Circles for Rice Update | by Jake LaRue and Kelly Downing

Currently, the Valley Circles for Rice team is observing fields under center pivots in Brazil, Chile, Zambia, and Australia. Growth stages vary from 1-2 leaf to early tillering.

• Weed control is a challenge and becomes a big problem if the weeds are not controlled when they are small. Grasses in particular seem to be a problem and, in some cases, are taller than the rice.
• A plan and knowing available herbicide options when you start a rice crop is critical for pre-emergence and post-emergence treatment.
• Please follow the herbicide label. If the herbicide is not labeled for rice use, DO NOT use it.
• Irrigation management requires an understanding of the rice root zone from week to week. When talking "field capacity," we mean that when the soil is completely saturated and a rain event occurs, the rain would either run off the field or leach quickly through the root zone.  Due to this, in general, you should refill the root zone of the crop to within 15% or so of field capacity to allow room for a rain event.
• An example - rice at early tillering:
• Root zone -- 7.5 to 10 cm
• Soil -- silt loam
• Allow 30% depletion at this stage -- up to 60 mm
• Crop water use
• Confirm the evapotranspiration (ET) -- let's assume it is 7 mm/day
• Assume rice at this stage has a crop coefficient of .35 mm
• Daily use would be about ET x crop coefficient (7 x .35 = 2.45 mm)
• Center pivot can apply 9.5 mm/day
• Probably need to be applying about 6 to 7 mm every other day
• If you have soils that tend to crack, start irrigation during the tillering stage when cracks are 2 to 3 mm wide
• Both light, frequent applications and heavy applications can be a problem. Watch your wheel tracks and watch for runoff
• Check the crop root zone and confirm that you are refilling the profile without runoff or irrigation moving out of the root zone

Remember: the data from soil moisture sensors is only as good as the installation. Make sure your sensors are properly installed and calibrated, and use the "smell test", i.e. if something smells bad (if the readings seem bad), it probably is. Check conditions around the sensors periodically to make sure that what they report is the real situation in the field.


Have questions?  Please enter them into the Comment box below!

Sprinkler Packages 101 by Jerry Gerdes

I have just completed my first year as a member of the Valley Circles for Rice team, and I have learned much about the process of growing rice. Crop-specific information is very useful when selecting sprinkler package components for a center pivot or linear irrigation (lateral move) machine. The term "sprinkler package" refers to the collection of sprinklers, pressure regulators, drop components, and fittings used to mount the sprinklers to the machine.

The sprinkler package is designed to apply water evenly (ie: uniform depth throughout the field) and efficiently. This is to maximize crop yields, minimize water usage, and operating costs. Sprinkler choices are designed to operate at pressures in a range of 6-30 PSI, depending on the sprinkler model. Products called U-pipes and drop pipes (or drop hose) are used to mount the sprinklers below the span trussing. The combination of low-operating pressure and low-ground clearance maximizes the application efficiency of the irrigation water. This type of sprinkler package was used on all 2010 Valley Circles for Rice fields.

Soil type is an important consideration when selecting a sprinkler model for growing rice. More on this in my next blog entry next month.

Do you have questions on sprinkler packages and how they relate in rice production under center pivots and linears? Leave a comment in the box below or email rice@valmont.com.

Circles for Rice | 2010 Final Yield Report by Jake LaRue

Below you will find the final yield report for the 2010 Circles for Rice growing season in the United States, Ukraine, and Pakistan.

United States

Blodgett, Missouri - 201 bu/ac
Neelyville, Missouri - 186 bu/ac
Scott, Arkansas - 173 bu/ac
Sikeston, Missouri - 160 bu/ac
Crawfordsville, Missouri - 160 bu/ac
Eagle Lake, Texas - 149 bu/ac
Dyersburg, Tennessee - 130 bu/ac

Crimea, Ukraine - 55 bu/ac

Pakistan

AAS 501 (hybrid) - 122.8 bu/ac
HS 777 (hybrid) - 108 bu/ac
Superi (variety) - 81 bu/ac
Shantaj (hybrid) - 79 bu/ac
#385 (variety) - 68.6 bu/ac
Super Guard Basmati (variety) - 62.4 bu/ac

If you have any questions about the yields, or about the Circles for Rice project in general, please send me an email at rice@valmont.com .