Effects of Salt Ions Transport on Different Levels of Secondary Salinization Soil under Greenhouse Irrigation

Abstract:

The salt ions distribution at different levels of secondary salinization of greenhouse soil under the same irrigation was investigated through soil columns in lab. The results were as follows: Ca2+ and NO-3 were showed “double peaks” feature on the distribution profile in the irrigation of 5~15 d. With the increased level of secondary salinization, Ca2+ and NO-3 were leached more slowly while the return of salt time later. Migration of groundwater on the K + had no significant effect. The K+ ions showed a “single peak” feature on the distribution profile after irrigation. The SO2-4 was difficult to be leached out of topsoil under all the degree of secondary salinzation. Factors from the environmental perspective, Ca2+ in the soil surface and bottom were prominent with a good coupling effect of air temperature, soil moisture content and soil salt content, and both of the Ca2+ transport had a synergistic effect. K+ transport in 0~20cm soil layers affected mainly by water, while the 30~50cm soil layers mainly influenced by temperature, the time from the irrigation point of view, in 5~15 d after irrigation affected by temperature, but after 20 d affected mainly by water, while the 30~50cm soil layer mainly influenced by temperature, the time from the irrigation point of view, in 5~15 d after irrigation affected by temperature, but 20 d after irrigation affected mainly by water. Whether from the soil or the time, NO-3 and SO2-4 transport was influenced mainly by water.