Effects of fertilization on cotton growth and nitrogen use efficiency under salinity stress

Cotton(Gossypium hirsutum) was raised at different salinity levels(0,0.15% and 0.30%) by irrigating with fresh-or sea-water.The effects of fertilization(N,NK,NP and NPK)on plant growth,nitrogen(N) uptake and N use efficiency were studied.The results showed that salinity and fertilization both affected the biomass,agronomic N use efficiency,N bioavailability and nitrogen accumulation of plants,and significant interaction was observed between the two factors.Fertilization could improve N use efficiency and nitrogen accumulation of plants under salinity stress,and significantly promoted the cotton yield.Among the fertilization treatments,N combined with P and K had the best effect.The benefit of fertilization was better under low salinity(0.15%)than under moderate salinity(0.3%).