Biochar from crop residues such as corncobs can be used for soil amendment, but its negative effects have also been reported. This study aims to evaluate the phytotoxic effects of different biochar treatments and application rates on cress (Lepidium sativum). Corncob biochar was produced via slow pyrolysis without using purging gas. Biochar treatments included fresh biochar (FB), dried biochar (DB), washed biochar (WB), and biochar water extract (WE). Biochar application rates of 10, 20, and 30 t/ha were investigated. Significant phytotoxic effects of biochar were observed on germination rates, shoot length, fresh weight, and dry matter content, while severe toxic effects were identified in FB and WE treatments. Germination rate after 48 h (GR₄₈) decreased with the increase of biochar application rates in all treatments. The observed order of performance of the biochar treatments for germination, shoot length, and shoot fresh weight for every biochar application rate was WB>DB>WE>FB, while it was the reverse order for the shoot dry matter content. WB treatment showed the best performance in reducing the phytotoxicity of biochar. The mitigation of the phytotoxicity in fresh corncob biochar by washing and heat treatment was found to be a simple and effective method.

Biochars have long been associated with elevating plant productivity. An increasing number of studies, however, report that char application might also impair plant nutrient availability and reduce yields. In particular, char accompanying compounds as well as a hypothesized immobilization of nitrogen have been identified as playing a significant role in possibly diminishing plant productivity following char application. Herein, we tested the fertilizing effects of modified biochars in order to derive knowledge required to develop tailor-made chars, which predictably affect plant nutrition. Slow-pyrolysis maize cob biochar was modified by washing with either ethanol or hydrochloric acid to remove ash and organic compounds or by loading it with nutrient-rich residues in the form of digestate from the bioenergy sector. Maize plants were grown for 35 days on biochar-amended sand. We analyzed both substrate properties (pH, total carbon, and nitrogen, available magnesium and potassium) and plant functional traits (biomass, leaf area, root to shoot ratio, specific leaf area). Our results suggest that total plant biomass production remained unaffected by the application of biochar and its washed forms. Contrastingly, nutrient-loaded biochar induced a significant increase in productivity at similar nutrient levels due to improved plant nutrient uptake. Further research is required to understand the role of biochar modifications that facilitated improvements in plant productivity.

Coffee fruit production is an important agricultural sector in more than 70 tropical countries. However, the production of fruit spirits based on coffee fruits has not been investigated to date. This study evaluated, for the first time, its fermentation and distillation performance, ethanol yield and sensorial attributes. A selected yeast strain (Saccharomyces cerevisiae L.) fermented coffee cherry mash within five days and produced ethanol concentrations of 31.0 g/L. The mash was distilled and distillate fractions were categorized for heads/hearts/tails by sensory evaluation, resulting in an ethanol mass ratio of 1.0:4.2:0.8 with a total yield of 1.8% (w/w) ethanol based on coffee cherry mash. Analysis of fermentative volatiles indicated comparatively high methanol contents of 26 ± 4 g/L ethanol in the hearts fraction. Sensory evaluation of the hearts fraction resulted in 15 spirit specific descriptors, with vegetal and nutty indicating the most important terms to describe the perception of coffee cherry spirit. The results suggested that there is a high potential to introduce a fruit spirit based on coffee fruits.

Sesame oil is a food and energy resource that is not used enough. Sedimentation of crude oil after pressing can remove particles and happens regardless of the producer’s intention. However, sedimentation of crude plant oil and its sensing technology are rarely studied. This research studied crude sesame oil sedimentation and monitored it with low-cost laser backscattering imaging (LBI). In the discontinuous measurement, a 30-day sedimentation was conducted with oil samples sent to the lab LBI system for image capture. A scattering spot and an increasing Tyndall effect along the light path were seen. In the continuous measurement, an LBI system was mounted on a sedimentation tank for 30 days. The sedimentation curve, scattering images, and oil properties were checked. The sedimentation speed was about −7 mm/h, then less than −2 mm/h. The image features correlated well with the sedimentation interface height (R² = 0.97) when the height was above −100 mm. The oil-particle-related properties (ash content, phosphorus content, carbon residue, and total contamination) dropped by at least 87%, water content decreased by 90%, and the oxidation-related properties (oxidation stability, γ-tocotrienol, δ-tocopherol, γ-tocopherol, and acid value) changed less significantly. The crude sesame oil sedimentation had two stages: diluted and hindered sedimentation. This research can help improve sedimentation tank and LBI system design and prevent unwanted sedimentation.