Effects of Salt Water Drip Irrigation on Jujube Roots Soil Available Nitrogen Distribution: A Security Assurance Perspective

Field experiment was used in this research to study influences brought by salt water with different degrees of mineralization to distribution characteristics of soil available nitrogen and nitrate nitrogen in red jujube root zones when the salt water drip irrigation was carried out to jujubes. It is shown in the results that the distribution content of soil available nitrogen in jujube tree root zones tended to gradually decrease from top to bottom in the soil profile at different growth stages. The soil available nitrogen contents at different growth stages exceeded initial values. The mineralization degrees of salt water which influenced the available nitrogen were successively 3 g/L＞4 g/L＞2 g/L＞CK, wherein the salt water with mineralization degree of 3g/L brought largest influences to transformation and utilization of available nitrogen in jujube tree root zones; with regard to different growth stages, the available nitrogen content was high in the soil layer with depth of 0-20 cm in the jujube root zone, and the content was small in the soil layer with depth o 30-50 cm; during drip irrigation with the mineralization degree of over 3g/L, the nitrate nitrogen content in soil layers of the jujube tree root zone exceeded the content under fresh water irrigation treatment as a whole.