排盐暗管间距对河套灌区重度盐碱土盐碱特征与肥力的影响

为合理设计暗管排盐参数,提高河套灌区盐碱土的改良效果,通过布设田间试验,在轮灌方式下,对比分析了10、20、30m暗管间距条件下土壤盐离子、碱化程度和肥力指标特征,研究了暗管间距对河套灌区重度盐碱土脱盐治碱效果的影响。结果表明:(1)10、20、30 m间距处理0～10 cm土层淋洗前土壤含盐量分别为17.22、17.74和17.17 g/kg,秋浇前分别为10.78、11.56、11.95 g/kg,不同暗管间距处理的土壤脱盐率表现为:10 m20 m30 m。(2)灌水后各处理土壤碱化指标均表现出先增大后减小的变化趋势,10、20、30 m间距处理0～10 cm土层土壤p H在秋浇前较第3次淋洗后分别降低了4.47%、3.72%和2.96%,说明小间距的暗管布设更具有缓解土壤碱化程度的潜力。(3)暗管排水过程中会使土壤养分大量流失,各间距处理的流失量依次为10 m20 m 30 m。

Effects of Underground Drainage Pipe Spacing on Salt and Alkali Characteristics and Fertility of Heavy Saline Soil in Hetao Irrigation Area

In order to design the parameters of salt drainage by underground pipes reasonably and improve the improvement effect of saline alkali soil in Hetao irrigation area. In this paper, based on the field experiment and the method of rotation irrigation, the soil salt ion, alkalization degree and fertility index under the condition of 10m, 20m and 30m underground pipe spacing were compared, and the effect of underground pipe spacing on the desalination and alkali treatment effect of heavy saline alkali soil in Hetao irrigation area was studied and analyzed. The results showed that: (1) the leaching efficiency of cations in different treatments was Na+ > Ca2+ > Mg2+ > K+, and the decreasing range of anions was Cl- > SO42- > HCO3-. The soil desalting efficiency of the treatment with different underground pipe spacing was as follows: 10m > 20m > 30m, and the salt leaching efficiency of the treatment with 10m spacing was higher than that of the treatment with 20m and 30m. (2) The soil alkalinity and exchangeable content of Na+ of each treatment showed the characteristics of increasing in the early stage and decreasing in the later stage after irrigation. The soil alkalinity of 10m interval was larger than 20m and 30m, but it still had the potential to alleviate the soil alkalinity. (3) In the process of drainage with underground pipes, soil nutrients would be largely lost, and the loss amount of each spacing treatment was 10m > 20m > 30m in turn. The influence of the distance between the underground pipes on the soil desalination and alkali treatment is very great. The area with serious salinization can adopt the way of small distance underground pipes to improve the soil salinization by improving the efficiency of soil desalination. This study provides an important theoretical basis for improving the land production capacity of Hetao Irrigation Area and the application of the technology of underground pipes drainage and salt drainage.