Winter wheat grain yield, water use, biomass accumulation and remobilisation under tillage in the North China Plain

We conducted a two-year experiment (2007-2009) in the North China Plain with supplemental irrigation to investigate the effects of tillage practices on the water use, biomass accumulation and remobilisation of winter wheat. Five tillage treatments were tested: strip rotary tillage (SR), rotary tillage (R), mouldboard ploughing (P), strip rotary tillage after subsoiling (SRS) and rotary tillage after subsoiling (RS). SRS significantly promoted the changes in soil water storage (ΔS) at soil depths of 60 cm to 160 cm, and the lowest ΔS level was observed in the SR treatment. The 60 cm to 140 cm soil moisture content in the SRS treatment was higher by 10.84% than that of the SR treatment before sowing in 2008-2009 and lower by 14.85% at maturity. The lowest dry matter remobilisation during grain filling (DMR) was detected in the SRS treatment. This value was 22.22% and 30.27% lower than those of the SR treatment in 2007-2008 and 2008-2009, respectively. However, the SRS treatment exhibited the highest contribution of dry matter accumulation during grain filling (CDMRG), in which high flag leaf photosynthetic rate (Pn) was observed from anthesis to maturity. The SRS and RS treatments exhibited the highest grain yields (9237.20 and 9261.31 kg ha−1 for two-year average) with no significant difference between the two treatments. The highest grain yields for the two treatments were 10.76% and 11.05% higher than those of the P treatment, correspondingly. The average water-use efficiency (WUE) for the two growing seasons was 20.49 kg ha−1 mm−1 in the SRS treatment, which was higher than those in the SR, R, P and RS treatments by 17.02%, 13.42%, 8.73% and 3.83%, respectively. Hence, SRS would be a preferable tillage system for planting wheat in this region.