Study on Application Effect of Earthworm Manure on Tobacco in Hengnan

Objective] This study was conducted to investigate the effect of earth-worm manure on agronomic traits, yield and quality of flue-cured tobacco. [Method] A field experiment was carried out to investigate the effects of different amount of earthworm manure on growth and economic benefit of tobacco. [Result] The results showed that： the application of earthworm manure could promote vegetative growth of tobacco to different degrees, and significantly increase high-grade tobacco yield and output value, thereby increasing the total output value of tobacco. Among the different application amounts, basal application of earthworm manure 4 500 kg/hm2 could significantly increase the proportion of high-grade tobacco and tobacco output, improve benefit and maintain sustainable production capacity. [Conclusion] This study provides a theoretical basis for the improvement of tobacco-planting soil with earth-worm manure.

Immobilization of Cu2+and Cd2+by earthworm manure derived biochar in acidic circumstance

Earthworm manure, the by-product obtained from the disposing of biowastes by earthworm breeding, is largely produced and employed as a feedstock for biochar preparation through pyrolysis. For repairing acidic soil or acidic electroplating effluent, biochar physicochemical properties would suffer from some changes like an acidic washing process, which hence affected its application functions. Pristine biochar （UBC） from pyrolysis of earthworm manure at 700℃ and biochar treated by HCI （WBC） were comparatively investigated regarding their physicochemical properties, adsorption capability and adsorption mechanism of Cu2＋ and Cd2＋ from aqueous solution to explore the immobilization characteristics of biochar in acidic environment. After HCI treatment, the soluble ash content and phenolic-OH in the WBC sample was notably decreased against the increase of the carboxyl C=O, aromatic C=C and Si-O-Si, compared to that of UBC. All adsorption processes can be well described by Langmuir isotherm model. The calculated maximum adsorption capacity of Cu2＋ and Cd2＋ adsorption on UBC were 36.56 and 29.31 mg/g, respectively, which were higher than that of WBC （8.64 and 12.81 rag/g, respectively）, indicating that HCI treatment significantly decreased biochar adsorption ability. Mechanism analysis revealed that alkali and alkaline earth metallic, salts （carbonates, phosphates and silicates）, and surface functional groups were responsible for UBC adsorption, corresponding to ion exchange, precipitation and complexation, respectively. However, ion exchange made little contributions to WBC adsorption due to the great loss of soluble ash content. WBC adsorption was mainly attributed to the abundant exposure of silicates and surface functional groups （carboxyl C=O and aromatic C=C）.