| 摘要: |
| 【目的】探究长期滴灌条件下田块尺度土壤总盐量和盐分离子的时空变化特征。【方法】在新疆库尔勒市包头湖农场的一块独立经营的棉田中（面积为143.52 hm2），根据种植年限（截至2018年，年限为10、14和16 a）划分3块监测区，分别于2003年和2018年，在研究区采用网格法布置了111个样点，监测了土壤总盐及其主要盐分离子量变化。【结果】长期滴灌种植10 a以后，表层土壤总盐量和盐分离子量及其变异系数均显著降低，土壤总盐量和变异系数分别从2003年的18.08 g/kg和116.8%，降至2018年的7.35 g/kg和39.4%。在2003年，种植年限10 a棉田的土壤总盐量及其盐分离子量显著高于种植年限为14 a和16 a，而到2018年差异不显著。滴灌种植条件下，土壤脱盐速率与土壤初始含盐量显著正相关（R2=0.97），3个种植区域，滴灌种植10 a的脱盐速率为4.75 g/（kg·a），种植14 a和16 a的地块脱盐速率分别为：0.59和0.47 g/（kg·a）。且利用克里金插值法，估算了3个在不同初始含盐量水平、不同种植年限的棉田土壤脱盐率分别为85%、53%和51%。【结论】对于重度盐渍化土壤，经过滴灌10 a以后，土壤盐分空间异质性快速降低且趋于均一化，这主要取决于土壤脱盐速率、初始含盐量及种植年限。 |
| 关键词: 土壤盐分；网格采样；表层土壤；种植年限；滴灌 |
| DOI：10.13522/j.cnki.ggps.2020202 |
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| 基金项目: |
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| The Impact of Long-term Drip Irrigation on Spatiotemporal Variation in Salt in the Proximity of Soil Surface in a Cotton Field |
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FAN Weihua, XUAN Junwei, LI Baoguo, SHI Jianchu, LIU Yunhua, SHENG Jiandong
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1. Xinjiang Key Laboratory of Soil and Plant Ecological Process, College of Grass and Environmental Sciences, Xinjiang Agricultural University, Urumqi 830052, China; 2. College of Land Science and Technology, China Agricultural University, Beijing 100193, China
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| Abstract: |
| 【Objective】Soil salinity is modulated by soil water movement, and in this paper we studied the spatiotemporal variation of total salt content and its composition in the proximity of soil surface at a field as impacted by long-term drip irrigation and cotton cultivation.【Method】The measurement was taken from a cotton field with an area of 143.52 ha and under drip irrigation at Baotou Lake Farm in Korla City, Xinjiang. Based on the duration of the cotton cultivation and drip irrigation, we divided the area into three sub-areas that had been cultivated with cotton under drip irrigation for 10 years, 14 years and 16 years, respectively, by the end of 2018. Soils were sampled from 111 sites within a grid network from the subareas in 2003 and 2018 respectively, and the total salt content and the salt composition in each sample were analyzed in laboratory.【Result】The long-term drip irrigation had reduced the total salt content, the content of main ions and their coefficients of variation significantly, with soil salinity and its coefficient of variation reduced from 18.08 g/kg and 116.8% in 2003 to 7.35 g/kg and 39.4% in 2018 respectively. The salinity and its ions contents measured from the samples taken in 2003 in the subarea with 10 years of cotton cultivation was significantly higher than that in the subareas with 14 and 16 years of cultivation, while no significant difference was found between them in the samples taken in 2018. The soil desalination rate was positively correlated with initial salinity content at significant level with R2=0.97, but it decreased as the cultivation duration elapsed. The desalination rate after 10 years, 14 years and 16 years of cultivation was 4.75 g/(kg·a), 0.59 and 0.47 g/(kg·a) respectively. Average desalination rate estimated using the Kriging interpolation was 85%, 53% and 51% for the subareas under cotton cultivation for 10 years, 14 years and 16 years respectively.【Conclusion】 For heavily saline soil, 10 years of drip irrigation was sufficient to reduce the spatial heterogeneity of its salinity rapidly due to the desalination by leaching and cotton uptake combined. |
| Key words: soil salinity; archive samples; topsoil; cultivation duration; drip irrigation |
