While biochar use in agriculture is widely advocated, how the effect of biochar on plant growth varies with biochar forms and crop genotypes is poorly addressed. The role of dissolvable organic matter (DOM) in plant growth has been increasingly addressed for crop production with biochar. In this study, a hydroponic culture of rice seedling growth of two cultivars was treated with bulk mass (DOM-containing), water extract (DOM only), and extracted residue (DOM-free) of maize residue biochar, at a volumetric dosage of 0.01, 0.05, and 0.1%, respectively. On seedling root growth of the two cultivars, bulk biochar exerted a generally negative effect, while the biochar extract had a consistently positive effect across the application dosages. Differently, the extracted biochar showed a contrasting effect between genotypes. In another hydroponic culture with Wuyunjing 7 treated with biochar extract at sequential dosages, seedling growth was promoted by 95% at 0.01% dosage but by 26% at 0.1% dosage, explained with the great promotion of secondary roots rather than of primary roots. Such effects were likely explained by low molecular weight organic acids and nanoparticles contained in the biochar DOM. This study highlights the importance of biochar DOM and crop genotype when evaluating the effect of biochar on plants. The use of low dosage of biochar DOM could help farmers to adopt biochar technology as a solution for agricultural sustainability.

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Objective. To investigate the effects of recombinant human epidermal growth factor eye drops combined with phacoemulsification on short- and long-term visual acuity recovery and related dry eye complications in patients with senile cataract. Methods. Sixty patients with senile cataract cured from January 2019 to January 2021 were enrolled in our hospital. The patients in the control group were arbitrarily assigned into the control and the research group. The former group received phacoemulsification, and the latter group received recombinant human epidermal growth factor (RhEGF) eye drops combined with phacoemulsification. The curative effect, the incidence of xerophthalmia, short-term and long-term vision improvement, changes of corneal endothelial cells, serum factors, and life quality scores were compared. Results. The effective rate of the research group was 90.00%, and the effective rate of the control group was 66.67%; the curative effect of the research group was higher than that of the control group ( P < 0.05 ). The incidence of dry eye in the research group was lower than that in the control group ( P < 0.05 ). The short-term and long-term visual acuity improvement effect of the research group was better than that of the control group ( P < 0.05 ). After treatment, the density of corneal endothelial cells in the research group was higher than that in the control group, while the proportion of hexagonal cells and the coefficient of variation of corneal endothelial cells in the research group were lower than those in the control group ( P < 0.05 ). After treatment, IL-6 and TNF-α in the research group were lower than those in the control group ( P < 0.05 ). Compared with the control group, the physical function, psychological function, social function, and healthy self-cognition scores of the research group were all lower ( P < 0.05 ). Conclusion. Cataract is the leading cause of blindness in the world. With the continuous improvement of cataract phacoemulsification technology, the incidence of some serious complications has gradually lessened. Xerophthalmia is one of the most obvious and predictable complications after cataract surgery and may affect the recovery of postoperative visual acuity. Recombinant human epidermal growth factor eye drops can effectively enhance the visual acuity of patients, promote the curative effect, and strengthen the life quality.

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