Mechanism of Saline–Alkali land improvement using subsurface pipe and vertical well drainage measures and its response to agricultural soil ecosystem.

Salinization is recognized as a threat to agricultural productivity and land resources in global arid desert regions. To date, field soil improvement schemes have met with minimal success to date. We aimed to improve saline–alkali soils by assessing the effects of combining subsurface pipe (P a) and vertical well (S a) drainage measures on agricultural soils ecosystem. In a five-year field experiment, soil was sampled 0.5 m, 5 m, 7.5 m horizontally away from the P a , and 0.5 m, 30 m, 60 m horizontally away from the S a. Findings indicate that the soil electrical conductivity (EC) decreased from 16 dS m⁻¹ to 3 dS m⁻¹ at a 0–80 cm depth, and the soil desalination efficiency was great at the 0–300 cm depths (≥ 32%) than at the 400–700 cm depths (−14%–74.7%). The combined P a and S a drainage measures significantly decreased the species richness and quantity of soil microbial communities, and their negative impact on observed species was irreversible within 1 year. The farther the horizontal sampling conducted from the P a and S a , the greater the structural similarity of the microbial community at the genus level, higher the catalase, acidic protease, and neutral phosphatase activities, and lower the alkaline phosphatase activity. The overall decrease in groundwater level from 2016 to 2020 was 5.7 m. The seed cotton yield increased by 3.2 t ha⁻¹. The results suggest that the value of saline–alkali soil can be improved by combining P a and S a drainage measures. Our research provides guidance for further effective utilization of agricultural water and soil resources and the sustainable development of the soil ecosystem in arid desert areas. [Display omitted] • Use drainage measures to improve the saline–alkali soil in agricultural ecosystem. • The cheapest way for reclamation of saline alkali soil is leaching of salts by irrigation water. • Salt discharge were positively correlated with the decrease of groundwater level and soil EC. • The farther away from drainage measures, the greater the similarity bacteria community. • The soil desalination rate of 0–300 cm depths was greater than 400–700 cm depths. [ABSTRACT FROM AUTHOR]