Organic Materials and AMF Addition Promote Growth of Taxodium ‘zhongshanshan’ by Improving Soil Structure

Abstract

Soil salinization is considered a type of global-scale soil degradation, whereby excessive salinity severely diminishes soil health, which is primarily manifested through disrupted soil structures and reduced fertility. Furthermore, plant growth capacity is inhibited, and productivity is diminished. Consequently, the improvement of saline soils is regarded as a particularly important aspect of enhancing land production. To elucidate the roles of organic amendments and mycorrhizal fungi in the improvement of saline soils, seven treatments were set up, including biochar alone (B), straw alone (S), arbuscular mycorrhizal fungi alone (A), biochar in combination with arbuscular mycorrhizal fungi (BA), straw in combination with arbuscular mycorrhizal fungi (SA), and a control (CK). The results revealed that the seedling height growth rate under the BA treatment was significantly higher than that of the CK by 31.66%. The capillary porosity of the soil under the addition of BA was significantly higher than the CK by 3.17% in the 0–20 cm soil layer. The BA treatment reduced the fractal dimension of soil aggregates considerably by 19.06% in the 0–20 cm soil layer, and 13.71% in the 40–60 cm soil layer in contrast to the CK, respectively. In addition, the positive effects of the BA treatment were significant in the 20–40 cm soil layer. Overall, the application of biochar alone promoted the water stability of soil aggregates. The combination of arbuscular mycorrhizal fungi and biochar promoted plant growth, improved soil pore structures, promoted agglomerate water stability, and led to improved microbial activities. The results showed that organic amendments applied in conjunction with AMF improved the environment of salinized soil, which is a key factor in the promotion of plant growth and the long-term stability of soil health. This study provides a key technical basis for remediation of salinized soil.