Effect of nitrogen application on dry matter and nitrogen remobilization of spring barley under water deficit conditions

In order to evaluate the effect of inorganic nitrogen on dry matter and nitrogen remobilization in spring barley under water deficit conditions, a factorial experiment based on completely randomized design with three replications was conducted in the greenhouse condition in 2012. Irrigation schedules imposed in pots at three levels (35%, 60% and 85% field capacity) and the nitrogen fertilizer applied at three rates (40, 80 and 120 kg ha-1) on the EBYTW-11 spring barley genotype. The results showed that the DM remobilization from different parts of plant (stem, flag leaf, other leaves and peduncle) to the grain was affected by water deficit and nitrogen levels, so that the highest amount of dry matter remobilization belonged to other leaves under mild water stress (FC 60%) with 40 kg ha-1 nitrogen. Also, the efficiency of dry matter transferring from the foliar to the grain was influenced by nitrogen application and water deficit. The contribution of DM remobilization from stem and peduncle was significantly affected by water deficit and nitrogen. The maximum efficiency of dry matter allocation to grain belonged to the flag leaf under severe stress with 40 kg ha-1 nitrogen. It seems that under severe stress, the most amount of dry matter is transmitted to the spikes because of earliness, accelerated aging and loss of lower leaves. The results showed that when the plant is exposed to nitrogen deficiency in the soil, nitrogen remobilization efficiency from vegetative organs would be higher.