Response characteristics of saline soil evaporation in Yellow River Delta under different salinity levels
YU Chao1, SUN Chitao1*, ZHANG Qian1, SUN Yuxia1, ZHU Ziguo2, LI Bo2, LYU Pengchao3, YU Shaoli3
1. College of Water Conservancy and Civil Engineering, Shandong Agricultural University, Taian, Shandong 271000, China; 2. Shandong Academy of Grape, Jinan, Shandong 250000, China; 3. Weihai Agricultural and Rural Affairs Service Center, Weihai, Shandong 264200, China; 4. Haiyang Agricultural Technology Extension Center, Haiyang, Shandong 265100, China
Abstract：In order to explore the response characteristics of soil evaporation in the Yellow River Delta under different salinity levels, saline water with salinity of 5, 10, 30, 50, 70, and 90 g/L were utilized to irrigate the 0-40 cm soil(which were labeled T1—T6 in turn)in the Yellow River Delta. And soil moisture treatment with different salinity gradient is marked as treatment T1—T6 in turn. The soil water content, electrical conductivity, evaporation intensity and cumulative evaporation were measured during the experimental period. The results showed that the surface soil moisture and electrical conductivity increased gradually with the increase of soil salt content during evaporation process. At the end of evaporation, the average water content of soil surface layer treated with T1—T6 was 80.0%-95.8% lower than that at the beginning of the experiment. The soil electrical conductivity of the surface layer increased by 135%-330%, and the electrical conductivity increase of soil surface during the early evaporation stage was significantly higher than that during the later stage. The distribution of soil moisture and electrical conductivity were significantly effect by soil salt content. At the end of evaporation, the soil moisture content of 0-2 cm surface layer of T1—T6 treatments were 8.3%-30.5% lower than that of 3-6 cm, while the electrical conductivity of 0-2 cm for T1—T6 treatments were 82%-196% higher than that of 3-6 cm. The difference between surface and deep layer for soil salt content gradually increased with the increase of soil salt content. During the evaporation process, the average soil evaporation intensity and cumulative evaporation decreased with the increase of soil salt content, and the average evaporation intensity of T1—T6 treatment were 3.5×10-4, 3.5×10-4, 3.4×10-4, 3.2×10-4, 3.0×10-4 and 2.7×10-4 mm/d, and the cumulative evaporation were 26.13, 26.20, 25.50, 24.26, 22.50 and 20.58 mm respectively. The average evaporation intensity and accumulated evaporation of each treatment in the early stage of evaporation were higher than those in the late stage of evaporation. The inhibitory action of soil salt content on soil evaporation was mainly in the early stage of evaporation. The results showed that soil salinity could affect the distribution of soil moisture and electrical conductivity, as well as soil evaporation intensity and cumulative evaporation.
