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| DOI：10.13522/j.cnki.ggps.2019200 |
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| The Effects of Soil Amendment with Different Materials on Soil Salt Distribution and Its Ion Composition under Brackish-water Drip Irrigation |
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ZHENG Fule, YAO Rongjiang, YANG Jingsong, WANG Xiangping, CHENG Qiang, LI Hongqiang
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1.State Key Laboratory of Soil and Sustainable Agriculture/Institute of Soil Science, Chinese Academy of Sciences,Nanjing 210008, China；2. University of Chinese Academy of Sciences, Beijing 100049, China; 3. Dongtai Institute of Tidal Flat Research, Nanjing Branch of Chinese Academy of Sciences, Dongtai 224200, China; 4. Centre of Agricultural and AnimalHusbandry Technology Extension of Hanggin Rear Banner of Inner Mongolia, Shaanba 015400, China
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| Abstract: |
| 【Background】Inferior irrigation and drainage management has resulted in soil salinization undermining agricultural production and water resources use efficiency in Hetao Irrigation District. Combing soil amendment and brackish groundwater irrigation could control soil salinity and has been widely studied. However, most existing research has focused on its impact on total soil salt and crop yield, while the associated change in ion composition has been overlooked.【Objective】The purpose of this paper is to study the influence of drip irrigation with brackish groundwater, along with different soil amendments, on salt dynamics and its ion composition in soil.【Method】The experiment was conducted in a moderate-heavy saline field in Hetao Irrigation District with sunflower as the model plant. It consisted of four treatments: ①Conventional flooding irrigation without soil amendment. ②Brackish water drip irrigation without soil amendment. ③Brackish water drip irrigation with soil amended by biochar. ④Brackish water drip irrigation with soil amended by gypsum. In each treatment, we measured salt content and its ion composition.【Result】The average soil desalination under brackish water drip irrigation was 13.46%, up 7.14% against the conventional irrigation. Drip irrigation did not lead to a noticeable salt accumulation, but compared with conventional irritation, it increased Na+ and Cl- content by 91.13% and 47.21% respectively, giving rise to sodication and salt accumulation in the 20~40 cm soil. Brackish water drip irrigation coupled with soil amendment by biochar or gypsum enhanced soil desalination and reduced soil sodication, especially the gypsum amendment which increased soil desalination by 46.30%. Compared with other treatments, brackish water drip irrigation coupled with biochar amendment increased salt content and proportion of K+, Mg2+ and SO42- in the topsoil during the growth season of the sunflower. On the contrary, brackish water drip irrigation with gypsum amendment reduced the proportion of Na+, Cl- and Mg2+ at the expense of Ca2+ and SO42- in the topsoil.【Conclusion】Brackish water irrigation coupled with soil amendment not only affected soil salinity but also alerted its ion composition. Combining brackish water drip irrigation with soil amendment with biochar and gypsum improved soil desalination and ameliorate sodium accumulation – a typical phenomenon accompanied with brackish water irrigation. Our results have important implications for improving saline-alkali soil management and water use efficiency in irrigated cropping systems in arid areas like Hetao Irrigation District. |
| Key words: brackish water drip irrigation; Hetao Irrigation District; soil salinity; ionic composition; biochar; gypsum |
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