Abstract
Appearance of red rice (Oryza Sativa) as the main weed problem in rice production has forced producers and researchers to develop new irrigation techniques to control the weed. The Pin-Point irrigation method is one of these techniques, but little is know about the water balance and water use efficiency of the Pin-Point method in comparison to the conventional Flush-Flood technique. The water balance of Pin-Point and Flush-Flood were studied during the 1994 and 1995 growing seasons in Bewmont, TX. Three plots were subjected to the PinPoint irrigation technique and three to the Flush-Flood method. Nine non-weighing lysimeters per plot were installed to measure infiltration, transpiration and evapotranspiration. Three pots containing soil and three pots containing soil and plants were also installed in each conventional irrigation plot and weighed periodically to measure evapotranspiration during the drain period. Stomatal resistance was measured every two to three hours during daytime using a steady state porometer. Canopy temperature, soil surface temperature and water temperature were measured with an infrared thermometer. A net radiometer was installed in each plot to measure net radiation. The Pin-Point method used less water than the Flush-Flood method. There were no significant yield differences between the two methods. The Pin-Point method produced earlier maturity of the crop and suppressed weed development. No herbicide was necessary in the Pin-Point plots. During the period when the Flush-Flood plots were drained, the net radiation was slightly lower than in the Pin-Point plots, and the stomatal resistance was always higher. Also the canopy temperature was higher in the Flush-Flood plots compared to the Pin-Point Plots during the drained period. These results suggest that the Pin-Point method can be useful not only to suppress red rice, but also to save water. Also the earlier maturity of the crop under the Pin-Point irrigation regimen increases the probability of a good harvest in the ratoon crop.
Roel Dellazoppa, Alvaro (1996). Water balance of Pin-Point and Flush-Flood irrigated rice. Master's thesis, Texas A&M University. Available electronically from
https : / /hdl .handle .net /1969 .1 /ETD -TAMU -1996 -THESIS -R64.