功能真菌-除杂磷石膏复合改良剂在滨海盐碱土中的修复应用OA

High pH and salinity in coastal saline-alkali soil cause severe deficiencies in available phosphorus,hindering ecological restoration and farmland expansion.Herein,we used moderately saline coastal soils in Rudong to evaluate the combined effects of functional fungus and phosphogypsum on soil pH,soil available phosphorus,and microbial activity.Phosphorus-solubilizing fungi(CCTCC M2023240)was optimized through liquid shake flask experiments.Six treatments(CK,PG,ANG,ANG+PG,NS,NS+PG)were established and cultured at a constant temperature for 30 days indoors.As a result,the fungus exhibited continuously increasing respiratory intensity within the 0-8％NaCl range but lost activity at 16％salinity.More importantly,organic acids were constantly produced to solubilize phosphorus under saline stress.In soil culture tests,the addition of phosphogypsum(PG)and Aspergillus niger(ANG)could significantly lower the soil pH.Meanwhile,phosphogypsum addition markedly increased soil available phosphorus content.Notably,the fungal-phosphogypsum(ANG+PG)composite treatment led to the lowest soil pH of 7.29,with available phosphorus at 31.8 mg/kg,indicating no significant difference compared to the application of purified phosphogypsum alone.However,the nutrients from phosphogypsum enhanced the respiratory intensity of Aspergillus niger and prolonged its survival time.According to scanning electron microscopy(SEM),Aspergillus niger could grow in saline-alkali soil and survive under such conditions,suggesting its potential for saline-alkali soil remediation.Our research work demonstrated that the Aspergillus niger-phosphogypsum composite soil conditioner could reduce salinity and enhance phosphorus availability,and it will provide a theoretical basis and technological prototype for coastal saline-alkali land remediation and high-value utilization of solid waste phosphogypsum.