Abstract:
In order to study the effect of different groundwater depth on soil water and salt transport and its changing characteristics in takyric solonetz soil, the salt content, water content and salinity of the soil under six groundwater depths of 0.8,1.0,1.2,1.5,1.8 and 2.0 m are monitored in takyric solonetz land at the farmland of Xidatan in Ningxia, China. The results show that there is an exponential relationship between soil total salt and groundwater depth, and there is a significant linear positive correlation between soil total salt and groundwater salinity. The change of total salinity and alkalinity is 0.8 m >1.0 m >1.5m >1.8m >2.0 m; 1.5 m ground water depth is the turning point of soil water and salt change. The total salt and water content of each soil layer are higher at 0.8~1.2 m ground water depth. The variation of soil water and salt is the most serious in the soil with the groundwater depth of 1.5~1.8 m. Oil sunflower grows in 1.5~2.0 m depth of ground water suitably. The emergence rate, survival rate, plant height, stem diameter, diameter and yield of oil sunflower in 0.8, 1.0 and 1.2 m of groundwater table are significantly lower than those in 1.5, 1.8 and 2.0 m of groundwater table. There are no significant differences in soil water content, total salinity and alkalinity, emergence rate, survival rate, plant height, stem diameter, disc diameter and yield of oil sunflower at depths of 1.5, 1.8 and 2.0 m. These results will provide a technical support for salt-water management of the takyric solonetz farmlands, and have an important scientific value for environmental protection and agricultural irrigation development in arid areas.