Effect of Water Table Depth and Flooding on Yield of Millet
1969
Williamson, R. E. | Willey, C. R. | Gray, T. N.
Yields of millet (Pennisetum glaucum (L.) R. Br.) grown in both sheltered and nonsheltered soil tanks increased with water table depth to a depth of 76 cm. In the sheltered tanks yields were similar for all water table depths greater than 61 cm. The N, P, and K contents of plants grown grown with water tables at 15 or 30 cm in the sheltered tanks were significantly lower than for deeper water table depths. Except for the tanks with 15- and 30-cm water tables, the oxygen content by volume was generally above 18% at the 15-cm depth, indicating that the region of greatest root mass (0 to 8 cm) was probably well aerated. Since yields were affected by water table depths down to 76 cm, it appears that the few roots extending below the 8-cm depth were nevertheless necessary o supply nutrients to the plant. Yield data suggest that O₂ was low in a portion of the root zone where water tables were less than 76 cm below the surface. Two days of flooding 4 weeks before the First harvest reduced the first harvest yield 40%, but did not affect the second harvest yield. Flooding at earlier or later dates caused less yield reduction.
显示更多 [+] 显示较少 [-]