Wide-narrow row planting and limited irrigation improve grain filling and spike traits in winter wheat in arid regions

Winter wheat is a vital grain crop in Xinjiang and severe water scarcity in this arid region necessitates efficient irrigation strategies for sustainable production. A two-year field experiment (2022-2023) in northern Xinjiang was conducted to evaluate the effects of sowing patterns and drip irrigation levels on winter wheat growth and yield. Two sowing patterns were tested: uniform row spacing (CK1, 15 cm) and wide-narrow row spacing, comprising 13.3 cm + 13.3 cm + 13.3 cm + 20 cm (M1), 10 cm + 10 cm + 10 cm + 30 cm (M2), and 10 cm + 10 cm + 10 cm + 20 cm (M3). Four drip irrigation levels were applied: 4500 mm²/hm² CK), 3600 m³/hm² (D1), 2700 m³/hm² (D2), and 0 m²/hm² (D3). The results indicate that wide-narrow row spacing increased the single-plant dry matter weight, with the stem + sheath and spike allocation ratios at maturity increasing by 15.31% and 6.59%, respectively. Wide-narrow rows improved spike traits, particularly in the outer rows, increasing spike length and grain number per spike by 0.46% and 0.68%, respectively, and reducing sterile spikelets by 1.35%. Compared with the CK1D1 treatment, the M2D1 treatment significantly increased the number of spikes per unit area, number of grains per spike, and yield by 19.15%, 5.92%, and 19.10%, respectively, with no significant difference in thousand-kernel weight. These findings demonstrated that M2D1 treatment optimized yield and water-saving efficiency, providing critical guidance for winter wheat production in arid regions.