Biochar and its importance on nutrient dynamics in soil and plant

Abstract

Biochar, an environmentally friendly soil conditioner, is produced using several thermochemical processes. It has unique characteristics like high surface area, porosity, and surface charges. This paper reviews the fertilizer value of biochar, and its effects on soil properties, and nutrient use efficiency of crops. Biochar serves as an important source of plant nutrients, especially nitrogen in biochar produced from manures and wastes at low temperature (≤ 400 °C). The phosphorus, potassium, and other nutrient contents are higher in manure/waste biochars than those in crop residues and woody biochars. The nutrient contents and pH of biochar are positively correlated with pyrolysis temperature, except for nitrogen content. Biochar improves the nutrient retention capacity of soil, which depends on porosity and surface charge of biochar. Biochar increases nitrogen retention in soil by reducing leaching and gaseous loss, and also increases phosphorus availability by decreasing the leaching process in soil. However, for potassium and other nutrients, biochar shows inconsistent (positive and negative) impacts on soil. After addition of biochar, porosity, aggregate stability, and amount of water held in soil increase and bulk density decreases. Mostly, biochar increases soil pH and, thus, influences nutrient availability for plants. Biochar also alters soil biological properties by increasing microbial populations, enzyme activity, soil respiration, and microbial biomass. Finally, nutrient use efficiency and nutrient uptake improve with the application of biochar to soil. Thus, biochar can be a potential nutrient reservoir for plants and a good amendment to improve soil properties.

Surface-applied or incorporated biochar and compost combination improves soil fertility, Chinese cabbage and papaya biomass

“…Chinese cabbage has a high requirement for K (Berek et al 2018;van Averbeke et al 2007) and it was determined that at harvest, the control plants had insufficient K concentrations (Jones et al 1991). The outlier of higher soil K in the 0-10 cm for the SBC than the control, in the Oxisol, could not be explained by plant response, and is another example of inconsistent K to biochar (Hossain et al 2020).…”

Effects and Economic Sustainability of Biochar Application on Corn Production in a Mediterranean Climate

“…The findings of this study indicated that B1 supplementation increases the Mg content. The increased availability of Ca and Mg in the soil promotes crop production [ 18 , 50 ].…”

The Evolution of Soilless Systems towards Ecological Sustainability in the Perspective of a Circular Economy. Is It Really the Opposite of Organic Agriculture?

“…Strategies to overcome the problem consist in collecting rainwater from greenhouses or applying some technologies to improve the quality of the available water [6]. Other solutions may come from different approaches; for example, the use of zeolite, expanded clay or biochar as substrates contributes to the removal of Na + thanks to their cation exchange capacity, increasing the availability of Ca 2+ and Mg 2+ in substitution of sodium [11,12]. The use of properly treated wastewater, both from soilless and municipal wastewater, can contribute to save freshwater [13,14].…”

“…In this context, one significant point is that the processing costs can be externalized (held by the energy producer) instead of being charged by the growing media manufacturer [17]. Biochar is a source of organic matter, nitrogen and other nutrients that can be beneficial for use as growing substrate [12,[18][19][20]. The initial nutrient content and its rate of release into the nutrient solution should be computed in the final nutrient supply count.…”

“…This could suggest that it can be stable after recycling in successive growing cycles. A negative feature can be high alkalinity [12,19,22,25].…”