Evaluation of the yield, nitrogen use efficiency and adaptation in pakchoi cultivars under organic and conventional management systems during two successive seasons

摘要

Two tunnel experiments with 16 pakchoi cultivars were conducted under organic (ORG) and conventional management systems (CON) in fall and winter to investigate the yield, total N uptake, N uptake efficiency (plant aboveground N uptake at harvest per unit plant available N; NUpE), utilization efficiency (plant dry weight per unit plant aboveground N uptake at harvest; NUtE) and specific adaptation of cultivars. Yields under ORG were significantly lower than those under CON, whereas the NUpE in organic pakchoi were significantly higher than those in conventional pakchoi. In winter, a significant interaction between the management system and cultivar for NUtE was observed. In addition, all the traits determined were significantly influenced by the cultivar. Among cultivars, the yield was closely correlated with the NUpE under ORG and CON, except under ORG in fall. The cultivar ranking analysis showed a rank correlation for yield, NUpE and NUtE in winter, while no rank correlation was observed in fall. The rankings of cultivars showed major changes between ORG and CON in fall. In conclusion, the selection of cultivars with high NUpE and direct selection of cultivars under organic agriculture, particularly in fall, will be helpful to improve the yield.