Another pathway between tillage and maize yield through soil moisture was also highlighted by SEM model (Fig. 2). It is worth noting that this pathway indirectly contributed to maize yield through maize height, which can be considered as a morphometric predictor of maize yield (Boomsma et al., 2010 and Yin et al., 2011). However, only height at the V12 stage was included in this study (Fig. 2), indicating that the maize height at the V12 stage rather than at the V6 stage can serve as an accurate indicator of maize yield. Our observations agree well with the reports of Yin et al. (2011) that the strongest relationships between maize yield and maize height were presented at the V12 stage. In addition, the SEM model also emphasized that maize height was directly regulated by soil moisture (Fig. 2), suggesting that soil moisture are important for maize height both before sowing and at the V12 stage. Abrecht and Carberry (1993) stated that non-lethal water deficit during the growth of maize results in marked reduction in plant height. The findings in this study are in agreement with the reports of Verhulst et al. (2009), which affirmed that soil water is one of the vital limiting factors of agricultural system.