Thursday, June 3, 2010

Circles for Rice | Weekly Update

United States

The rice under center pivots continues to develop. Field scouting has been focused on irrigation scheduling, wheel tracks, and weeds. Most of the rice is actively tillering and is beginning to close the canopy

The below graph is current soil moisture data for one rice field that we are reviewing this year.  Note the green line - it is a measure of soil temperature.

We are most interested in the blue line.  This represents the moisture sensor at 4", which is the distance the rice roots have reached.  Note that on May 28th,  June 1st, and June 3rd, the blue line drops - this is from the soil receiving water, which, in each of these cases, is irrigation; rainfall would show up similarly.  After each irrigation application, the blue line gradually increases; this is representing moisture use by the crop.

Our goal is to manage the highs and lows of this cycle to promote good crop growth and efficient water use.


  1. Hi jake

    Are you using any of this information to 'schedule' the irrigations? If so what is the trigger? And I am curious about the red line and why it drops off after the last irrigation!

    Cheers Ben

  2. Thank you for your comment, Ben.

    Now that the rice roots have begun to move into the area of the moisture sensors we use it as one indicator. To this point in the growing season we have been focused on maintaining a soil moisture depletion of 20% or less in the root zone which has been 0 to 2 in (0 to 5cm). As we move forward in the season and depending on the soil we will define levels that we want to stay between.

    We have begun using the University of Arkansas irrigation scheduling program for the rice that is into the tillering growth stage and will use it to assist in projecting ahead the irrigation requirement based on the crop growth stage and anticipated temperatures.

    The red line is the next deeper sensor (8in / 20cm) and it also saw some of the irrigation indicating there is good soil moisture for the rice root system as they move deeper.