Effects Of Soil Salinity On Growth And Nutrition Absorption Of Cotton Under Surface And Subsurface Drip Irrigation

Soil salinization is an important restraint factor for agriculture development and threatens the safety of grain production of the world. The under-film drip irrigation has gained widespread popularity as an efficient and economically viable irrigation method for increasing water use efficiency and reducing the adverse effects of salinity on plant growth and yield. A field experiment was conducted under the saline soil in order to evaluate the relationship among distributions of soil salinity, water content and cotton root and those effects on growth and yield of crop. Major finds list as follows:1. Soil water content increased with increased soil salinity in both surface and subsurface drip irrigation. Soil water mainly distribute at 20-70 cm in subsurface drip irrigation, but at 0-50 cm in surface drip irrigation. The unsalted zone was found at 0-20 cm in surface drip irrigation and 30-50 cm for subsurface drip irrigation. Soil salt was leached to deeper layer in subsurface drip irrigation than that in surface drip irrigation.2. Distributions of nitrate were influenced significantly by soil salinity. The more soil salinity the more leached nitrite is. There are no significant differences for concentration of available phosphorus in soil among different soil salinity treatments, but higher concentration of available phosphorus was found in deep soil layer in subsurface drip irrigation than that in surface drip irrigation.3. N and P accumulation of cotton decreased with increased of soil salinity. K+ concentration increased with increased of soil salinity. Slat ions (Na+, Cl-) concentration of cotton increased significantly with soil salinity increasing during growth season and mainly accumulated in stems and leaves of cotton.4. With soil salinity increasing, root weight, length and surface area was reduced, but increased for root diameter. Root length, surface area and volume mainly distributed at top 0-20 cm soil depth under surface drip irrigation, but at deep soil layer under subsurface drip irrigation.5. Dry matter weight of cotton decreased significantly with increasing of soil salinity level, but there no significant differences were found between surface and subsurface drip irrigation. Soil salinity reduced the number of bolls significantly and affected seed cotton yield. The seed cotton yield was slight higher in subsurface drip irrigation than that in surface drip irrigation.