Effects of flue gas desulfurization gypsum and clover planting on qualities of soil and winter jujube in coastal saline-alkali orchard of north China

Flue gas desulfurization gypsum and clover planting alleviated the soil salinization stress. Soil pH and total phosphorus affected the bacterial communities. Total phosphorus affected the fungal communities. Flue gas desulfurization gypsum and clover planting improved jujube quality. The coastal area of Shandong Province, characterized by coastal saline tidal soil, is one of the main production areas of winter jujube in China. However, the low soil fertility and poor soil structure in jujube orchard restricted the development of the jujube industry. The objectives of this study were to 1) evaluate the effect of application of flue gas desulfurization (FGD) gypsum and clover planting on soil quality improvement and soil microbial community structure of jujube orchard; 2) investigate the effects of two measures on the nutrition and quality of winter jujube. The results showed that FGD gypsum reduced the soil total salt content by 65.6%, and clover planting increased the soil organic matter content by 30.7%, which effectively alleviated the soil salinization stress and improved the soil structure. Soil pH and total phosphorus (TP) were the main determinants influencing bacterial community composition, and TP was the dominant factor of the fungal community composition in the saline-alkali soils. Meanwhile, FGD gypsum addition and clover planting significantly increased the sugar degree and Vc content of winter jujube, thus improved jujube quality, and further contributed to the ecological sustainable development of winter jujube industry.