Flood up and deal

Jarrod Hardke, University of Arkansas

DR. JARROD HARDKE
ARKANSAS
Asst. Professor/Rice Extension
Agronomist
University of Arkansas Cooperative
Extension Service
jhardke@uaex.edu

Toward the end of May and really into June, most of the rice crop will be ready to start flooding, depending on conditions. This is the time when we will begin to set our first yield component — number of tillers and with it the number of potential panicles. To start the crop off on the road to success, it’s important that we properly time our essential management decisions.

It’s critical that we get proper weed control going into flood so we limit, or hopefully remove, weed competition from our rice. A good residual herbicide program, coupled with any needed post-emergence products for emerged weeds, is critical to starting and staying weed free. Spending a little extra at this time is much cheaper than trying to get weeds back under control with salvage applications where we missed.

Most salvage applications are very expensive. There isn’t much we can throw out there that will act as a true “salvage.” Many turn into revenge applications where much of the damage is already done and the large weeds may or may not be controlled. Control them early with an intent to avoid salvage situations. Even when these fields end up clean, growers can be left wondering why yields were low — early season weed competition is real!

Consider using multiple-inlet irrigation to speed the time to establish a permanent flood on the entire field. This will provide you with the greatest nitrogen efficiency over the whole field. Additionally, herbicide activation and residual weed control will occur in a timely fashion and prevent us from getting behind there as well.

A quickly established, well-maintained flood should be combined with the use of a GreenSeeker reference plot (see the April edition of Rice Farming and the 2018 Rice Farming for Profit publication, http://uaex.edu/rice, for more information).

reference strip

Include a 5-foot-by-5-foot reference strip that has received about 1/3 cup more urea (above the preflood N rate).

This reference plot can help us to use a GreenSeeker handheld at midseason to see if we need any additional nitrogen at this timing. Where our preflood nitrogen is well incorporated in a timely manner, many will be surprised where midseason nitrogen is not recommended and that money can be saved.

It can also show us fields where we failed to get proper preflood nitrogen uptake and need to apply midseason nitrogen.
Each year, I’m surprised at the number of “automatic” fungicide applications made in rice. For diseases such as blast and the smuts, there is no threshold and we must make automatic preventative applications when we know we have fields or cultivars with these issues.

For sheath blight, there is an established threshold, and we need to use it to spend our money on fungicides when we need it rather than make automatic applications.

It’s nice to see an improvement in rice prices, but we need to be smart with our expenses to maximize economic return. Many day-to-day in-season questions can be answered with recommendations found in the 2018 Rice Farming for Profit publication.