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| DOI：10.13522/j.cnki.ggps.2022576 |
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| The Impact of Ion Composition in Saline Water on Soil Salinity, Salt Distribution, and Crop Growth under Mulched Drip Irrigation |
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ZHANG Tonggang, HU Xinglu, LUO Min, WANG Chun,
YAN Sihui, CHENG Yu, LIANG Qing, FENG Hao, ZHANG Tibin
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1. College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling 712100, China;
2. Institute of Soil and Water Conservation, Northwest A&F University, Yangling 712100, China;
3. Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, China
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| Abstract: |
| 【Objective】 Saline water has been used as a supplementary irrigation resource in most countries to sustain agricultural production. The purpose of this paper is to study the influence of ionic composition in saline water on soil properties and growth of corn under mulched drip irrigation.【Method】 The field experiment was conducted from April to September 2021 in the Hetao Irrigation District (HID) in Inner Mongolia. The saline water was created by adding different chloride salts: NaCl (T1), KCl (T2), CaCl2 (T3) and MgCl2 (T4) to fresh water. Irrigation with fresh underground water served as the control (CK). During each treatment, change in soil structure, transport of water and salt in soil, and crop growth were measured.【Result】① Compared to CK, T1 significantly increased the number of small pores in the top 0~20 cm soil layer. This had a detrimental impact on soil structure but increased its water storage, particularly during the jointing stage. Compared to CK, T3 and T4 reduced the small porosity by 147.73% and 132.01%, respectively, but increased permeability of the soil. ② Compared to CK, all treatments increased the concentrations of Na+, K+, Ca2+ and Mg2+ in the 0~60 cm soil layer. Except T1, other treatments increased the concentrations of K+, Ca2+, and Mg2+, compared to CK. T1 resulted in salt accumulation in the soil surface, while other treatments did not show noticeable impact on ion composition. It was found that T3 and T4 moved the salt out the zone controlled by the mulch in the lateral direction, particularly T4. The electrical conductivity (EC) of the saturated extract from the root zone soil was influenced by the EC of irrigation water and varied in the range of 3~4 dS/m. ③ Na+ and K+ contents were the lowest and highest in the aboveground part, respectively. Na+, K+, and Cl- contents were higher in leaves than in stems, while Ca2+ and Mg2+ contents were higher in stem than in leaves. Increasing irrigation amount enhanced crop yield only in some treatments. Among all treatments, T4 gave the highest corn seed yield, 17.33% more than CK.【Conclusion】Irrigation with saline water containing high Na+ increased the small porosity of the topsoil, affecting soil water infiltration. In contrast, increasing K+, Ca2+, and Mg2+ contents reduced small porosity, promoting salt leaching due to the increased soil permeability. Keeping concentration of K+, Ca2+ and Mg2+ at appropriate levels under saline water irrigation is beneficial to increasing dry matter accumulation and the final yield, as it offsets the negative effects of excessive Na+. These findings provide guidance for safe utilization of saline water for irrigation in HID. |
| Key words: porosity; water and salt distribution; cation; corn growth |
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