Thursday, August 5, 2010

Is it time to drain my rice yet?

I realize that several farmers have already started draining, and even harvesting in some cases. However, I thought this might be helpful in light of the heat and drought conditions we are currently experiencing. Farmers are always interested in when I can quite spending money on irrigation and begin to prepare for harvest. This has been especially true this year in light of the high input costs already paid out for this crop. For the majority of the rice acreage, we recommend draining 25-28 days after 50% heading. This generally corresponds to the time when the heads have all turned down and most of the panicles have changed color at least half way down the panicle. The photos below illustrate what rice typically looks like 25 days after 50% heading. The three panicles in the second photograph were taken from the plot in the first photograph.

Research varies on the effects of earlier draining but some studies have reported yield losses as much as 10% when drained too early. Remember in this heat, soils dry quickly. Don’t over estimate the amount of time is will take for the soils to dry. One option to help reduce pumping costs is to establish a good flood 14 days after 50% heading and then let the field dry down. This works for some growers but others have indicated that removing levee gates is too difficult if the fields dry out before drain time. In hot, dry years like this year, you still may need to flush through the fields if you don’t get any rainfall to help the crop to mature. If you routinely must rut the field in order to get the rice harvested on time because the fields do not dry enough, earlier draining is a feasible option. This is usually the case on most heavy clay fields.

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