Effect of integrated rice-duck farming on rice canopy structure index
稻鸭共作对水稻部分株型结构指标的影响

Although rice canopy structure is a critical factor that influences rice yield and quality, few research has been conducted on the effects of rice-duck farming on rice canopy structure. In a field experiment therefore, canopy structure characteristics at tillering and full-heading stages of late rice were compared between rice-duck farming and conventional rice farming (control) treatments. The results showed that rice-duck farming increased rice canopy width but decreased basal width. Furthermore, the leaf loose rate of rice-duck farming increased by 12.2% and 42.3% at tillering and full-heading stages, respectively, compared with the control. Rice-duck farming lowered leaf length, opening angel and drooping degree of the fourth and third leaves. The opposite effects were, however, noted for the second and flag leaves. This made the upper leaves flatter and the lower leaves more erect than the control treatment. This in turn enhanced leaf area distributed in upper canopy horizon. Rice-duck farming increased rice basal leaf height. Compared with the control, this resulted in significant differences at full-heading stage. The findings of the study indicated that rice-duck farming had positive effects on rice stem and tiller development in the early and middle growth stages. It improved growth of upper functional leaves which was beneficial to rice yield formation at late growth stage.