滨海农区微咸水-淡水交替灌溉对土壤EC和入渗的影响

摘要

Pot experiments with corn and coastal agricultural soils were conducted in a greenhouse without exposition to rainfall. Salinity of 0.2 g/L tap water and NaCl solution were used to set up three salinity levels (i.e., 1, 3, and 5 g/L) of saline water. Three types of alternative irrigation modes (“brackish water-fresh water-fresh water”, “fresh water -brackish water-fresh water”, and “fresh water-fresh water-brackish water”) were used to study the effect of water salinity and irrigation mode on soil electrical conductivity (EC) value and inifltration. The result showed that salinity had a signiifcant inlfuence on soil EC value, and EC value increased with the increase of salinity and soil depth. Soil EC value ranked in the order of “brackish water-fresh water-fresh water”<“fresh water-brackish water-fresh water”<“fresh water-fresh water-brackish water” in terms of alternative irrigation mode. Accumulative soil inifltration amount and stable inifltration rate also increased with the increase of salinity. Soil stable inifltration rate increased with enhanced salinity levels, whereas it was similar under different types of alternative irrigation modes. These results provide scientiifc basis for the security of brackish water use and agricultural sustainable development in coastal agriculture.%以玉米为载体，取滨海农区土壤开展温室避雨盆栽试验，采用矿化度为0.2 g/L的自来水配置NaCl溶液，设置了3种（NaCl，分析纯）矿化度水平（1 g/L，3 g/L，5 g/L）和3种微咸水-淡水交替灌溉方式（“咸淡淡”，“淡咸淡”，“淡淡咸”），研究灌水矿化度和微咸水-淡水交替灌溉方式对试验土壤EC及入渗的影响。结果表明：灌水矿化度对土壤EC值有显著影响，EC值随着矿化度和土层深度的增加而增加；同一土层深度、相同矿化度、不同微咸水-淡水交替灌溉方式，土壤EC值表现为“咸淡淡”<“淡咸淡”<“淡淡咸”。同时土壤的累积入渗量和稳定入渗率均有随矿化度增加而增大的特性；灌水矿化度差异显著影响土壤稳定入渗率，土壤稳定入渗率随灌水矿化度增加而增大；而同一矿化度、不同微咸水-淡水交替灌溉方式处理下，土壤的稳定入渗率差异不大。本实验研究成果可为滨海农区微咸水安全利用与农业可持续发展提供科学依据。