Saline Soil Management and Improvement Protection Strategies Based on Sustainable Agricultural Development Goals

The shortage of water resources, the serious harm of soil salinization and the large loss of nitrogen caused by excessive application of nitrogen fertilizer are the main factors restricting the sustainable development of agriculture in irrigation areas. Based on this factor, saline irrigation area needs to find a soil improvement method that can keep water and restrain salt, increase fertilizer and increase production under the condition of reducing the amount of nitrogen fertilizer application, which is of great practical significance for promoting the development of saline soil improvement technology and high and stable grain yield. In this paper, the physical and chemical properties, temporal and spatial dynamic distribution of water, fertilizer and salt content, sunflower yield and water and nitrogen use efficiency of saline soil in Hetao irrigation area were studied by means of field experiment and numerical analysis, and the improvement mechanism and water, fertilizer and salt regulation effects of different soil amendments on saline soil in irrigation area were revealed. The results showed that the biochar treatment group significantly reduced soil pH and conductivity, effectively inhibited salt accumulation in the soil, and increased soil organic matter content and nutrient content such as total nitrogen, available phosphorus and available potassium. The porous structure of biochar enhances the soil’s water retention capacity and reduces soil water evaporation. The combination of carbon and nitrogen application treatment not only reduced nitrogen loss but also prevented salt from moving to the soil surface, further optimizing the soil environment. In terms of crop growth and yield, the group treated with carbon nitrogen combined application showed the best growth performance of sunflowers, with rapid plant height growth, lush leaves, and the highest leaf area index. The overall growth momentum was stronger than other treatment groups.