Functionalized biochar from waste as a slow-release nutrient source: Application on tomato plants.

Area of Science:

• Agricultural Science
• Environmental Science
• Materials Science

Background:

• Valorization of agricultural waste (licorice processing residue) into biochar.
• Potential of biochar as a slow-release fertilizer to improve soil properties and plant nutrition.

Purpose of the Study:

• To produce and characterize biochar from licorice waste for slow-release fertilizer applications.
• To evaluate the nutrient release kinetics and performance of biochar on tomato (Solanum lycopersicum) growth.

Main Methods:

• Pyrolysis of licorice waste at 500°C and 700°C to produce biochar (BC500, BC700).
• Characterization using BET, SEM, elemental analysis, and point of zero charge (pHzc).
• Functionalization with NPK, desorption tests at different pH, and greenhouse trials with varying biochar dosages and NPK ratios.

Main Results:

• BC500 exhibited slower nutrient release kinetics (14 days equilibrium) compared to BC700 (10 days), attributed to smaller pore size.
• Functionalized BC500 showed higher NPK content and lower desorption rates (Kdes).
• Optimal treatment (25% BC500, NPK ratio 4:1:3) significantly increased total chlorophyll (+38%) and carotenoids (+15%) in tomato plants.

Conclusions:

• Licorice-derived biochar, particularly BC500, is a promising material for slow-release fertilizers.
• Biochar application can enhance crop yield and quality by improving nutrient availability and plant physiology.
• Utilizing agricultural waste for biochar production offers a sustainable approach to waste management and soil amendment.