Abstract:

Saline-alkali soil is prevalent in arid and semiarid areas of Dingbian county. The aim of this study was to determine whether adding desulfurization gypsum， fly ash， or a combination of these two materials can improve saline-alkali soil. Pot experiments were conducted with alfalfa （Medicago sativa） growing in saline-alkaline soil with 10 treatments， including a control （CK）， soil with the addition of desulfurization gypsum （1%， 2%， 4%； D₁， D₂， D₃）， soil with the addition of fly ash （1%， 2%， 4%； F₁， F₂， F₃）， and soil with the addition of mixture of desulfurization gypsum and fly ash （0.5%+0.5%， 1%+1%， 2%+2%； DF₁， DF₂， DF₃）. The salinity， sodicity， and nutrient profile of the soils and plant growth were analyzed. The results showed that the addition of desulfurization gypsum reduced the soil pH， increased the total phosphorus content in soil， and increased plant height and biomass. The contents of SO₄^2-， K⁺， Ca²⁺， and Mg²⁺ in soil increased with the addition of desulfurization gypsum. The addition of fly ash increased soil pH， SO₄^2?-， Ca²⁺， and total iron contents， decreased the soil K⁺ content， and resulted in decreased plant height and biomass. The mixture of desulfurization gypsum and fly ash significantly reduced the total iron content and increased the total P content in soil， but did not significantly affect plant growth. The results indicate that， compared with the addition of desulfurization gypsum and fly ash to saline-alkali soil， the addition of desulfurization gypsum alone more effectively improved soil quality and promoted plant growth. These results provide a scientific basis for the improvement of saline-alkali soil and for the comprehensive utilization of coal-based solid waste in arid and semiarid areas.

Key words: arid and semi-arid areas, soil nutrient, ion concentration, biomass