Water and Salinity Variation along the Soil Profile and Groundwater Dynamics of a Fallow Cropland System in the Hetao Irrigation District, China

Abstract

Managing soil salinity has always been a difficult problem for agriculture. Balancing water and salt while maintaining crop quality and yield is a key issue for agricultural sustainability. The Hetao lrrigation District in China has a complex mix of cultivated and uncultivated land which plays a crucial role in soil salinization processes. To investigate the dynamic properties of soil moisture and salinity, soil ions and groundwater, cultivated and fallow soils in the Hetao lrrigation District were analyzed, side by side, using a combination of field and laboratory tests, with data processed using univariate and multivariate statistical approaches. The results showed that soil moisture increased with increasing soil depth in both cultivated and fallow soils. Salinity showed an increasing trend in 2022 and 2023 from April to September. The soil ions were mainly sulfate in the cultivated soils and chloride in the fallow soils. The characteristic factors affecting salt accumulation in cultivated soils are Na++K+, Cl−, SSC, SO42−, HCO3−, and pH, and the characteristic factors affecting salt accumulation in fallow soils are Na++K+, Cl−, SSC, HCO3−, and pH. Water table depth varied with irrigation and precipitation and was strongly influenced by external environmental factors. Groundwater salinity remained stable throughout the study period. This study provides a theoretical basis for the prevention and control of soil salinization in arid and semiarid areas through the “dry drainage salt” measure.

Effect of Water Conservation and Nitrogen Reduction on Root Growth and Yield in Spring Maize in Typical Sand Interlayered Soil

“…In the study by Zou, the maximum rooting depth of maize roots at the grain filling stage was 100 cm, whereas the maximum rooting depth was limited to the depth of the sand layer in the present study. Generally, roots increase their surface area to absorb water and nutrients to meet the normal growth needs of crops [58][59][60][61]. In this study, we found that RL in the horizontal and vertical directions was significantly correlated with yield and WUE, with the highest correlation observed in NR20.…”

Spatiotemporal Absorption Features of Yellow Willow Water Usage on the Southern Edge of the Semi-Arid Hunshandak Sandland in China

“…Under the assumption that temperature, humidity, and wind speed are all equal, solar radiation increased the evaporation intensity. The increased evapotranspiration intensity and the lower water content of the soil increased the water uptake initiative of the yellow willow on the sunny side and exacerbated water demand on the sunny side [37,[46][47][48].…”

Water, Salt, and Ion Transport and Its Response to Water-Saving Irrigation in the Hetao Irrigation District Based on the SWAT-Salt Model

“…Furthermore, based on the ion concentration changes in the Yellow River water over an extended period, it is possible to predict and analyze the changes in water salt in the HID in the future when the salt ion composition of the irrigation water changes. Second, the effects of irrigation with brackish water on the soil environment in the HID have already been studied by academics [27,[46][47][48], which can alleviate the risk of the secondary salinization of the soil to a certain extent. Accordingly, the SWAT-Salt model can consider the spatial distribution of saline water in the HID, the amount of extracted water, water quality, and other factors to further explore the impact of combined saline and freshwater irrigation on salt recharge and drainage balance in the HID at the watershed scale.…”