Figures (1)  Tables (5)

    • Figure 1. 

      Proximate analysis of KCHW-biochar and KCHW-ash.

    • Period Volume of king coconut nut export (MT) Value generated from king coconut nut exportation
      (LKR. millions)
      January to September 2022 8,236,427 1,516.58
      January to September 2023 9,991,401 2,556.24
      Change (%) 21 69

      Table 1. 

      Export performance of king coconut nuts in Sri Lanka[4].

    • Pyrolysis temperature (°C) Total nutrient content (%) Available nutrient content (%)
      N P K Ca Mg N P K Ca Mg
      300 1.99a 0.42 2.41 0.29b 0.37 0.08 0.05 2.37b 0.21 0.03b
      400 1.37b 0.46 3.02 0.35b 0.41 0.08 0.16 2.62ab 0.21 0.08b
      500 0.58c 0.46 3.33 1.16a 0.41 0.08 0.16 2.93a 0.38 0.24a
      p-value 0.000 0.560 0.116 0.000 0.688 0.980 0.478 0.047 0.055 0.017
      CV 47.55 13.92 19.27 71.42 12.55 25.72 132.38 11.58 40.68 96.38
      * In each column, means that do not share a letter differ significantly at p < 0.05.

      Table 2. 

      Macronutrient composition of KCHW-biochar at different pyrolysis temperatures.

    • Pyrolysis
      temperature
      (°C)      		 Total nutrient content
      Na (%) Fe (%) Cu (ppm) Zn (ppm) Pb (ppm) Ni (ppm)
      300 0.69 0.59 20.56 82.47 1.85 14.45
      400 0.98 0.21 17.37 92.33 0.49 14.16
      500 1.04 0.40 19.66 75.24 0.56 16.51
      p-value 0.142 0.078 0.724 0.377 0.154 0.442
      CV 25.83 54.96 23.26 16.92 100.63 15.13

      Table 3. 

      Micronutrient composition of KCHW-biochar at different pyrolysis temperatures.

    • Pyrolysis temperature (°C) Total nutrient content (%) Available nutrient content (%)
      N P K Ca Mg N P K Ca Mg
      400 2.27a 1.58b 11.79b 2.29 1.30b 0.07 0.82b 8.01 1.13b 0.45
      500 1.15b 2.36a 16.16a 3.11 1.78a 0.05 1.35ab 12.40 1.87a 0.41
      600 0.77b 2.47a 15.49ab 2.19 1.71a 0.04 2.27a 10.60 1.46ab 0.15
      p-value 0.000 0.003 0.027 0.229 0.016 0.381 0.042 0.154 0.010 0.150
      CV 49.68 21.20 16.84 27.68 16.30 42.58 53.19 27.15 24.45 62.62
      * In each column, means that do not share a letter differ significantly at p < 0.05.

      Table 4. 

      Macro-nutrient composition of KCHW-ash at different pyrolysis temperatures.

    • Pyrolysis
      temperature
      (°C)      		 Total nutrient content
      Na (%) Fe (%) Cu (ppm) Zn (ppm) Pb (ppm) Ni (ppm)
      400 4.13 0.68 63.34b 197.91b 0.75 10.65b
      500 5.79 0.88 88.31a 333.09a 2.29 17.47ab
      600 5.39 1.57 88.79a 320.32a 1.36 21.74a
      p-value 0.082 0.132 0.024 0.008 0.157 0.048
      CV 19.53 55.58 18.66 25.52 67.27 36.52
      * In each column, means that do not share a letter differ significantly at p < 0.05.

      Table 5. 

      Micronutrient composition of KCHW-ash at different pyrolysis temperatures.