نوع مقاله : مقاله پژوهشی
نویسندگان
گروه مهندسی منابع طبیعی، دانشکده کشاورزی منابع طبیعی، دانشگاه هرمزگان، بندرعباس، ایران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Introduction: Iran generates a considerable volume of biowaste daily, stemming from agricultural, industrial, and domestic activities. Improper disposal of these organic residues not only contributes to environmental degradation but also leads to the loss of valuable nutrient-rich materials that could otherwise be repurposed for soil enhancement. In response to growing concerns over soil fertility depletion and the environmental impact of chemical fertilizers, recent approaches in sustainable agriculture have emphasized the utilization of organic waste as bio-amendments. Macronutrients such as nitrogen (N), phosphorus (P), and potassium (K), along with organic carbon, are essential for maintaining soil health, improving crop productivity, and promoting long-term ecological balance.
Material and methods: This study was conducted to explore the potential of locally available biowaste in Minab County, Iran, specifically orchard and marine residues, for the development of innovative bio-amendments. Four types of soil conditioners were synthesized: two nanoscale biochar materials, nanobiochar derived from palm tree stems and nanobiochar from date pits, and two organic composite amendments formed by integrating chitosan with each nanobiochar type. The objective was to assess their effectiveness in enhancing soil macronutrient content and organic carbon levels under controlled greenhouse conditions. A factorial experiment was designed using a completely randomized layout, with three application rates (0%, 1%, and 2% by weight) and three replicates per treatment. The amendments were thoroughly mixed with soil and incubated in pots for a period of 90 days. Following the incubation, soil samples were collected and analyzed for NPK and organic carbon concentrations. Statistical analysis was performed using R software, and treatment comparisons were conducted using Tukey’s post hoc test to determine significant differences.
Results and discussion: The results revealed that all bio-amendments significantly improved soil nutrient status compared to the untreated control. Notably, the chitosan–nanobiochar composite derived from date pits exhibited the highest efficacy in enhancing nitrogen, phosphorus, and potassium levels. In contrast, amendments derived from palm stems—both the nanobiochar and its chitosan composite—were more effective in increasing soil organic carbon, likely due to their higher lignocellulosic content and greater carbon stability. An increase in application rate positively influenced soil nitrogen content across most treatments, particularly in palm stem nanobiochar, date pit nanobiochar, and the palm stem composite. However, phosphorus levels remained statistically unchanged with increasing amendment rates, suggesting limited mobility or bioavailability under the given conditions. Potassium levels showed a significant response only in the date pit composite treatment, indicating a synergistic effect between chitosan and the biochar matrix. Organic carbon content increased significantly in both composite treatments as the application rate rose from 1% to 2%, underscoring the role of chitosan in enhancing carbon retention and microbial activity. These findings demonstrate that the studied bio-amendments possess strong potential to serve as sustainable alternatives to conventional chemical fertilizers. Their ability to enrich soil with essential nutrients and organic matter makes them particularly valuable for restoring degraded soils, especially in arid and semi-arid regions. Furthermore, the use of such amendments contributes to reducing environmental pressure from biowaste accumulation, promoting circular resource use, and supporting long-term agricultural sustainability.
Conclusion: The integration of nanotechnology and biopolymer composites in soil amendment strategies offers a promising pathway toward eco-friendly and cost-effective solutions for soil fertility management. Future research should focus on field-scale validation, long-term soil health monitoring, and optimization of amendment formulations tailored to specific crop and soil types.
کلیدواژهها [English]
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