Search

The replant disease refers to abnormal crop growth caused by continuous cultivation of the same or related species on the same soil, and often occurring in crops and orchards. Recently, replant disease have become a major factor constraining the sustainable development of global agriculture and fruit trees. The causes of replant disease include biological and abiotic factors, but in the final analysis, they are caused by changes in the soil environment. Soil environment is closely related to soil productivity. A decline of soil quality results in poor crop growth and reduced yield. The causes of soil environment changes mainly include intensive soil tillage, rapid industrialization, soil pollution, destruction of soil micro-ecosystem and substances secreted by plants under replant condition. Biochar, a porous carbon material prepared from pyrolysis of biomass (agricultural waste, etc.), is widely used as an amendment and adsorbent. To understand the role of biochar in alleviating replant disease, we summarized the previous research results of biochar application in replant soil. The following points are summarized: (1) soil problems and their effects on plants; (2) effects of biochar on replant soil environment; and (3) effects of biochar on alleviating replant disease. Overall, the literature suggests that biochar is an effective measure to amendment soil environment and alleviates replant disease. Further studies on biochar will enhance our understanding of biochar–soil interactions, and its long-term impact of biochar on soil environment. [ABSTRACT FROM AUTHOR]

Phloridzin is a phenolic acid associated with the genus Malus (Mill.) that causes apple replant disease. The removal of phloridzin is of great significance to alleviate this condition, and hence biochar was investigated for this purpose. The goal of this study was to improve the adsorption capacity of biochar for phloridzin by chemical modification. Biochar from apple branches and biochar modified with chitosan to were characterized by elemental analysis, Brunauer Emmett Teller analysis, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Batch adsorption experiments were employed to select the optimal biochar dosage and adsorption time. The results showed that biochar treated for 24 h at 6 g L−1 achieved best adsorption properties and that the chitosan-modified biochar provided a higher adsorption capacity than the unmodified material. The influence of pH upon the adsorption was studied and the results were fitted with isotherm and kinetic equations. The results showed that adsorption process corresponds to a Langmuir isotherm and pseudo-second-order kinetics. The qmax of the biochar was increased from 15.93 to 28.96 mg g−1 by modification with chitosan. The pH was shown to play an important role in the adsorption process. The adsorption of phloridzin to biochar was demonstrated to be a single-layer multiple component adsorption process based on chemisorption. This study provides a theoretical basis to alleviate apple replant disease. [ABSTRACT FROM AUTHOR]