The role of biochar and biochar-compost in improving soil quality and crop performance: A review

Drought and salt stress negatively affect soil fertility and plant growth. Application of biochar, carbon-rich material developed from combustion of biomass under no or limited oxygen supply, ameliorates the negative effects of drought and salt stress on plants. The biochar application increased the plant growth, biomass, and yield under either drought and/or salt stress and also increased photosynthesis, nutrient uptake, and modified gas exchange characteristics in drought and salt-stressed plants. Under drought stress, biochar increased the water holding capacity of soil and improved the physical and biological properties of soils. Under salt stress, biochar decreased Na+ uptake, while increased K+ uptake by plants. Biochar-mediated increase in salt tolerance of plants is primarily associated with improvement in soil properties, thus increasing plant water status, reduction of Na+ uptake, increasing uptake of minerals, and regulation of stomatal conductance and phytohormones. This review highlights both the potential of biochar in alleviating drought and salt stress in plants and future prospect of the role of biochar under drought and salt stress in plants.

Biochar soil amendment on alleviation of drought and salt stress in plants: a critical review

Benefits and limitations of biochar amendment in agricultural soils: A review

This review summarizes the influences of pyrolysis conditions and feedstock types on biochar properties, and how biochar properties in turn affect soil properties. Mechanistic evidence of biochar's potential for enhancing crop productivity, carbon sequestration, and nutrient use efficiency are also discussed. The review identifies the knowledge gaps, limitations, and future research directions for large-scale use of biochar. Both pyrolytic parameters and feedstock types are considered to be the main factors controlling biochar properties such as nutrient content, recalcitrance and pH. Biochar produced at low temperatures may improve nutrient availability and crop yield in acidic and alkaline soils, whereas high-temperature biochar may enhance long-term soil carbon sequestration. Biochar can also improve the efficiency of inorganic and organic fertilizers by enhancing microbial functions and reducing nutrient loss, thereby making nutrients more available to plants. Integration of biochar and chemical or organic fertilizers generally provides for better nutrient management and crop yield in most types of soils. Although biochar can improve degraded soils, it is not a panacea; as such, soil- and crop-specific biochar are needed in order to ensure optimum crop yield and agricultural sustainability.

Impact of Biochar Properties on Soil Conditions and Agricultural Sustainability: A Review

Soil health is essential and irreplaceable for plant growth and global food production, which has been threatened by climate change and soil degradation. Degraded coastal soils are urgently required to reclaim using new sustainable technologies. Interest in applying biochar to improve soil health and promote crop yield has rapidly increased because of its multiple benefits. However, effects of biochar addition on the saline–sodic coastal soil health and halophyte growth were poorly understood. Response of two halophytes, Sesbania (Sesbania cannabina) and Seashore mallow (Kosteletzkya virginica), to the individual or co-application of biochar and inorganic fertilizer into a coastal soil was investigated using a 52 d pot experiment. The biochar alone or co-application stimulated the plant growth (germination, root development, and biomass), primarily attributed to the enhanced nutrient availability from the biochar-improved soil health. Additionally, the promoted microbial activities and bacterial community shift towards the beneficial taxa (e.g. Pseudomonas and Bacillus) in the rhizosphere also contributed to the enhanced plant growth and biomass. Our findings showed the promising significance because biochar added at an optimal level (≤5%) could be a feasible option to reclaim the degraded coastal soil, enhance plant growth and production, and increase soil health and food security.

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G. Valboa

Papers

Biochar stimulates plant growth but not fruit yield of processing tomato in a fertile soil