Report on the Efficacy of Nano-Micronutrient Fertilizers for Sustainable Maize Production in Calcareous Soils

Introduction: Aligning Agricultural Innovation with Sustainable Development Goals (SDGs)

Global food security, a cornerstone of SDG 2 (Zero Hunger), faces significant challenges from soil degradation and the environmental impact of conventional agriculture. In Egypt, maize cultivation in calcareous soils is hampered by low nutrient availability, threatening local food supplies. Traditional chemical fertilizers, while boosting yields, contribute to environmental pollution and are economically burdensome, conflicting with SDG 12 (Responsible Consumption and Production) and SDG 15 (Life on Land). This report details a study investigating nano-fertilizers (NFs) as a sustainable alternative. NFs offer a technologically advanced method to enhance nutrient use efficiency, improve crop productivity, and reduce the ecological footprint of farming, thereby promoting sustainable agricultural practices.

Methodology: A Field-Based Investigation

A field experiment was conducted during the 2022 and 2023 summer seasons at the El-Nubaria Research Station, Egypt, to assess the impact of NFs on maize productivity in calcareous soil.

Experimental Design

• Study Design: A randomized complete block design (RCBD) with three replications.
• Treatments: The study compared the effects of various foliar spray treatments:
  1. Control (no treatment)
  2. Nano-Zn (20 mg/L and 40 mg/L)
  3. Nano-Mn (20 mg/L and 40 mg/L)
  4. Nano-Mo (20 mg/L and 40 mg/L)
  5. Traditional Zn-chelate (2 g/L)
  6. Traditional Mn-chelate (2 g/L)
  7. Traditional Ammonium Molybdate (250 mg/L)
• Analysis: Synthesized nanoparticles (ZnO-NPs, MnO₂-NPs, MoO₃-NPs) were characterized using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Data on vegetative growth, yield components, and nutrient content in leaves, grains, and soil were collected and statistically analyzed.

Key Findings: Advancing Food Security and Sustainable Production

The application of nano-fertilizers, particularly at a concentration of 40 mg/L, demonstrated superior performance over both the control and traditional fertilizers, contributing directly to several SDGs.

Impact on Crop Yield and Productivity (SDG 2: Zero Hunger)

• Enhanced Grain Yield: The highest grain yield was achieved with 40 mg/L of Nano-Mn, producing 15.1 tons/ha, a substantial increase from the control group’s 9.84 tons/ha. This directly addresses the goal of increasing food production.
• Improved Yield Components:
  • The highest grain weight per plant (239.4 g) was recorded with 40 mg/L of Nano-Mo.
  • The highest 100-grain weight (40.7 g) was obtained with 40 mg/L of Nano-Zn.
• Vegetative Growth: All NF treatments significantly improved plant height and fresh weight, with Nano-Mo at 40 mg/L leading to the highest fresh weight per plant (1.377 kg).

Nutrient Biofortification and Soil Health (SDG 12 & SDG 15)

NFs improved the nutritional quality of the maize and enhanced nutrient availability in the soil, promoting more responsible production cycles and contributing to the health of terrestrial ecosystems.

Nutrient Content in Maize Leaves and Grains

• Enhanced Nutrient Uptake: Plants treated with 40 mg/L of Nano-Zn showed the highest leaf concentrations of Phosphorus (0.98%), Potassium (1.0%), Iron (268 mg/kg), Zinc (79 mg/kg), and Copper (24.3 mg/kg).
• Nitrogen and Protein Content: The application of 40 mg/L of Nano-Mo resulted in the highest leaf Nitrogen (3.96%) and the highest grain protein content (10.25%), improving the nutritional value of the crop.
• Manganese Content: The highest leaf Manganese concentration (271.7 mg/kg) was achieved with 40 mg/L of Nano-Mn.

Impact on Soil Nutrient Availability

• The foliar application of NFs led to an increase in available macro- and micro-nutrients in the soil post-harvest.
• Nano-Mo (40 mg/L) treatment resulted in the highest available Phosphorus (16.2 mg/kg) and Potassium (289.5 mg/kg) in the soil.
• Treatments with a specific nano-nutrient (Zn, Mn, Mo) correspondingly increased the available amount of that nutrient in the soil, indicating a positive feedback loop for soil fertility and reducing the need for excessive fertilizer application in subsequent seasons.

Discussion and Conclusion: A Pathway to Sustainable Agriculture

The results confirm that nano-micronutrient fertilizers are a highly effective technology for enhancing maize productivity in challenging calcareous soil conditions. By increasing nutrient use efficiency, NFs allow for lower application doses compared to traditional fertilizers, which directly supports SDG 12 (Responsible Consumption and Production) by minimizing resource waste and chemical inputs.

The significant boost in yield and the biofortification of grains with essential nutrients are critical advancements for SDG 2 (Zero Hunger), enhancing both food quantity and quality. Furthermore, the improved soil health and reduced potential for chemical runoff associated with NFs contribute positively to SDG 15 (Life on Land).

In conclusion, the adoption of nano-fertilizers presents a viable, cost-effective, and environmentally responsible strategy. It is recommended that NFs be considered a key tool for developing sustainable agricultural systems that can meet the demands of a growing population while protecting planetary health, in line with the United Nations’ Sustainable Development Goals.

Analysis of Sustainable Development Goals in the Article

1. Which SDGs are addressed or connected to the issues highlighted in the article?

1. SDG 2: Zero Hunger

   The article directly addresses SDG 2 by focusing on enhancing food production. The core of the research is to “maximize maize productivity” and increase “crop yield and quality.” Maize is a staple food source used for “human food, animal feed, and industrial purposes,” and improving its yield contributes directly to food security.

2. SDG 9: Industry, Innovation, and Infrastructure

   The study is centered on applying an “innovative technology” – nanotechnology – to agriculture. It investigates the use of nano-fertilizers (NFs) as a modern solution to traditional farming challenges. This aligns with the goal of promoting scientific research and upgrading technological capabilities to foster sustainable development.

3. SDG 12: Responsible Consumption and Production

   The article highlights the problems with “synthetic chemical fertilizers,” which can be “costly for farmers and harmful to the environment.” It proposes nano-fertilizers as a solution that offers “higher nutrient use efficiency” and is an “eco-friendly alternative.” This promotes the sustainable management and efficient use of natural resources and reduces the release of harmful chemicals into the environment.

4. SDG 15: Life on Land

   The research is conducted in “calcareous soil,” a type of challenging or degraded land with “low organic matter, and poor availability of nutrients.” By demonstrating that nano-fertilizers can improve “soil quality,” “nutrient availability,” and “overall soil health,” the article connects to the goal of restoring degraded land and soil.

2. What specific targets under those SDGs can be identified based on the article’s content?

• Target 2.4: Sustainable food production and resilient agricultural practices

  This target aims to ensure sustainable food production systems and implement practices that increase productivity, help maintain ecosystems, and progressively improve land and soil quality. The article’s focus on using “sustainable nano-fertilizers” to increase “maize productivity” while being an “eco-friendly alternative” that improves “soil quality” directly supports this target.

• Target 9.5: Enhance scientific research and upgrade technology

  This target encourages enhancing scientific research and upgrading technological capabilities. The article is a clear example of this, as it is a “field experiment” designed to “investigate the application of nano-fertilizers as an innovative technology to maximize maize productivity.”

• Target 12.4: Environmentally sound management of chemicals and wastes

  This target calls for reducing the release of chemicals into the air, water, and soil. The article addresses this by presenting nano-fertilizers as a method to reduce reliance on “synthetic chemical fertilizers,” which are described as potentially “harmful to the environment.” The study emphasizes that NFs provide a “more ecologically friendly way of farming.”

• Target 15.3: Combat desertification, restore degraded land and soil

  This target focuses on restoring degraded land and soil. The study’s setting in “calcareous soil” and its objective to improve nutrient availability and productivity on this challenging soil type directly relate to this target. The research shows that NFs can enhance “micronutrient efficiency in soils” and improve “overall soil health,” contributing to the restoration of degraded agricultural land.

3. Are there any indicators mentioned or implied in the article that can be used to measure progress towards the identified targets?

Yes, the article provides several quantitative indicators that can be used to measure progress:

• Agricultural Productivity Indicators (Target 2.4): The study measures several crop yield components.
  • Maize grain yield (ton/ha): “The treatment 40 mg/L Nano-Mn produced the most grain (15.1 tons/ha) in comparison to the control (9.84 tons/ha).”
  • Weight of 100 grains (g): “The highest 100-grain weight (40.7 g) was obtained with 40 mg/L Nano-Zn.”
  • Grain weight per plant (g): “The Nano-Mo 40 mg/L treatment had a much greater grain weight per plant (239.4 g).”
• Nutrient Quality and Efficiency Indicators (Targets 2.4 & 12.4): The article measures nutrient content in the plant and soil, indicating more efficient uptake and better food quality.
  • Nutrient content in grains: “treating maize grains with Nano-Mo 40 mg/L showed increasing noticeably for both protein (10.25%) and nitrogen contents in grains (1.64%).”
  • Nutrient content in leaves: “The Nano-Zn 40 mg/L treatment shows the highest significance in phosphorus content (0.98%) and potassium content (1.0%).”
• Soil Health Indicators (Target 15.3): The study analyzes the soil after the harvest to measure the impact on soil quality.
  • Available nutrients in soil: “the available phosphorus in calcareous soil showed the highest significance in the treatments Nano-Mo 40 mg/L, Nano-Zn 40 mg/L, and Nano-Mo 20 mg/L with values of 16.2, 15.53, and 15.43 mg/kg, respectively.”
• Innovation and Research Indicators (Target 9.5): The entire experimental setup serves as an indicator of research and innovation.
  • The execution of a “field experiment” using a “randomized completely block design” to test an “innovative technology.”
  • The characterization of nano-materials using advanced techniques like “X-ray diffraction (XRD) and transmission electron microscopy (TEM).”

4. Table of SDGs, Targets, and Indicators

Source: nature.com