Evaluating the effects of layered soils on water flow, solute transport, and crop growth with a coupled agro-eco-hydrological model

Shuai Chen,Xiaomin Mao,Manoj K Shukla

doi:10.1007/s11368-020-02647-7

Shuai Chen, Xiaomin Mao + Show 1 more

Open Access

https://doi.org/10.1007/s11368-020-02647-7

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Abstract

PurposeSoil salinization and degradation in the arid and semiarid areas are a worldwide phenomenon. Soil capping with capillary barriers is a potential practice to hydraulically isolate contaminated soils, which may improve the soil environment for plant growth. This study aims to investigate the influences of soil capping on crop growth and soil salinization control in the arid area with shallow groundwater tables.Materials and methodsA one-dimensional agro-eco-hydrological model, LAWSTAC, capable of simulating water and solute transport in layered soil coupled with crop growth, was applied for simulating sunflower growth under field condition in Arid Northwest China. The model was calibrated and validated with the experimental data of 2012 and 2013 crop seasons. The calibrated model was then used to explore how the soil capping consisting of combinations of fine soil (10, 15, 17, 19, and 20 cm thick) and coarse sand (10, 5, 3, 1, and 0 cm thick correspondingly) would influence the soil water and salt dynamics, and seed yield.Results and discussionSimulation results by LAWSTAC compared well with the observed soil water content, salt concentration, leaf area index, and seed yield. Further scenario simulations showed that a sand layer in the soil capping could greatly affect the water and salt distribution in the soil above and below the sand layer. Though soil capping could decrease the water storage (WS) in the root zone, it caused no obvious increase in water stress to root uptake for sand thickness of 1–3 cm and also considerably reduced the root zone salt content (SC) in crop season compared with that without soil capping. The average WS during the crop season showed a negative correlation with the thickness of sand layer in the soil capping. The average SC from planting to harvest was significantly lower for thicker sand in the soil capping. To soils with high background salinization, the increase of sand thickness would be helpful for enhancing seed yield, until it reached a critical value.ConclusionsCoarse soil layer in the soil capping could prevent salt moving into the root zone, while fine soil could supply water to plant once water in coarse soil was low. Thus, in a long run, the soil capping consisting of combinations of fine and coarse soils with certain thicknesses would be an alternative practice for saline soil reclamation and improving crop production in arid area with shallow groundwater tables and soil salinization.

Highlights

Water shortage and soil salinity are major concerns for agricultural development in the arid and semiarid regions of the world (Askri et al 2014; Ghamarnia and Jalili 2014)
The calibrated model was used to explore how the soil capping consisting of combinations of fine soil (10, 15, 17, 19, and 20 cm thick) and coarse sand (10, 5, 3, 1, and 0 cm thick correspondingly) would influence the soil water and salt dynamics, and seed yield
In a long run, the soil capping consisting of combinations of fine and coarse soils with certain thicknesses would be an alternative practice for saline soil reclamation and improving crop production in arid area with shallow groundwater tables and soil salinization

Summary

Introduction

Water shortage and soil salinity are major concerns for agricultural development in the arid and semiarid regions of the world (Askri et al 2014; Ghamarnia and Jalili 2014). Research results showed that the textures, thicknesses, and locations of soil layers in vertical profile have distinct effects on water and salt dynamics in the crop root zone, and on the crop productivity (He et al 2013; Predelus et al 2015). This influence presents on water flow and on the soil water and salt storage (Ityel et al 2011; Liu et al 2019). Taking advantage of the different properties of soil layers, the technique of layering soil has been used in the crop root zone to save agricultural irrigation water and to alleviate soil salinization condition (Wehr et al 2005; Ityel et al 2012)

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