Micro-ridge-furrow rain harvesting cultivation: An adaptive strategy for improving yield and water productivity of rapeseed (Brassica napus L.) in seasonal arid regions of Southwest China

Improving the utilization efficiency of agricultural water resources serves as a fundamental strategy for alleviating agricultural drought and water scarcity and ensuring food security. Micro-ridge-furrow rain harvesting cultivation (MRF) boosts crop yields by increasing soil water storage, but its effect on winter rapeseed production remains unclear in seasonal arid regions. A field experiment was conducted to investigate the effect of MRF height (10 and 20 cm, denoted as H10 and H20, respectively) on the yield and water productivity (WP c ) of winter rapeseed in seasonal arid regions of Southwest China, using conventional flat planting (CK) as the control. MRF had a greater soil water content (SWC) in the ridge furrow and better root and shoot growth than CK, increasing rapeseed yield by 15.09 % and WP c by 15.96 % ( P < 0.05). MRF slightly improved the seed quality compared with CK by increasing the oil, protein, and glucosinolate contents by 3.59 %, 3.28 %, and 1.83 %, respectively. SWC in the ridge furrow was slightly 3.30 % greater under H20 than under H10. The root dry weight density, root length density, root surface area density, and root volume density under H20 increased by 13.10 %, 16.57 %, 15.91 %, and 11.84 %, respectively, compared with H10. The plant height (3.77 %), SPAD (1.40 %), stem diameter (8.69 %), aboveground dry matter (16.68 %), and yield components were higher under H20 than under H10. The seed yield, WP c , and economic benefits insignificantly increased by 6.78 %, 7.11 %, and 4.35 %, respectively, under H20 compared with H10. H20 partly improved the seed quality compared with H10, with the oil, protein, and glucosinolate contents increasing by 1.57 %, 1.91 %, and 0.85 %, respectively. Overall, a 20 cm MRF height is recommended for crop production to improve SWC, crop growth, seed yield, WP c , and economic benefits of winter rapeseed. The results provide a theoretical basis and technical support for the improvement of water conservation and efficiency in winter rapeseed production in seasonal arid regions. • Micro-ridge-furrow rain harvesting cultivation (MRF) is adoptable in seasonal arid regions. • MRF improved rapeseed yield by 15.09 % relative to the conventional flat planting (CK). • MRF increased crop water productivity (WP c ) by 15.96 % relative to the CK. • Yield, WP c , and seed quality of rapeseed increased slightly with micro-ridge height increasing. • MRF with a height of 20 cm is recommended.