Towards the highly effective use of precipitation by ridge-furrow with plastic film mulching instead of relying on irrigation resources in a dry semi-humid area

• The highest yield of 9.7 t ha−1 was achieved under well-irrigated practice (WI).
• Ridge-furrow with plastic film mulching practice (RFPFM) resulted in up to 74% of the yield of WI.
• RFPFM increased water-use efficiency by more than 50% compared with CK and WI.
• RFPFM increased the N fertilizer productivity and N uptake efficiency by 53% and 44% compared with CK

The development of water-saving cultivation techniques has been attracting increased attention worldwide. A rainwater harvesting system known as ridge-furrow with plastic film mulching (RFPFM) has gradually become a promising cultivation method in semiarid rain-fed ecosystems in China. However, it is not well documented, whether this system can be practiced in a semi-humid region where irrigation is available. Field studies comparing three cultivation patterns (rainfed flat planting as CK, RFPFM, and well-irrigated planting pattern: WI) across two different nitrogen (N) rates and two cultivars were conducted for two consecutive years to assess the potential role of RFPFM in improving the water use efficiency (WUE) of winter wheat in a dry semi-humid region of northwest China. The high soil moisture and favourable temperature during the seedling establishing period in the topsoil under RFPFM practice contributed to the emergence of the seedlings 2 days earlier than for CK. Its superiority, also resulted in longer growth duration but also resulting in earlier spikelet and spike differentiation, thereby increasing the grain number per spike, spike number per m−2 and wheat yield under RFPFM practice compared with CK. The highest yield of 9.7 t ha−1 was achieved in WI combined with a higher N application condition. RFPFM practice resulted in up to approximately 74% of the yield of WI treatment with higher N application, while increasing WUE by 53.7% and 46.3% compared with CK and WI practices, respectively. In addition, RFPFM practice, in comparison with CK, increased the N fertilizer productivity and N uptake efficiency by 52.5% and 44.2%, respectively, averaged across others treatment and years. We highly recommend RFPFM practices with the N rate of 75 kg ha−1 as a water-saving technology and a promising strategy to increase wheat yield and WUE in the current agro-ecosystem of northwest China.