Influencing Factors of the Spatial–Temporal Variation of Layered Soils and Sediments Moistures and Infiltration Characteristics under Irrigation in a Desert Oasis by Deterministic Spatial Interpolation Methods

Abstract

Soil moisture is the main limiting factor for crop growth and the sustainable development of oases in arid desert areas. Therefore, the temporal and spatial variation and infiltration laws of oasis soil moisture should be studied. The objective of this study is to reveal the influencing factors of the spatial-temporal variation of layered soil and sediment moisture and infiltration characteristics under irrigation in desert oases. Hydraulic conductivities were measured using the double-ring infiltrometer, while the regional and site soil moistures were measured and calibrated using weighted method and neutron moisture meter. Deterministic spatial interpolation methods, including multiquadric radial basis function, inverse distance weighted, and local polynomial regression isogram, were adopted to map the regional distribution of hydraulic conductivities, spatial soil moistures, and spatial-temporal isogram of the point site soil moistures in Yaoba Oasis, respectively. Results showed that the leading influencing factors of the (1) regional spatial soil moisture were soil and sediment permeability, stream link direction, microclimate, and dewfalls; (2) spatial layered soil and sediment moistures were microclimate and dew condensation; and (3) spatial-temporal variation at the point site profiles were soil texture, water requirement, and preferential flow. Under irrigation, soil moisture increased significantly, in which the maximum increase was 10.8 times the original state, while the recharging depth substantially increased up to 580 cm with the preferential flow. The spatial-temporal variation of the soil moisture under irrigation indicated that the best irrigation frequency should be 15 days per time. Moreover, the infiltration process can be divided into the preferential flow, piston flow, and balanced infiltration stages.

Seasonal and Inter-Annual Variability of Groundwater and Their Responses to Climate Change and Human Activities in Arid and Desert Areas: A Case Study in Yaoba Oasis, Northwest China

“…Hence, the evaporation showed an insignificant increase afterwards from 1987.09 mm in 2007 to 2264.72 mm in 2018. According to previous research results, the intense evaporation in the arid region mostly exhausted the flood formed during the rainstorm season before it infiltrated into the groundwater [16,47]. In addition, water diversion and irrigation during the agricultural production increased the groundwater level and caused it to exceed the critical depth, resulting in continuous strong water evaporation in the shallow phreatic water area of the western part of study region, which worsened soil salinization [27,48,49].…”

Moisture Migration and Recharge Pattern of Low-Permeability Thick Cohesive Soil in Northern Margin of the Jianghan Plain

“…Cohesive soil water and solute transport studies not only consume a great deal of time but are also hard to do [11]. Various studies have attempted to use technologies such as hydrological geochemistry, stable isotopes, in situ monitoring, and numerical simulations to reveal the migration of soil moisture and the conversion relationships among rainfall, soil moisture, and groundwater [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28]. But almost all of these studies were located in arid and semi-arid areas with unconfined groundwater aquifers.…”

Hydrodynamic Behaviors and Geochemical Evolution of Groundwater for Irrigation in Yaoba Oasis, China

“…Excessive groundwater exploitation has already resulted in the instability of the ecosystem in these areas. In order to address the problems of groundwater quality deterioration and soil salinization in Yaoba Oasis, the Geological Brigade of the Hydrological Bureau of Inner Mongolia, Inner Mongolia Institute of Hydraulic Research, and Chang'an University conducted a thorough survey of the hydrogeology in Yaobao Oasis from 1980 to 2015 [19][20][21][22][23]. Some studies have evaluated the spatial and temporal evolution of water quality in reservoirs as well as the mechanisms of soil salinization.…”