Impact of biochar‐based slow‐release N‐fertilizers on maize growth and nitrogen recovery efficiency

Abstract

Biochar has been used to address several environmental problems and may be efficacious as a carrier of N‐fertilizer in slow‐release N‐fertilizer (SRF) formulations. Our objective was to compare the efficacy of SRF pellets formulated with different mass ratios of biochar and urea with traditional N‐fertilizers for improving N use efficiency by maize (Zea mays L.) grown under greenhouse conditions. Two different soil types, four SRF formulations with different biochar‐to‐urea (BCN) ratios (1:2 BCN, 1:3 BCN, 1:4 BCN, and 1:6 BCN), three traditional N‐fertilizers (urea, urea ammonium nitrate, and S‐coated urea), and unfertilized controls for each soil were tested. The accelerated urea release test showed significantly less loss of urea for the SRF over time than the traditional N‐fertilizers. The biochar‐based SRF formulations significantly (p < 0.05) decreased nitrate leaching loss for both soils relative to the traditional fertilizers. All the SRF formulations increased maize shoot (1%–34%) and root (0%–23%) biomass, N‐recovery efficiency (17%–50%), and soil potential mineralizable‐N relative to urea and S‐coated urea. The results also indicate that the BCN ratio in the SRF formulation can be used to influence the timing of N release and plant N uptake. The results of the greenhouse study suggest that biochar‐based SRFs have potential agronomic and environmental benefits; however, more research is needed to assess their agronomic value under field conditions.

More N fertilizer, more maize, and less alfalfa: maize benefits from its higher N uptake per unit root length

“…N recovery efficiency was calculated as the difference in total plant content of N between a test treatment and the N0 treatment divided by the difference in the amount of N applied between the test treatment and the N0 treatment ( Banik et al., 2023 ). N utilization efficiency, which is defined as plant biomass production per unit of N uptake ( Haque et al., 2022 ), was calculated as total plant dry mass [shoot dry mass (SDM) plus root dry mass (RDM)] per pot divided by total plant content of N per pot in this study ( Dhaka et al, 2020 ).…”

Biochar – a sustainable soil conditioner for improving soil health, crop production and environment under changing climate: a review

“…However, in the context of global climate change, its consequences on soil health and agricultural production have become more significant (2). Adopting suitable crops, fertilization techniques, pest management protocols, and irrigation practices typically leads to high yields, which strengthens food security and ensures nutritional adequacy (3). Despite high production, farmers remain worried about a problem linked to the existing high-intensive agricultural production systems.…”

“…The conversion of agricultural residues and agroforestry byproducts into biochar through a thermo-chemical process, specifically pyrolysis, emerges as an alternative avenue for managing and disposing of surplus agricultural waste with enhanced efficiency (6). Pyrolysis is the chemical breakdown of a substance under oxygen-devoid conditions at extremely high temperatures (3). To make biochar an affordable and cost-effective soil conditioner, a farmer-centric approach which facilitates farmers to produce biochar themselves from agricultural residues by adopting low-cost biochar production techniques (7).…”

“…Furthermore, biochar application increases nutrient availability in the soil, thus contributing to improved nutrient availability for plants (3). Additionally, biochar carries organic substances and nutrients within its matrix.…”

Synthesis of biochar‐embedded slow‐release nitrogen fertilizers: Mesocosm and field scale evaluation for nitrogen use efficiency, growth and rice yield

“…Most slow‐release synthetic coating materials are non‐degradable and may even degrade soil structure, limiting microbial activity and impairing soil nutrient cycling and plant growth (Zhang et al, 2019). The alternative to synthetic coating material is organic materials and one such option is biochar, which is a carbonaceous and porous natural material created by pyrolysis of organic waste and environmentally friendly soil amendment (Banik et al, 2023; Hossain et al, 2020). It has a large surface area, pore volume and multi‐functional groups that support its use as a coating material for slow nutrient release and as a fertilizer carrier (Dong et al, 2020; Wang et al, 2017).…”