Yield loss compensation effect and water use efficiency of winter wheat under double-blank row mulching and limited irrigation in northern China

Maize straw residues as a surface mulching material would be an effective soil water-saving practice in wheat production for a wheat-maize rotation system in northern China. Additionally, combining a mulching pattern and limited irrigation could play an important role in enhancing the productivity of winter wheat. Therefore, open field experiments were carried out during 2012–2014 to study soil water content in depth, water use efficiency (WUE), soil temperature, wheat grain yield and root parameters under a mulching pattern [each-row mulching (ERM) and double-blank row mulching (DRM) with three mulching masses of 0. 4.5 and 9.0tha−1] and limited irrigation [no irrigation (I0) and one-time irrigation in winter (I1)].Results indicated that wheat yields increased (mean 3.3%) or decreased (mean 5.4%) a little under ERM groups with no irrigation. Irrigation for each row of mulch increased the wheat yield (mean 8.8%). With or without irrigation, yields under DRM0 were lower compared to ERM0, whereas, DRM4.5 and DRM9.0 had a higher grain yield than ERM4.5 and ERM9.0 (mean 25% under I0 and 18.8% under I1) as well as DRM0 (mean 24.1%). The DRM patterns with a high yield could have an equal effect with irrigation in winter. Additionally, irrigation could enhance the effects of DRM on wheat yield increase (mean 6.87tha−1in DRM4.5 and 7.06tha−1 in DRM9.0). Effective tillers and above-ground biomass would be the key factors for determining wheat yield, especially under certain mulching patterns, although these effects were not reflected in wheat roots.Mulching on soil temperature had a more significant difference in an early growth period than the later stages of wheat. An additional feature was that the DRM pattern had a persistent heat preservation effect in the regrowth stage, while there was a lower soil temperature in ERM groups in this stage when there was no irrigation. Mulching managed to shorten the period of negative accumulated temperatures of wheat (mean of 7days under ERM and 15days under DRM) under I0. Winter water irrigation enhanced the shorten effect to a certain extent. Mulching had a more significant water conservation effect in the overwinter stage with lower precipitation and higher soil evaporation. Soil water content under DRM groups was richer than ERM groups in the late growth stage, when there was lower plant density and evapotranspiration, but there was a higher yield and WUE (with a mean of 18.6% under I0 and 20.3% under I1).The results suggest that the DRM pattern optimizes soil temperature, water content, balance roots and group effects as well as increasing wheat yield. Thus, this approach could be a better field management option for wheat growth and yield production under the limitations of water in northern China.