Effect Of Nitrogen Supply On Salt Absorption Capacity Of Suaeda Salsa (Linn.) Pall Under Drip Irrigation

In northern part of Xinjiang province, one3-year field experiment was conducted inresidual solonchaksoils under drip irrigation to study the effect of nitrogen supply on salt absorption capacity of suaeda salsa(Linn.) Pall, investigate whether suaeda salsa could decrease soil salinity efficiently and if it could,calculate the bio-remediation term, evaluate effects of suaeda salsa on soil improvement by shift of soil salt,nutrient and soil water content. The main results are as follows:(1) Soil salt concentration decreased with suaeda salsa growth in0-100cm soil under drip irrigation.Theelectricity conductivity (EC), total dissolved salt (TDS) concentration and Na+concentration decreasedsignificantly. With same nitrogen application amount, salt content decreased remarkablely as soil depthincreased in20-80cm soil, while salt content decrement of0-20cm soil layer was lower than that of20-40cm soil.(2) Nitrogen supply enhanced ash accumulation in shoot of suaeda salsa and efficiency of soilremendiation, which greatest value appeared when nitrogen supply amount was300kg/hm2. The greatestshoot ash content were respectively2617.69kg/hm2and1066.86kg/hm2in2012and2013. Efficiency ofsoil remendiation was948.86kg/hm2.y and318.57kg/hm2.y in2012and2013.When the highestremediation efficiency is948.86kg/hm2.y, about157years is required to decrease salt content from20g/kgto10g/kg in1m soil or110years from10g/kg to3g/kg.(3) Plant suaeda salsa could decreased salt content efficiently, but water from irrigation and rain was themost important factor on soil desalination. In2012and2013, net salt amounts of suaeda salsa absorpedfrom soil were respectively account for1.61%and0.19%of soil total output, and salt content leached byirrigation and rain account for98.39%and99.81%, respectively.(4) Salt content decreased significantly with continuous suaeda salsa growth. The soil organic matter(SOM), NH+4-N, NO-3-Nand available potassium decreased in0-40cm, while soil available phosphorusincreased. In0-20cm soil, NO-3-N concentration increased as nitrogen application amount increased, but itdecreased with nitrogen application amount increased in20-40cm soil. The increment of availablephosphorus in0-20cm soil layer was greater than that in20-40cm soil.Conclusion: Under drip irrigation, nitrogen supply could improve suaeda salsa residual solonchakefficiently,but it is required a long period to achieve success, and it is less efficient to decrease soil salinitythan by water elution.