Abstract:

The sediment concentration affects the soil mechanical composition, nutrients, moisture content, ion exchange and plant growth, but the current research on the impact of soil sediment concentration on plant growth are rare. Stevia transplanting seedlings were used in the present study to explore the effect of different sand/soil ratio (clay with no sand; sand/soil=20%, 40%, 60%, 80%; pure-sand) on Stevia growth. Results showed that Stevia was the ideal sand environment economic crops and had a good adaptability, good shape and high yield in sandy soil environment; With the increasing of soil sediment concentration, soil moisture reduced gradually; stevia plant height, leaf and stem biomass increased first after reduction; root length gradually became longer, but base diameter became smaller gradually, root biomass reduced gradually; Therefore, the effect of soil sediment concentration on the growth of stevia can be summarized as "low to promote high suppression" effect, namely, there was an optimum soil sediment concentration range making Stevia obtain maximum yield, when soil sediment concentration was 20%-40% (that is, the grains of sand content is 68%-77%) can significantly increase yield of Stevia dry leaves by 5.7%.

Key words: Stevia rebaudiana, photosynthesis, biomass allocation, sand/soil content, root-shoot ratio