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| DOI：10.13522/j.cnki.ggps.2025346 |
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| Effects of water-nitrogen-salt coupling on soil water-salt distribution and cotton yield in oasis cotton fields |
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Liu Keshun, Li Wenhao, Lyu Tingbo, Gao Shuanglong, He Jinyin
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1. College of Water Conservancy & Architectural Engineering, Shihezi University, Shihezi 832000, China;
2. Key Laboratory of Modern Water-saving Irrigation of Xinjiang Production & Construction Crop, Shihezi 832000, China;
3. Key Laboratory of Northwest Oasis Water-saving Agriculture, Ministry of Agriculture and Rural Affairs, Shihezi 832000, China
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| Abstract: |
| 【Objective】Soil salinization and water scarcity are the main abiotic stresses affecting cotton production in Xinjiang oases. Optimal regulation of soil water, salt and nitrogen can alleviate these adverse effects. This paper experimentally investigated the effects of water–nitrogen–salt coupling on the spatiotemporal dynamics of soil water and salt, as well as growth and yield formation of cotton in a saline soil.【Method】The experiment was conducted in pots with drip irrigation. It included two irrigation treatments: 4 500 m3/hm2 (W1) and 3 600 m3/hm2 (W2), three nitrogen treatments: 200 kg/hm2 (N1) 300 kg/ hm2 (N2), 400 kg/ hm2 (N3), and three soil salinity levels: 2 g/kg (S1), 4 g/kg (S2), and 6 g/kg (S3). A partial least squares path model (PLS-PM) was used to identify the key pathways that control cotton yield formation.【Result】Soil water was predominantly distributed in the 20-40 cm soil layer, where the water content was 25.35%-60.09% higher than that in the topsoil (0-20 cm). As the crop grew, topsoil salinity initially decreased and then increased. Relative to its initial value, the average topsoil salt content decreased by 0.29 g/kg in the early growth stage and increased by 0.35 g/kg in the late stage. Increasing irrigation volume and nitrogen application effectively reduced soil salinity. Elevated soil salinity significantly inhibited cotton yield formation. The optimal irrigation and fertilization combinations for maximum yield under S1, S2 and S3 were W1N2, W1N2 and W1N3, respectively. Correlation analysis revealed that cotton yield was positively correlated with growth indicators and negatively correlated with soil salinity. PLS-PM analysis showed that soil salinity was the dominant limiting factor for cotton growth; it indirectly regulated cotton yield by altering spatiotemporal distribution of soil water and salt.【Conclusion】The optimal irrigation and nitrogen fertilization for S2 and S3 were 4 500 m3/hm2 and 300 kg/hm2, and 4 500 m3/hm2 and more than 300 kg/hm2, respectively. This irrigation and fertilization strategy can save water, improve nutrient use efficiency and stabilize cotton yield in saline oasis in the study region. |
| Key words: drip irrigation under film; salinized cotton field; PLS-PM; water-nitrogen-salt coupling; yield formation |
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