Abstract:
Objective The aim was to study the effect of different chemical amendments and their application doses on the improvement of salinization parameters of saline-alkali soil and the growth of wheat.
Method The saline-alkali soil as the contrast, five chemical reagents (oxalic acid, calcium sulfate, aluminum sulfate, ammonium sulfate, potassium sulfate) and four dosages (soil mass ratio 0.075% , 0.15% , 0.3% , 0.6%) were composited to 21 treatments. Ice wheat was used as an indicator crop to evaluate the improvement effect of chemical reagents on saline-alkali soil.
Result The results indicated that soil pH and exchangeable sodium saturation percentage (ESP) decreased with the increase of five reagents, but soil electrical conductivity (EC) value and cation exchange capacity (CEC) were opposite. Among them, 0.6% aluminum sulfate and calcium sulfate had the largest decrease in ESP, and 0.6% aluminum sulfate, oxalic acid and potassium sulfate had the lowest pH value. The contents of soil available nitrogen, available potassium and available phosphorus increased with increasing dosage of oxalic acid, calcium sulfate, aluminum sulfate and potassium sulfate. The biomass accumulation of wheat in saline-alkali soil treated with 0.075% oxalic acid and 0.15%, 0.3%, 0.6% aluminum sulfate was significantly higher than that in saline-alkali soil. The results of random forest analysis showed that available potassium, available nitrogen, pH and CEC were important factors affecting the wheat growth. Structural equation modeling (SEM) analysis showed that different chemical amendments and application doses may indirectly affect wheat growth by reducing pH, increasing CEC and then increasing soil nutrients.
Conclusion The application of 0.6% aluminium sulphate in the Songnen Plain has the potential to significantly improve the ecology of the saline-alkali soil. The application of 0.075% oxalic acid and 0.15%, 0.3%, 0.6% aluminum sulfate as chemical modifiers can increase the land biomass and improve the ecological protection, to strengthen the protection of black land and food production security.