Abstract:

 To clarify the effect of nitrogen (N) application on peanut yield, N uptake and N use efficiency under water stress at later growth stage (pod filling stage), peanut cv Huayu25 was planted in soil column which was pro? tected from rainfall by a mobile shelter. Soil water condition at pod filling stage and N application rate were used as 2 factors for experimental design. The soil water condition was performed in 3 levels: well-watered conditions (W0), mild drought (W1) and medium drought (W2) (the corresponding soil water contents were respectively 70%-75%, 55%-60% and 45%-50% of field moisture capacity). N application rates were set in 5 levels: 0 (N0), 45 kg·hm-2 (N1), 90 kg·hm-2 (N2), 135 kg·hm-2 (N3) and 180 kg·hm-2 (N4). Result showed that peanut economic yield, plant
biomass, and N accumulation in seed and total plant were the highest under W1N2 treatment. Compared with other N application rates, yield and harvest index were increased in N2 treatment under the same water treatment. The Ndff (percentage of N derived from15N fertilizer) in peanut organs were significantly increased with the increasing of N application rate, while the increasing range was different. The N use efficiency of peanut were increased initially and then decreased with the N application under well-water condition and mild drought stress. The N use efficiency decreased with the increase of N application under moderate drought stress. It was concluded that peanut dry matter and N accumulation under W1N2 treatment were optimal, and N distribution in reproductive organs and N use effi? ciency were the highest. The effect of water deficiency at pod filling stage on peanut yield could be compensated by
applying 90 kg·hm-2 nitrogen fertilizer (N2).

Key words:  , peanut；pod filling stage；drought stress；nitrogen accumulation；yield；nitrogen use efficiency