| 引用本文: | 化骞寂,冯绍元,葛 洲,等.河套灌区典型区周年内耕层土壤盐分时空变异研究[J].灌溉排水学报,2020,39(8):26-34. |
| ,et al.河套灌区典型区周年内耕层土壤盐分时空变异研究[J].灌溉排水学报,2020,39(8):26-34. |
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| 摘要: |
| 【目的】研究河套灌区典型区耕层土壤盐分在周年内的时空变异规律，分析其盐碱化风险。【方法】利用经典统计分析与地统计分析相结合的方法分析研究区周年内（2018年秋浇前到2019年秋浇前）耕层土壤盐分的空间变异性，利用指示Kriging插值法绘制出土壤盐分的概率分布图，分析其分布规律。【结果】①各时期土壤含盐量0~10 cm＞10~20 cm＞20~40 cm；耕地各土层在夏灌期处于积盐状态，荒地在三水前变化很小，之后迅速积盐，耕地和荒地各土层自下而上积盐速度逐渐增大，荒地积盐速度大于耕地。②各时期0~40 cm土壤盐分半方差模型均可以用球状模型拟合，变程在1 104~1 994 m之间，属于中等空间自相关性，秋浇前土壤盐分空间结构性略好于其他时期。③同一年内土壤盐碱化高风险区面积逐渐增大。【结论】各时期土壤盐分呈表聚型，夏灌期均处于积盐状态，盐荒地旱排盐效果显著；研究区一水前到五水前土壤盐分空间结构性变化不大；同年各时期盐碱化分布格局类似，但积盐程度和盐碱化面积都随时间逐渐增加，节水灌溉条件下秋浇压盐更为重要。 |
| 关键词: 土壤盐分；河套灌区；盐碱化风险分析；指示Kriging |
| DOI：10.13522/j.cnki.ggps.2020012 |
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| Intra-annual Spatiotemporal Variation in Salt Content in the Plough Layer in Hetao Irrigation District |
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HUA Qianji, FENG Shaoyuan, GE Zhou, XU Ying
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College of Hydraulic Science and Engineering, Yangzhou University, Yangzhou 225009, China
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| Abstract: |
| 【Background】Soil salinization is a main abiotic factor causing land degradation threatening agricultural production; it could make agroecological systems vulnerable, especially in arid and semi-arid regions. Hetao irrigation district is a typical salt-affected inland area in north China, characterized by shallow groundwater, scarce precipitation and intensive evaporation. Understanding spatiotemporal variation of soil salinity in the district is essential to improving its water use efficiency and salinization management.【Objective】This paper aims to study the intra-annual spatiotemporal variation in salt content in the plough layer and assess its risk in resulting in salinization across the district.【Method】The study was based on field data measured from autumn 2018 to autumn 2019, and we analyzed them using geostatistics and descriptive statistics. The probability distribution map of the salt content was obtained by the indicator Kriging interpolation. 【Result】①Salt content in different soil layers was ranked in the order of 0~10 cm >10~20 cm >20~40 cm, irrespective of sampling date and time. Salt accumulated in soil during the summer irrigation. Prior to the third irrigation, salt content in natural soil did not show noticeable change but accumulated rapidly since then. A rapid salt accumulation in 20~40 cm and 0~10 cm soil was found in both cultivated and natural lands, although the accumulation in the latter was faster than in the former. Regardless of sampling date and time, salt content in 0~10 cm soil varied more erratically than in 10~20 cm and 20~40 cm soils. The coefficient of variation of the salt content was greater in natural land than in cultivated land. ②Semi-variance model of the salt content in 0~40 cm soil sampled at any date and time can be fitted to the spherical model with the range in 1 104~1 994 m. Salt content showed moderate spatial autocorrelation, and its spatial structure prior to the autumn irrigation was slightly stronger than that in other seasons. ③Areas with high-risk of soil salinization increased in 2019 with areas containing salt > 1 g/kg up from 26% to 90% against that in 2018. Salt-affected areas increased fast from the first irrigation to the second irrigation and from the third irrigation to the fifth irrigation.【Conclusion】Salt accumulated in soil surface during the summer irrigation, and dry-drainage was effective to control soil salinity. The spatial distribution of salt did not show noticeable change from the first irrigation to the fifth irrigation, but was similar at different sampling date and time. Both salt accumulation in soil and salinized areas had increased during this period, indicating the importance of desalinization using water-saving irrigation in the autumn. |
| Key words: soil salinity; Hetao irrigation district; analysis of salinization risk; indicator Kriging |
