Effects of Mixed Application of Wood Vinegar and Biochar on Cadmium Absorption of Pakchoi under Different Concentrations of Cadmium Stress

Abstract

Because of its characteristics, wood vinegar is widely used in agricultural production processes. Wood vinegar can be used as a strong antioxidant, anti-bacteria, plant growth agent, an insecticide, and currently shows superiority in the treatment of heavy metals. Wood vinegar contains organic acids, organic compounds, and phenol, which can effectively adsorb heavy metals. A large number of studies have been conducted on the adsorption of heavy metals by biochar, but few studies have analyzed the effects of biochar and wood vinegar fertilization on the growth of cadmium soil genus plants and changes in soil heavy metal forms. This article analyzed the effects of wood vinegar and biochar mixed fertilizer on the growth and plant efficacy of pakchoi from the properties of wood vinegar, and confirmed that 0.75% wood vinegar liquid treatment is the most effective concentration. By analyzing the effectiveness of 0.75% wood vinegar and biochar mixture and single fertilization, the combined application of biochar + wood vinegar reduced the absorption rate of cadmium by pakchoi leaves and roots by 12.8% and 13.1% compared with the single treatment group. The yield of crops increased by 111.9~150.1%. The results of evaluating the enrichment coefficient and single-factor index are 0.17~0.67%, 0.005-0.008, and the ranking is D> E> C> B> A> CK. When observing the changes in soil morphology, the content of residual cadmium, carbonate-bound cadmium, and iron-manganese oxide-bound cadmium increased by 0.3~233.7 times, and the exchangeable cadmium content and the content of organic and sulfide-bound cadmium were reduced to 1.0~6.6 times. It can be seen that under different cadmium stress conditions, the mixed fertilization of wood vinegar and biochar will reduce the growth of pakchoi and the plant availability of cadmium, and it has a higher mitigation effect on cadmium soil pollution.