Biochar Interactive Effects with
Potting Mixture & Biostimulant
on Soil Properties and Bean
Growth
Marc-Ari Weekes, Jeff Chandler and Francis Lopez
Department Of Biological & Chemical Sciences
The University Of The West Indies, Cave Hill, Barbados
Effects of Biochar on Soil
Increases Surface Area and
Porosity:
Water Retention
Soil Aeration
Nutrient Retention
Liming Effect
Rhizobial Activity
Verheijen, et al. (2010)
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Objectives
Investigate interactions between biochar, potting media texture and biostimulant application in a legume crop
Test Crop: Bean (Phaseolus vulgaris, ‘Green Crop’)
Biochar prepared from Leucaena leucocephala wood feedstock using low-tech drum technology
Hypotheses:
Biochar will be more beneficial in sandy soils due to effects on water and nutrient retention
Biochar + Biostimulant will have synergistic effects on plant growth
Biochar will have beneficial effects on nodulation and nitrogen fixation
Methods
Potted bean plants in 4L pots
Independent Variables: Sand/clay soil Ratio (25%, 50%, 75% sand)
Biochar (Absent/Present) - Leucaena leucocephala biochar (<2mm) – 10% v/v
Biostimulant (Absent/Present) - EM1, Bio-Logic Manufacturing, Barbados - 50 mL/L weekly application
Randomized Block Design – 4 Reps Low fertilizer level applied weekly to all
pots (0.35 g/L, 24:8:16, Scotts Miracle-Gro)
Biochar and soil texture (sand %)
interaction on Soil Moisture
Pod dry mass yield
1
2
3
4
20 40 60 80
Pod y
ield
g/pla
nt
Soil texture (% sand)
b b
a
0
1
2
3
Absent Present
Pod y
ield
g/pla
nt
Biochar
a a
Effect of Biochar and soil texture
(sand %) on Harvest Index
Pod yield was not significantly affected by biochar
Effect of Biochar and Sand %
interaction on Nodulation
Chi-square test of association, p < 0.01
Effect of Biochar and Biostimulant
interaction on Nodulation
Chi-square test of association, p < 0.01
Conclusion
Pod yield was not significantly affected by biochar with or without biostimulant
Biochar can ameliorate negative effects of sandy soil on soil moisture
Positive effects of biochar observed on the number of root nodules
but nodules appeared to be non-effective
Biostimulant increased the number of root nodules in absence of biochar