一.土壤次生盐渍化是灌溉农业的巨大威胁黄河下游华北平原地区,地势平坦,土地辽闊,农民几千年来累积了丰富的耕作經驗,农业生产有巨大潜力,是我国农业生产的重要基地。但过去由于洪水为患,春旱秋涝,限制了农业生产的发展,以致生产水 I. Secondary salinization of soil is a huge threat to irrigated agriculture In North China Plain, the lower reaches of the Yellow River, the terrain is flat and the land is vast. Farmers have accumulated rich farming experience for thousands of years and have great potential for agricultural production. Important base. However, in the past, due to flooding, the drought and flood in autumn restricted the development of agricultural production, resulting in the production of water