Effects of water and nitrogen coupling on growth and yield of Carthamus tinctorius L. under mulch drip irrigation

【Objective】 To study the effects of water and nitrogen coupling on the growth, dry matter accumulation and yield of Carthamus tinctorius L.. 【Methods】 The split area test design was adopted, with the irrigation volume as the main area. Before sowing, basic fertilizer diammonium phosphate (64% of total nutrients, N-P₂O₅=18-46) 150 kg/hm², potassium oxide (30%) 75 kg/hm² were applied and two factors of irrigation water (W) and nitrogen application rate (N), three irrigation water levels were set: W₁: 1,200 m³/hm² (low irrigation rate), W₂: 1,500 m³/hm² (middle irrigation rate) and W₃: 1,800 m³/hm² (high irrigation rate), three nitrogen application levels: N₀: no nitrogen application (contrast), N₁:300 kg/hm² (traditional nitrogen application rate) and N₂: 600 kg/hm² (high nitrogen application rate). During the test, the agronomic characters, dry matter accumulation and yield of Carthamus tinctorius L. under different treatments and different periods were measured, and the effects of different water and nitrogen treatments on the growth and yield of Carthamus tinctorius L. were evaluated. 【Results】 The appropriate amount of irrigation and fertilization had a significant role in promoting the growth and development of Carthamus tinctorius L.. The plant height, number of branches, number of leaves and other agronomic traits of Carthamus tinctorius L. under W₂N₁ and W₂N₂ treatments were significantly higher than those under other treatments. The dry matter accumulation rate and amount, number of fruit balls per plant and number of seeds per fruit of Carthamus tinctorius L. under W₂N₁ treatment reached the highest level, and the filament yield and grain yield under W₂ treatment were significantly increased by 8.09% and 20.84% compared with W₁ and W₃ treatment, under N₁ and N₂ treatment, the difference was small, but they were significantly increased by 10.69% and 25.66% compared with N₀ treatment. 【Conclusion】 Irrigation amount and traditional fertilization amount (W₂N₁: 1,500 m³/hm² of irrigation and 300 kg/hm² of fertilization) are combination of water and nitrogen, which can promote the growth and development of Carthamus tinctorius L., provide water and fertilizer utilization efficiency, increase dry matter accumulation, coordinate yield components, thus achieving the goal of high yield and quality of Carthamus tinctorius L..