Over 3 million acres of rice are grownannually in the United States, primarily inthe Lower Mississippi Alluvial Valley (theDelta). In fact, the Delta regions ofArkansas, Louisiana, Mississippi andMissouri produce more than 2 millionacres of rice annually. Americans trulyenjoy rice as a side-dish, as evidencedby consumption of almost 27 pounds perperson in 1998. Not only are people par-tial to rice, but it is also an important foodfor waterfowl, especially mallard, north-ern pintail, teal, and several species ofgeese.

Indeed. rice fields provide critical habitatfor large numbers of North America’swintering waterfowl, shorebirds, andother wetland birds. However, only about10% of the rice acreage in the Delta iscurrently managed to provide winter wet-lands for waterfowl. Thus, extraordinarypotential exists on rice lands for increas-ing the availability of wetland habitat forwaterfowl and other waterbirds.

Scientists in the Forest and WildlifeResearch Center (FWRC) at MississippiState University recently investigated thepotential values of winter-flooding ricefields and found the benefits were

tremendous for both waterfowl and farm-ers. The team of FWRC researchers,composed of doctoral student ScottManley, Dr. Rick Kaminski (Wildlife &Fisheries), Dr. Stephen Schoenholtz(Forestry), and research assistant JanetDewey (Forestry), examined how differ-ent post-harvest treatments and winter-water management in ricefields affectedsoil erosion, water quality, rice-strawdecomposition, weed control, and water-fowl food availability. The research wasconducted during winters 1995-1997 andincluded 72 harvested rice fields, encom-passing over 3,000 acres. Experimentswere conducted in the major rice-produc-ing areas in the Mississippi Delta, includ-ing Bolivar, Leflore, Sunflower, andWashington counties.

The scientists’ primary objective was totest if winter-water management wouldbenefit the environment, agriculture, andwaterfowl. Another objective was to esti-mate potentialcost savings inspring-field prepa-ration to farmerswho held water onrice fields during ,winter.

While environmental and wildlife conservation are trulyimportant, practices which also decrease farming costs aremost readily adopted by producers. Winter-water manage-ment of rice lands is such a practice.

Soil conservation and water-qualitymanagement in winter-flooded ricefields

Conserving soil and improving water quality are important inprotecting our nation’s natural resources. Experiments byFWRC scientists showed that winter flooding conserved soiland increased quality of runoff waters, especially when ricefields were not disked after harvest. Fall-disked fieldsallowed to drain freely after winter rains lost about 1,000pounds of soil per acre (Figure 1). Fields with drain pipesclosed to impound water during winter and with stubble leftundisturbed after harvest lost only 31 pounds of soil peracre. Flooding rice fields not only reduces the impact ofrain on exposed soils but also allows fields to act as settlingbasins and retain sediment and nutrients.

Winter-water managementas a tool for spring-field preparation

By early spring, rice farmers must contend with challengesin field preparation for planting, such as disposal of remain-ing rice straw and growth of cool-season grasses andweeds. Reduction of rice straw is particularly challengingas it is resistant to physical degradation and decay, but itmust be disposedo f t o f a c i l i t a t eplanting. FWRCresearchers found

that winter floodingwas as effective as

the estimated 4.5 tons per acre of rice straw left after har-vest (Figure 2). Elimination of fall-disking operations couldsave rice growers an average $14.13 per acre. The combi-nation of fall disking and winter flooding reduced straw mostsignificantly (68%), although disking incurs an addedexpense. The researchers also found that winter floodinginhibited germination and growth of cool-season grassesand weeds (Figure 3). If rice growers could eliminate aerialapplications of spring “burn down” herbicides as a result ofwinter flooding rice fields, they could save an average of$13.19 per acre.

Winter-managed rice fields providehabitat for wetland wildlife

Researchers and rice growers know that rice left after har-vest is an excellent source of food for waterfowl. However,the availability of ‘waste rice’ decreased 79-99% betweenharvest in August-September and early December whenwaterfowl typically arrive in the Delta in significant numbers.Researchers speculate that this decrease in waste rice dur-ing fall is due to a combination of factors, including germi-nation of seed laying on the ground, decomposition, andconsumption by rodents and birds. The decrease in wastegrain has potentially serious implications for the foragingcarrying capacity of rice fields and habitat needs for winter-ing waterfowl. Although availability of waste rice is muchless than anticipated, the researchers found that floodedfields support winter populations of aquatic invertebrates,which are an important source of protein and minerals forwaterfowl and shorebirds. Nevertheless, the researchersare concerned that winter food for ducks and geese may be

thus, a new research ini-limited in Delta rice fields;

tiative is underway to vali-date these findings anddevise managementstrategies to counter pos-sible food shortages forwintering waterfowl.

fall disking inreducing by 53%

Managing winter water in rice fields is relatively easy andinexpensive for rice growers because rice is grown in anaquatic setting. By following the procedures below, a winterflooding project should be successful.

1. Maintain water control systems and levees usedfor rice culture to impound winter rainfall. Thesesites are ideal for developing wintering habitat.

2. Consider refraining from fall disking to savemoney and prevent incorporation of ‘red rice’seeds into soils.

3. Hold water on fields throughout winter.

4. As spring approaches, drain fields gradually toconcentrate aquatic invertebrates and exposemud-flats for feeding waterfowl and shorebirds.

Overall, winter flooding of harvested rice fields was deter-mined to be a valuable conservation practice that benefitsthe environment, farm operations, and waterfowl. Winter-water management is an excellent example of how agricul-ture can be compatible with wildlife management. Thisresearch also reaffirmed the importance of conserving othernatural habitats, such as bottomland hardwood forests andmoist-soil wetlands, to provide alternative foraging areas forwintering waterfowl when waste rice is in short supply.

Figure 1

EXPORTSSUSPENDED SOLIDS

Figure 2

Figure 3

WINTER WEED GROWTH IN RICEFIELDS

Research conducted byRichard Kaminski

Scott ManleyStephen Schoenholtz

Janet Dewey

For moreinformation contact:

Bob L. Karr,Interim DirectorForest & WildlifeResearch Center

Box 9680Mississippi State, MS 39762

662-325-2952Fax: 662-325-8726

bkarr@cfr.msstate.eduhttp://www.cfr.msstate.edu

Karen Brasher. Editor

FwFGwF-148

Financial sponsors of this research wereDow AgriScience. Inc.; the Institute forand and Waterfowl Research, DucksUnlimited, Inc.; Federal Aid in Wildlifeoration through the MississippiDepartment of Wildlife, Fisheries andMississippi Rice Promotion Board;Mississippi Water Resources ResearchInstitute; National Fish and WildlifeFoundation; U.S. Geological Service’sPatuxent Wildlife Research Center; U.S.and Wildl i fe Service’s LowerMississippi Valley Joint Venture; andMississippi State University’s Forest andWildlife Research Center. Field research

was conducted on the following farmsAguzzi, Arant, Circle-H, Morgan, Murrell,Opossum Ridge, and Tackette. Technicaland logistical assistance was provided byDelta Wildlife Foundation, MississippiState University Extension Service,Mississippi Department of Agriculture andCommerce, Mississippi Farm BureauFederation, U.S. Department ofAgriculture’s Natural ResourcesConservation Service, and the U.S. Fishand Wildlife Service’s MississippiWetland Management District and theNoxubee National Wildlife Refuge.

This Research Advance was based upon the following doctoral dissertation: Manley, S.W.1999. Ecological and agricultural values of winter-flooded ricefields in Mississippi. Ph.D.Dissertation, Department of Wildlife and Fisheries, Mississippi State University.