Nitrogen application improved peanut yield and nitrogen use efficiency by optimizing root morphology and distribution under drought stress
|Hong Ding1, Zhimeng Zhang1, Guanchu Zhang1, Yang Xu1, Qing Guo1, Feifei Qin1, and Liangxiang Dai1|
|Drought stress and nutrient deficiency are two main factors that restrict the growth and yield of peanut (Arachis hypogaea L.) in arid and semi-arid regions. However, the effects of N fertilizer on root growth and pod yield of peanut under different water conditions are unclear. The growth, root morphology, and pod yield of peanut were studied under different water and N combinations. Two soil water treatments were tested: Well-watered (WW, 80%-85% field capacity) and droughtstress conditions (DS, 55%-60% field capacity). Three N treatments were tested: no N application (NN), moderate N (MN, 90 kg ha-1), and high N (HN,180 kg ha-1). Results showed that pod yield of peanut was limited by drought and N deficiency. Compared with NN, peanut shoot DM and pod yield were improved by MN under DS, with an averageincrease range of pod yield of 16.2% in the 2 yr. The annual average root length density (RLD) in the deeper soil layer (40-100 cm) was 5.5% higher under DS-MN than DS-NN treatment. The N use efficiency (NUE) was 12.3% higher under WW than DS treatment, and the NUE of MN was significantly higher than that of HN under different water treatments.Root lengths in 40-60 and 60-80 cm soil layers were also positively correlated with pod yield (r = 0.66** and 0.47**, respectively) and NUE (r = 0.60* and 0.85**, respectively). In this study, root growth in deeper soil was improved by MN application under DS, thus increasing yield and NUE of DS conditions.|
|Keywords: Drought stress, nitrogen use efficiency, peanut, root architecture, water-nitrogen interaction.|
|1Shandong Peanut Research Institute, Qingdao 266100, China.|
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