The Role of Biochar in Ameliorating Disturbed Soils and Sequestering Soil Carbon in Tropical Agricultural Production Systems

Table 2

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

Limiting factor	Variable	Problem	Short-term treatment	Long-term treatment	Role of biochar
Physical	Soil structure	Soil too compact	Rip or scarify	Vegetation	Decreased soil bulk density, increased infiltration, and decreased erodibility
	Soil erosion	High erodibility	Mulch	Regrade vegetation
	Soil moisture	Too wet	Drain	Wetland construction
		Too dry	Organic mulch	Tolerant species	Increased water retention due to surface area and charge characteristics
Nutritional	Macronutrients	Nitrogen 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	pH	Acid soils (<4.5)	Lime	Tolerant species	Designed for alkaline surface charge
		Alkaline soils (>7.8)	Pyritic waste, organic matter	Weathering, tolerant species	High CEC for Na retention
	Heavy metals	High concentration	Organic matter, tolerant cultivar	Inert covering, tolerant species	High surface area and cation exchange capacity allows for metal retention
	Salinity	EC > 4 ds/m; pH < 8.5, SAR < 13	Gypsum, irrigation	Weathering, tolerant species	Mixed with gypsum to reduce soil structural issues
	Sodicity	EC < 4 ds/m,; pH > 8.5, SAR ≥ 13	Gypsum, irrigation	Weathering, tolerant species	Nutritional values as described; High CEC for Na retention