Hydrochar from sugarcane industry by-products: assessment of its potential use as a soil conditioner by germination and growth of maize

Abstract

Background Hydrothermal carbonization (HTC) is a thermochemical process to convert biomass in carbon-rich materials (hydrochar). The use of sugarcane industry by-products in HTC has been evaluated, generating a hydrochar rich in nutrients, which could be used as a soil conditioner. We raised the hypothesis that the application of hydrochar in soil can improve its nutrient characteristics, bringing a better environment and favouring plant growth, expecting a development similar to that one observed in anthropogenic soils. Results Germination studies were performed expecting a species-dependent response, using maize and tomato seeds, whose development was assessed in two soluble fractions obtained from hydrochar aiming to evaluate different rhizosphere conditions. The results showed a better development of maize, especially in the aqueous soluble fraction, whose nutrient concentration was lower than that of the acid soluble fraction, as well as the organic composition. Maize growth in soils showed a better initial development in ultisol compared to oxisol, this being inferred by root:shoot biomass ratio and by scanning electron microscopy (SEM) images. However, the development of maize was better in anthropogenic soil compared to soils that received hydrochar. Conclusion The maize growth, compared with that carried out in anthropogenic soil, suggests that during the period evaluated the addition of hydrochar in soil did not have a negative effect upon maize development in its initial phase, and could have even favoured rooting in ultisol.

Impacts of kaolinite enrichment on biochar and hydrochar characterization, stability, toxicity, and maize germination and growth

“…In another study, Yang et al 129 stated that kaolinite composite with walnut shell derived biochar improved its surface and adsorptive characteristics and nutrient release capacity, which ultimately positively impacted plant growth. Fregolente et al 130 found positive impact of hydrochar application on root and shoot development and dry biomass production of maize. Therefore, the parameters of seed germination and seedling growth revealed positive impacts of the synthesized materials with varying proportions.…”

Lime-assisted hydrothermal humification and carbonization of sugar beet pulp: Unveiling the yield, quality, and phytotoxicity of products

“…HSs are known to plant growth hormones like indole acetic acid and gibberellins, boosting root elongation and nutrient adsorption (Yang et al, 2021). However, high concentrations of AHA can introduce phytotoxic compounds, affecting seedling and root growth (Fregolente et al, 2021). Despite not detecting catechol, phenol, or cresol, other phytotoxic elements might have influenced the results.…”

Post-Industrial Use of Sugarcane Ethanol Vinasse: A Systematic Review

“…In Raza et al [136], the authors demonstrate that the integrated use of various amendments, including vinasse, with chemical fertilization, improves soil properties and rice yield. The hydrothermal carbonization process using vinasse and sugarcane bagasse allows producing hydrocarbon [137].…”

“…Sector Industrial Application [56,58,66,[73][74][75]77,79,92,97,101,103,107,117,[135][136][137]144] Agriculture Soil remediation, crop improver (e.g., corn, tomato, rice), fertigation in sugar cane, fertilizer, among others [31,33,35,37,[39][40][41][42][43][44][45]48,49,52,55,59,62,63,69,71,72,76,81,82,[84][85][86]90,91,94,96,98,99,…”

“…[144]. While it has been used as an integral fertilizer and soil improver, for tomato crop growth [101], in addition to rice [136] and maize [137]. Finally, vinasse has been used as an improver in the yield of corn [135] and sugarcane [58].…”