Table 2: Role of biochar in ameliorating drastically disturbed soils [53].

Limiting factorVariableProblemShort-term treatmentLong-term treatmentRole of biochar

PhysicalSoil structureSoil too compactRip or scarifyVegetationDecreased soil bulk density, increased infiltration, and decreased erodibility
Soil erosionHigh erodibilityMulchRegrade vegetation
Soil moistureToo wetDrainWetland construction
Too dryOrganic mulchTolerant species Increased water retention due to surface area and charge characteristics

Nutritional MacronutrientsNitrogen deficiency
Other deficiencies
Fertilizer
Fertilizer
Nitrogen fixing plants, for example, leguminous trees or shrubs
Fertilizer, amendments,
tolerant species
Yield increases
Slow nutrient release
Soil organic matter stabilization
Retention of released nutrients
Increased microbial activity
Habitat for mychorrhizal fungi hyphae

Toxicity pHAcid soils (<4.5)LimeTolerant speciesDesigned for alkaline surface charge
Alkaline soils (>7.8)Pyritic waste, organic matterWeathering, tolerant speciesHigh CEC for Na retention
Heavy metalsHigh concentrationOrganic matter, tolerant cultivarInert covering, tolerant speciesHigh surface area and cation exchange capacity allows for metal retention
SalinityEC > 4 ds/m
pH < 8.5, SAR < 13
Gypsum, irrigationWeathering, tolerant speciesMixed with gypsum to reduce soil structural issues
SodicityEC < 4 ds/m,
pH > 8.5, SAR ≥ 13
Gypsum, irrigationWeathering, tolerant speciesNutritional values as described
High CEC for Na retention