limited and remained within the acceptable range for maize cultivation. Previous studies have shown that maize can tolerate moderately alkaline soils without significant reductions in growth or productivity, particularly when soil fertility and physical properties are improved. In the present study, biochar application enhanced soil organic carbon, available phosphorus, and microbial biomass carbon, while also improving nutrient retention and overall soil quality. These positive effects likely outweighed any potential adverse impacts associated with the slight increase in soil alkalinity. Moreover, the inherently high phosphorus content of bone-derived biochar may have enhanced phosphorus availability, thereby supporting plant growth and grain production despite the alkaline soil conditions.

Although biochar application significantly increased soil organic carbon (SOC) compared with the initial soil condition, the overall SOC levels remained relatively low. This can be attributed to the coarse-textured nature of the experimental soil, which contained a high proportion of sand and a low clay content, thereby limiting its capacity for long-term carbon stabilization and protection within soil aggregates. In addition, the arid environmental conditions and elevated temperatures prevailing at the study site likely accelerated organic matter mineralization and carbon turnover. Therefore, despite the high carbon content of the applied biochar, only a fraction of the added carbon was retained within measurable SOC pools during the two-year experimental period, while the remainder may have undergone transformation into more stable or less readily detectable carbon fractions.

The beneficial effects observed in the present study can be partly attributed to the distinctive chemical characteristics of bone-derived biochar. Unlike most plant-derived biochar, bone biochar is inherently rich in phosphorus and calcium, two essential elements that play key roles in soil fertility and plant development. The elevated phosphorus content likely enhanced phosphorus availability in the nutrient-deficient sandy soil, thereby promoting root development, photosynthetic efficiency, and grain production. Meanwhile, calcium may have improved soil aggregation, nutrient retention, and microbial habitat quality, contributing to enhanced soil functionality. Combined with the high porosity and large surface area of biochar, these properties likely increased nutrient-use efficiency and supported the observed improvements in soil health, plant growth, and crop productivity.

The significant reductions in CO₂ and N₂O emissions reinforce biochar’s value in climate-smart agriculture. These findings agree with Sakin et al. [23] and Sakin et al. [24], who reported that biochar amendments reduced CO₂ emissions and promoted carbon stabilization by modifying microbial activity and improving soil carbon retention. The relationship between soil organic carbon (SOC) content and CO₂ emissions was not strictly linear in the present study. Although SOC levels in T0 and T1 were relatively similar, CO₂ emissions may vary due to differences in carbon turnover processes, including microbial decomposition of native soil organic matter, root respiration, and the turnover of labile carbon compounds. Biochar application can reduce CO₂ emissions by enhancing carbon stabilization, promoting aggregate formation, protecting organic matter from microbial decomposition, and modifying microbial activity. Therefore, the lower CO₂ emissions observed in biochar-amended treatments likely reflect improved carbon retention and reduced mineralization rates rather than differences in total SOC content alone. Although short-term economic returns were limited by the relatively high costs associated with biochar production and application, the observed improvements in crop productivity, soil health, and greenhouse gas mitigation suggest the potential for additional economic benefits over time. However, the extent to which these benefits may translate into long-term profitability requires further investigation through dedicated long-term economic assessments. Studies by Mekky et al. [18] advocate for localized biochar production using agricultural residues, which can offset up to 40% of initial costs. Furthermore, inclusion in carbon credit systems may enhance its financial attractiveness. Although the short-term economic benefits of biochar application were limited by the relatively high costs associated with its production and field application, the significant improvements observed in crop productivity, soil health parameters, and greenhouse gas mitigation underscore its broader contribution to sustainable agricultural systems. Biochar is widely recognized as a long-term soil amendment, with benefits that accumulate over time through progressive improvements in soil structure, nutrient retention, carbon sequestration, and resource-use efficiency. Therefore, assessments based solely on short-term profitability may not fully capture the long-term agronomic, environmental, and ecological advantages of biochar application, particularly in degraded sandy soils under arid and semi-arid conditions.

The PCA results indicated that the 10 t ha⁻¹ biochar treatment was associated with the most favorable combination of agronomic performance, soil health indicators, environmental benefits, and economic returns. Although PCA is an exploratory tool and cannot be used to define an optimal application rate, the multivariate analysis suggests that this treatment achieved a more balanced overall response than the other biochar application rates evaluated under the conditions of the present study.. Similar trends have been reported in previous biochar studies, where moderate application rates often provide the best balance between crop productivity, soil improvement, and economic feasibility, while higher rates yield diminishing marginal benefits [5, 25].The bone-derived biochar significantly improves plant performance, soil health, and environmental sustainability in arid Egyptian soils. These outcomes are consistent with regional and global literature emphasizing the transformative role of biochar in achieving circular economy goals and enhancing the resilience of agroecosystems [3, 22] .

A key contribution of this study is demonstrating that bone-derived biochar produced from slaughterhouse waste can simultaneously enhance maize productivity, improve soil health indicators, and reduce greenhouse gas emissions under arid conditions. By integrating agronomic, environmental, and economic evaluations and employing PCA to show the most favorable overall performance or emerged as the most balanced treatment, the study provides a comprehensive assessment of biochar performance and offers practical insights for the sustainable management of low-fertility sandy soils within a climate-smart and circular agriculture framework.

Limitations of the study

Notwithstanding the encouraging outcomes, a few issues need to be noted. Initially, the research was carried out at a single site during two growing seasons, which might restrict the findings' applicability to other soil types and climates. Second, although the biochar had favorable short-term effects, it is unclear how it will affect soil carbon stability, nutrient dynamics, and economic viability in the long run. Third, only one season's worth of GHG emissions were tracked, which might have missed interannual variability. To learn more about the scalability and environmental trade-offs of bone biochar in various agroecosystems, future multi-location and multi-year trials as well as life-cycle assessments are required.

Author’ contributions

Conceptualization, L.M and E.E.; Methodology, E.M.; Validation, L.M and E.E.; Formal Analysis, L.M.; Investigation, E.E.; Resources, L.M.; Data Curation, E.E.; Writing – Original Draft Preparation, E.E.; Writing – Review & Editing, L.M.; Visualization, E.E.; Supervision, L.M.; Project Administration, L.M.; Funding Acquisition, L.M.

Funding

This work was supported by the Deanship of Scientific Research, Vice Presidency for Graduate Studies and Scientific Research, King Faisal University, Saudi Arabia (KFU263406).

Data availability

All data generated or analysed during this study are included in this published article.

Declarations

Ethics approval and consent to participate

Not applicable.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.