DR. JOHN SAICHUK
I know there is an increasing interest in growing upland rice in some parts of the U.S., but unless we develop different varieties and invent new herbicides, I will remain in favor of lowland or paddy rice production. Historically, the primary purpose of growing rice in a flooded state has been weed control. Over the thousands of years of rice culture, varieties have been bred to grow under those conditions, and, as a result, trying to use the same varieties under upland conditions is likely to present a number of problems. If water issues continue to be a problem as they are in California and Texas, our plant breeders may have to introduce germplasm from upland rice varieties, and herbicide scientists will have to invent new chemistry. Upland rice is grown in several regions of the world where water or slope or soil type dictates this style of production. In most instances, upland rice varieties yield less than paddy or lowland varieties.
The introduction of Clearfield rice changed Louisiana from being a primarily water-seeded rice culture state to being a primarily dryseeded one. Unfortunately, we did not begin tracking water-seeded versus dry-seeded acreage until 2008, but the percentage of water seeded acreage dropped from 56 percent in 2008 to 32 percent in 2010. A rebound in water seeding occurred in 2012 and 2013, emphasizing one advantage of water seeding – rice can be planted when it is too wet to get a tractor in the field. The way this year is shaping up, we may see that percentage increase again.
The earliest rice production in Louisiana was called “providence” rice. It was grown in small plots by subsistence farmers as a source of food rather than a cash crop. Small levees were constructed around the plots, and it was “left to providence” whether it was flooded or not. Despite all the scientific advances in rice production, weather conditions influence everything from planting to harvest. Last year by March 15, we had almost half of our acreage planted; this year we will be lucky if 10 percent is planted by that date, and I suspect it will be much less than that. In 2012 and 2013, we experienced flood rains in January and February. This year, we had freezing rain on four separate events in south Louisiana and five in north Louisiana. What the last three years have in common is wet conditions that have either delayed or prevented dry seeding of rice, especially drill seeding. In 2012, a lot of farmers had planned to drill seed, but weather conditions caused many to abandon those intentions, flood fields and water seed. In some cases, they had delayed planting beyond the ideal planting date. In 2013, many were quicker to pull the trigger and water seed, having learned from the experiences of the year before. Most of the rice planted as of this writing was done by air because it is still too wet to get equipment into the field. The most successful rice farmers I have observed over the years have at least two traits in common; they adjust to what weather dictates, and they are good water managers. Effective, efficient water management means many different things to many different people.
Check Water Quality
High-yielding, high-quality rice production revolves around water management. An abundant supply of quality irrigation water is needed for optimum rice production, and the Missouri Bootheel is blessed with an abundant supply of good, clean water. Thirty acre-inches of irrigation water pumped per year is average for Missouri rice fields. Although our water supply is very good and relatively inexpensive to lift to the surface, it does cost money and fuel to do so. Most Missouri rice fields are precision-graded, and our rice is normally flooded at the fifth leaf or first tiller, and a two- to four-inch flood is held the entire season.
Yearly preplant field leveling or smoothing is essential for seedbed preparation, surface drainage and maintaining optimum flood depths. A landplane or float should be used to remove reverse grades, fill “potholes” and smooth out old levees, rows or ruts in a field. Rice can germinate under either soil or water, but not both. Therefore, maintaining a field surface that provides good drainage is important for stand establishment; controlling weeds, diseases and insects; maintaining desired flood depths; and providing a dry field for harvesting.
A water supply is adequate for a given field if you can:
- Flush in two to four days
- Flood in three to five days
- Maintain a uniform flood for the entire season It’s rare, but we can have isolated water quality and quantity problems in our Missouri rice fields. Knowledge of the quality and quantity of irrigation water is required for proper water management and high-quality, high-yielding rice.
Correct diagnosis of problems concerning irrigation water quality is critical for effective management. Water quality testing is an important step in diagnosing existing problems and identifying potential problems. Samples can be taken and tested at the University of Missouri Soils Lab at The University of Missouri Delta Center at Portageville. Several values are helpful in evaluating the quality of a particular water source. These include calcium concentration, bicarbonate concentration, chloride concentration, electrical conductivity (EC) and sodium absorption ratio (SAR). These can be found in Table 9-7 in the UAR Rice Production Handbook. Also, iron and magnesium can be a problem. For further information on taking a well sample, call Dr. David Dunn, University of Missouri Soil Lab, at (573) 379-5431 or Sam Atwell, Agronomy Specialist, at (573) 429-9141.
DR. JARROD T. HARDKE
Rice Extension Agronomist
University of Arkansas,
Cooperative Extension Service
Water right, water light
Every situation is different, but there are some basic water management principles that should guide us throughout the season.
Be prepared to flush your rice. This means getting your levees surveyed and up as soon as possible after planting, or survey them before you plant. The ability to flush will allow us to ensure we get an adequate stand and have the ability to activate our herbicides in the event we don’t receive timely rainfall. Flushing costs money, but so do the seed and herbicides we’ve applied – be prepared to get the most out of your seed and herbicides by flushing if it’s needed. Be able to establish and maintain an adequate flood. Some fields do not necessarily have this luxury. In an ideal situation, we want to be able to flood a field in three to five days and maintain it for the rest of the season.
For fields where this is difficult, there are a few practices that can help in the fight. Multiple-inlet irrigation allows fields to be flooded quicker by applying an equal amount of water across the field at once rather than “spilling” the water down through gates. Other benefits of this practice include reduced pumping time and cost, reduced water runoff from the field and reduced “cold water effects” to name a few. Another useful practice when a field takes a while to flood is to treat urea with a product that contains NBPT, which can buy you some time in establishing a permanent flood and help make the most of the urea applied.
Think long term. Developing the means for long-term water availability should always be in the back of our minds. Reservoirs and tailwater recovery systems are worth the investment when it comes to our ability to have reliable water resources in the future. Many are in better situations than they were 30 years ago when it was fairly common to have to choose which crop to water in a dry year. Ask someone who was farming then about having to use every drop of water on their rice and having nothing left over for their soybeans. Fewer things are more difficult to take than to manage a crop most of the way through the season and then see it lost due to a lack of water. While we’re in better shape now, we still have a ways to go in establishing more reliable water resources. Remember to think about your water management in both the short term and long term. Set up your field to be able to flush early and flood quickly. Don’t waste water with unnecessary runoff, and if you do have runoff, try to collect it for future use.
DR. JOE MASSEY
Mississippi State University Agronomist
Having been on the water-conservation bandwagon for decades, Mississippi rice producers have steadily ratcheted down their irrigation inputs while producing prodigious amounts of high-quality grain. As the saying goes, however, the best never rest, and the sobering reports coming out of drought-stricken California and Texas, the large-scale Bayou Meto and Grand Prairie irrigation projects in Arkansas and actions being taken by our own state authorities on the alluvial aquifer confirm that farmers are being asked to produce more with less. Luckily, innovation is second nature for producers. We have a group of rice farmers that consistently apply 22 inches or less irrigation with excellent yields. Their results support research indicating that rice requires a total of about 25 inches of water (irrigation plus rainfall) during an 80-day flood in Mississippi.
Common practices include use of multiple-inlet rice irrigation, personal involvement in flood management and maintaining freeboard in paddies to optimize rainfall capture. Levee gates, installed higher than normal to allow for increased rainfall-holding capacity, are used only as “emergency spills” to handle heavy rainfall because water movement between paddies occurs through the tubing. These farmers know that for every inch of water not pumped, or captured as rainfall, nearly one gallon of diesel per acre is saved. This translates into an average net savings of approximately $8 per acre when the cost of the tubing and labor are considered. If only 25 inches are applied, the savings increase to about $26 per acre, demonstrating that the practice saves both water and money.
Another common practice among these growers is their use of flow meters as management tools. Accurate flow rates are helpful when determining the number of gates to install in paddies using MIRI and absolutely necessary when using software such as Phaucet or Pipe Planner to optimize furrow irrigation of soybean, etc.
The business adage that “you can’t manage what you don’t measure” will hold increasingly true as irrigation timings and amounts are optimized to meet the agricultural needs of a water-constrained world. If a producer doesn’t know how his/her water use compares to statewide water-use averages (about 34 inches for rice), I recommend purchasing a portable flow meter to go along with any permanent meters that they may already have. A portable meter allows the measurement of flow rates on multiple wells, while also measuring seasonal water use on a particular field.
DR. BRUCE LINQUIST
UCCE Rice Specialist
Managing Rice with limited water
This year is shaping up to be one of the driest on record for California, and it is likely that agriculture water deliveries will be restricted. If that is the case, then “What is the least amount of water I can grow rice with without hurting yields?”
Unlike the southern United States, California receives little to no rainfall during the growing season, so all water is supplied by irrigation. Based on past studies, the amount of water delivered to a rice field ranges from four to 7.7 feet. Of this, evapotranspiration (ET) is roughly three feet; percolation in most soils is less than 0.3 of one foot (due to heavy clay soils and impermeable hard pan); seepage ranges from zero to one foot; and tailwater drainage is one to four feet.
These numbers suggest that rice can be grown using 4.3 feet of water if there is no tailwater drainage. Growing rice with less water than that will depend on the percolation and seepage characteristics of the field, variety, time of planting and end-ofseason drain management.
Here are some tips to reduce water use. First, if fields need to be fallowed due to limited water availability, fallow fields with high percolation/seepage potential or high salinity (no-spill water management makes salinity problems worse). Second, choosing shorter duration varieties will reduce the time period the field has to be irrigated. Rice typically needs to be flooded from planting to reproductive stage seven (R7, when one kernel on the main panicle is yellow; about three weeks after heading). On average, to reach R7, CM-101, M-104 and S-102 require 100 days; M-206 requires 104 days; M-202 and M-205 require 108-112 days; and M-401 requires 128 days. Shortening the period of irrigation can reduce ET by a couple of inches as well as reduce percolation and seepage losses.
Third, planting early increases water use as it increases the time to canopy closure and the period that the crop needs to be irrigated, which increases ET and percolation/ seepage losses. Therefore, early plantings should be avoided. Fourth, most growers pull their boards at the end of the season to drain the field in preparation for harvest, resulting in significant tailwater drainage losses. Instead, growers should attempt to turn off irrigation before needing to drain and allow the water to naturally subside rather than drain the field.
Determining when the irrigation water can be turned off depends on how much water is in the field, climate and soil properties (percolation and seepage). Fields with heavy clay soils can be safely drained by 21 to 24 days after 50 percent heading without risking yield loss and grain quality. Finally, even though it seems counterintuitive, we have not measured any difference in water use between drill-seeded and wet-seeded systems in California. For more on this topic, a video presentation has been prepared and is available at http://ucanr.edu/insights.
Dr. M.O.O “MO” WAY
Rice Research Entolmologist
Conserve water on farms and in homes
The topic this month is water, which for the Texas rice industry is a major concern due to the extended drought. It looks like for the third straight year, water will not be released from Lakes Travis and Buchanan for our rice farmers in Colorado, Wharton and Matagorda Counties. These lakes are now at about 38 percent capacity. Also, water for rice farmers in Brazoria County will be restricted, further decreasing rice acreage in Texas in 2014.
However, farmers east of Houston will receive enough surface water to produce rice in 2014. Thus, some rice farmers west of Houston are moving operations east of Houston to take advantage of more plentiful water. Also, some rice farmers west of Houston are drilling wells, which is an expensive endeavor – about $350,000 per well.
On a positive note, the Lower Colorado River Authority is requiring urban water users (e.g. folks in Austin) to only water lawns once per week. I don’t know how city governments plan to enforce this, but I have heard the water used to sprinkle lawns in Austin is about equal to the amount used to irrigate our rice crop along the Colorado River.
Yes, water is a precious and increasingly contentious commodity. We can all conserve water on our rice farms and in our homes. Planting early maturing varieties early can result in fewer flushes. Precision leveling fields and installing polypipe with multiple inlets can save water. Frequent monitoring of water boxes, levees and water depth can reduce water use. Controlling weeds in canals and ditches can save water. Capturing and utilizing rainfall by adjusting board height on water boxes can also reduce water requirements.
Good weed control in the field and on levees leads to higher yields and more efficient use of water (obviously, weeds compete with rice for water). Control of diseases and insects also ultimately leads to more efficient use of water. Which is better – provide water to a diseased/ insect-stressed rice plant or a healthy rice plant? Maybe we should look at water use on a production rather than acreage basis? In other words, do higher-yielding fields use the same, more or less water than lower-yielding fields? Thus, maybe a better measurement of water use is in terms of water efficiency – i.e. the amount of water required to produce 100 pounds of rice?
On the home front, we can reduce water usage considerably. Take quicker showers, don’t wash our vehicles so much, plant droughttolerant grass and ornamental plants in our yards and run the dishwasher and washing machines only when full. Also, install lowwater- use toilets and fix leaky faucets. Believe it or not, the average per capita water use in the United States is about 100 gallons per day – 30 percent to water yards, which is even more in arid areas like central Texas. One acre-foot of water is about 326,000 gallons.
Austin has a population of about 850,000. If each Austinite reduced water use just 10 percent (10 gallons per day), daily water savings would be about 26 acre-feet. Over one year, the savings would be almost 10,000 acre-feet of water – enough to provide water for about 5,000 acres of rice.
In addition, I have heard that leaky city water pipes can lose up to 20 percent of water piped to homes. If municipalities (e.g. Austin) repaired these leaks, another 52 acre-feet of water could be saved every day, which, over a year, equals the amount of water to irrigate about 9,000 acres of rice. Rice farmers have reduced their water usage dramatically. Now it’s time for industry and municipalities to do the same.