Louisiana Rice: Trying To Put A Dollar Value On Flood Losses08/17/2016
Rain over the weekend in parts of southwest Louisiana – where approximately 75% of the state’s rice crop is grown – has totaled over 24 inches in many places. This rainfall came in a very short window and has caused many low lying areas, including many rice fields, to flood.
Backwater flooding is still rising in many rice production areas.
While rice is grown in flooded fields, water that overtops rice can cause yield losses just like it can in other crops. The damage can happen much faster when the grain is ripe and ready to be harvested.
When harvest-ready rice is submerged, the grain can imbibe water and germinate. This causes the rice to sprout at the heads. Sprouted rice, if harvested soon after sprouting, can still be harvested. The quality of the milled grain is considerably lower, though.
Fortunately, there is a market for a limited amount of this type of rice. Mature rice that is submerged for several days can rot and become rancid. This rice would not be harvestable and would be considered a total loss.
Another problem that can happen with rice following storm events is lodging. Lodging is a term that refers to crops that lean and, in the worst cases, fall over and lay on the ground. In most cases lodging is caused by strong winds, rain (which makes the panicles top heavy), wet soils, and weak stalks.
Lodged rice that lays flat on the ground is slow and difficult to harvest, and much of the rice is lost in the attempt. Lodged rice frequently sprouts at the head and can also become rancid because it typically holds moisture even when fields are not currently flooded. That results in reduced grain quality, reduced milling, reduced harvest eficiency, and significant economic losses to the producer.
Putting A Dollar Amount On Rice Damage Due To Flooding
Estimating the economic impact on rice of the floods so far is not easy. However, many have asked me for an estimate over the past couple of days, so I tried to do my best to come up with a number. Remember, my estimate is highly speculative and will probably change considerably before all of this is over.
I used the following information to make my estimate:
- I polled extension agents in every affected parish to determine how much rice was left to be harvested in their parish and how much of that is under water or will, most likely, be lost due to submergence or other issues. For our three largest acreage parishes (Acadia, Jeff Davis, and Vermilion), approximately 20% was currently left in the field with approximately 20% that was estimated to be lost.
- I coupled this with the most resent FSA certified acres by parish report, which states that we have approximately 430,032 acres.
- I used an average yield value (by NASS August 12) of 7,100 lb/acre.
- I estimated an average rice price of $11 per cwt.
With that approach, the estimated farm gate loss value to southwest Louisiana was approximately $14.3 million Note that this does not include potential ratoon rice losses. It also does not include infrastructure and equipment losses that will be significant to rice producers in the area.
Ratoon Rice Losses and Ratoon Regrowth Decline
Significant ratoon rice acres will also be lost due to the flooding. Rice first crop yields are estimated to be 7,100 pounds per acre (NASS report August 12). While not a record, this would be better than the 2015 average yield in Louisiana. We would like to see yields in the 7,600 pound per acre range, which we observed a couple of years ago.
Generally, when first crop yields are low in southwest Louisiana, we can make up some of those yield losses with the ratoon rice crop. We can boost ratoon rice yields by harvesting dry, manipulating the stubble by flail mowing or rolling, and by applying nitrogen fertilizer on dry ground followed by a very shallow flood of “clear” water.
Prior to the flooding, we were observing frequent afternoon showers in many parts of the southwest Louisiana rice production areas, which had slowed harvest and caused many fields to be harvested on wet soils. This caused rutting in the field, which reduces yield.
Wet soils also made it impossible to post-harvest mow, roll or flail mow fields, and nitrogen fertilizer was not applied on dry ground in many cases south of I-10. All of this was already reducing ratoon crop production potential for 2016.
Flooding of ratoon stubble can cause the ratoon stubble to die just like any other plant. If the ratoon regrowth is able to extend past the waterline, the ratoon crop should be OK. However, regrowth below the waterline for an extended period of time will be lost. Ratoon stubble not submerged but in high water can have problems, too.
Typically, ratoon water becomes dark brown and low in oxygen as organic matter from the first crop harvest starts to decompose. In addition, the dark water prohibits sunlight from penetrating in the water and reaching rice regrowth from the lower nodes and the crown node.
This can cause any regrowth that has started to die back. There is not a common term for this, so for now we will call it Ratoon Regrowth Decline (RRD).
If you are noticing RRD, the best management practice is to drain the water to a level that will allow sunlight and oxygen to reach the regrowth at the lower nodes. As the green regrowth from the lower nodes gets taller, the flood can be increased.
Source: Dustin Harrell, Louisiana Rice Extension