Progress 09/01/05 to 08/31/08
Outputs
OUTPUTS: Information from this research was delivered by one-on-one conversations with individual rice farmers; making oral presentations at meetings, field days and conferences; recording audio segments for local agricultural radio stations; and writing bulletins, newsletters and magazine articles. Extension articles were published and posted on the internet through University of Missouri Extension Publication Guide sheets and Mid-America Farmer/Grower magazine. The magazine is read by 56,000 medium to large size farmers. Information on new rice management systems were broadcast on radio station stations located in Caruthersville, MO; Kennett, MO; Paragould, AR; and Portageville, MO, and Dyersburg, TN. The radio program impacted production on 6 million acres of cropland. A story was produced and aired on a national farm television programs discussing ways to reduce losses from urea nitrogen fertilizer. Educational material about rice production practices was included on University of Missouri website at www.plantsci.missouri.edu/deltacrops. Rice growth models provide useful information to help farmers optimize scouting for pests and scheduling applications of nitrogen fertilizer. Research information developed from this research study was used to develop and improve rice computerized program in Missouri. Timeliness is very important in effectively controlling pests that occur at specific growth stages of crops. The University of Missouri released a growth and development program called the Missouri Rice DD-50 program, available on-line at http://agebb.missouri.edu/rice/ricemodel.htm. The rice program is often called a Degree-Day 50 (DD-50) program because it assumes that rice growth will not occur with average temperatures below 50oF. Demonstrations of the program were presented at rice schools, Missouri Rice Conference, and Rice Field days. Scientists performed maintenance work each year on the program to keep it up-to-date. Obsolete rice varieties are replaced with new varieties. PARTICIPANTS: The Missouri rice farmers provided check-off dollars which supplemented the funds provided by this grant to help pay labor and purchase supplies. Bruce Beck and David Guethle from the University of Missouri Extension Service organized Rice Field days at Qulin, Mo and Rice Conferences at Dexter, MO. Dr. Donn Beighley at Southeast Missouri State University helped with plot maintenace at the Missouri Rice Farm. TARGET AUDIENCES: The target audience for this research was rice farmers in the upper Mississippi River Delta region and other scientists conducting rice research around the world. We used extension presentations at field days and conferences and print media to provide the information to growers. Three peer-reviewed journal articles were published in journal produced by the American Society of Agronomy. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Research findings were developed for managing nitrogen, boron, and sulfur fertilization, seed rates, and rotation cropping for rice production in the upper Mississippi Delta region. A cooperative project between scientists in Louisiana, Mississippi, and Missouri showed that hybrid rice cultivars produced average yields 17 to 20% greater than conventional inbred cultivars using equal rates of nitrogen. However, whole milled rice was higher with inbred cultivars than hybrids at the same N rate. Nitrogen applied at panicle initiation increased yield, milling quality and decreased lodging. Seeding rate tests using high-yielding conventional rice cultivars showed that 15 seeds per square foot produce equivalent rice yields to the current extension recommended seeding rate of 20 seeds per square foot. To help farmers be sure that no additional mid-season N is needed, we developed a fast, inexpensive field test called the "yardstick method". Experiments at Qulin and Portageville showed that the method did a good job of predicting yield response to mid-season N. Leaf canopy is estimated by counting the inch numerals visible on a yardstick floating between rice row drills. At green ring rice growth stage, float a wood or plastic yardstick between two 7.5-inch rice drill rows. Standing between adjacent rows and leaning over the sampling rows, count the inch numbers showing on the yardstick (not hidden by rice leaves) out of 36 numbers possible. Two rice varieties were tested on clay and silt loam soils over three years. No yield response was produced from midseason N when fewer than 13 numbers were showing at green ring growth stage on a yardstick floating between drill rows. Digital cameras can also be used to estimate rice plant area for making midseason N decisions. A camera was mounted on a rod held above the plot. A computer program developed at University of Arkansas was used to determine the percentage of green pixels in each photo. No yield response was produced from midseason N when greater than 64% of the pixels were green color in digital images. Fifty soil samples from rice grower fields were randomly selected and tested for B. More than half of the samples tested below 0.25 parts per million (ppm) B by hot water extractions. In field tests, rice yields were increased more than 10 bushels per acre with B fertilization in two out of three years. Given the relatively low cost of boron fertilizers and the high value of rice grain, yield response to B could result in a 10:1 return to rice producers for their input costs. A study was conducted to evaluate boron fertilization for rice grown on a silt loam soil west of Crowley's Ridge. Adding sodium borate to proponil+ molinate increased the pH of the spray solution from 5.0 (without B) to pH 6.0 (with B). In a 3-year study, elemental sulfur took longer to become available to plants and was found to be unsuited for in-season applications. Twelve pounds S per acre before planting increased rice yields by 15 bushels per acre. Post flood sulfur treatments provided 50% or less of the yield potential of pre-plant treatments.
Publications
- No publications reported this period
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Progress 09/01/06 to 08/31/07
Outputs
Rice experiments on silt loam and clay soils were conducted to develop thresholds using visual and digital image measurements for predicting rice yield response to midseason nitrogen (N) applications. Pre-flood N was applied at five rates with and without two mid-season N applications of 34 kg N ha-1 at panicle differentiation and 7 days later. In each plot, a yardstick was floated on floodwater positioned between two center rows. Visible inch numbers were counted while standing above the rows. Digital images of canopy were analyzed to determine percent green pixels. Highest rice yields were most often achieved with 78 kg N ha-1 with midseason N or 118 kg N ha-1 without midseason N. No rice yield increase from midseason N was produced when fewer than 13 yardstick numbers were showing or more than 64 % of image pixels were green. Soil potassium and phosphorus buildup from fertilizer is being studied in a rice/soybean rotation. University of Missouri soil test laboratory
recommendations for phosphorus (P) and potassium (K) fertilizer are based on three components: target level, crop removal, and build-up. Target level is the amount of extractable nutrient found in a soil at which point applying more fertilizer containing the nutrient will probably not increase crop yields. Crop removal is how much the nutrient is reduced in the soil annually from harvested forage, grain, or fiber. Build-up is the additional fertilizer needed above crop removal to increase low- and medium-testing soil P and K to the target fertility levels. Soil P and K build-up can be slow or fast depending on the economic situation of the farmer. The current soil test recommendation system used by University of Missouri allows growers to select the number of years over which to build-up soils.
Impacts
A simple method was developed to aid farmers with midseason nitrogen decisions in dry-seeded, delayed flood rice. Excessive use of nitrogen on crops has been implicated as a cause of water pollution and hypoxia in the Gulf of Mexico. Research showed that an inexpensive wooden yardstick can be used to determine whether their rice fields need additional nitrogen at midseason by aerial airplane. In the past these applications were often automatic by farmers without their knowing whether they were really needed. Research was conducted to determine which build-up strategy is the most profitable to manage crop nutrients for rice/soybean in the upper Mississippi River Delta region. Treatments include an untreated check, 1-year, 4-year, and 8-year buildup fertilizer programs. After three years, fertilizer treatments increased soil test levels in rice and soybean plots compared to the untreated checks, but one year P and K buildup applications failed to increase P or K above
critical target levels. The order from high to low was 1 year buildup, 4 year buildup, 8 year buildup, and checks (untreated and N only). Rice and soybeans yields were higher with P and K treatments than untreated checks. Averaged across years, no yield difference was found between 4 and 8 year buildup programs.
Publications
- Dunn, D. and G. Stevens. 2007. Phosphorus management in a dry-seeded delayed-flood rice production system. Better Crops with Plant Food. International Plant Nutrition Inst. Vol. 91, No. 1:20-21.
- Stevens, G., A. Wrather, M. Rhine, E. Vories, and D. Dunn. 2007. Predicting rice yield response to midseason nitrogen with plant area measurements. Agron. Journal. (In press).
- Walker, T., J. Bond, B. Ottis, P. Gerard, and D. Harrell. 2007. Hybrid rice response to N fertilization for Midsouthern USA rice production. Agron. J. (In press).
- Bond, J. A., T. W. Walker, B. V. Ottis, and D. L. Harrell. 2007. Rice seeding and nitrogen rate effects on yield and yield components of two rice cultivars. Agron. J. (In Press).
- Dunn, D., B. Ottis, A. Wrather, G. Stevens, D. Beighley, M. Aide, and C. Dickens. 2007. Can we predict rice yields using remote imaging? pg. 20-21 (C. Dickens and D. Beighley, eds.) In Missouri Rice Research Update 2006, Southeast Missouri State Univ. Special Rep 01-2006. 28 Feb.
- Ottis, B., R. Tanner, and A. Wrather. 2007. The effects of rice seeding rate, nitrogen rate, and variety on sheath blight incidence and severity. pg. 49-53 (C. Dickens and D. Beighley, eds.) In Missouri Rice Research Update 2006, Southeast Missouri State Univ. Special Rep 01-2006. 28 Feb.
- Stevens, G., and D. Dunn. 2006. Soil fertility research at the University of Missouri-Delta Center pg. 42-59 (C. Synder and R. Large, eds.) In Proc. Southern Plant Nutrient Management Conf. Olive Branch, Mississippi, 3-4 Oct.
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Progress 09/01/05 to 08/31/06
Outputs
In March of 2005 a Ph.D. rice agronomist was hired to coordinate the rice project for the University of Missouri-Columbia Delta Research Center. Studies have been initiated to evaluated the effect of reduced rice seeding rates on rice yield and milling quality of three popular long-grain rice cultivars. This research is also being done in Louisiana, Texas, Mississippi, and Arkansas. Results have shown that seeding rates of 15 seed per square foot are adequate for producing optimum yield and milling quality. This rate of seed is significantly below what is currently recommended by University extension publications and recommendations. Also, studies have been initiated to determine the optimum rates and timings of nitrogen for several new rice cultivars, including 'Trenasse', 'Spring', 'Cybonnet', and 'Jupiter'. Results have indicated that a single preflood nitrogen application of 150 pounds per acre is sufficient for producing optimum yields on freshly-graded Sharkey
clay soils typical of the Mississippi Delta Region. These data will be presented to Missouri rice growers at the annual rice conference held in February. A study was initiated in 2006 to evaluate the interaction of tillage and irrigation practices for soybean following rice production. Recent data in the literature suggest that soybean yields following rice may be reduced due to the popularity of winter flooding for waterfowl habitat or the effects of flooding on soil edaphic factors and nutrient availability. One such study is investigating soybean seed treatments and preplant phosphorous applications on soybean yield following winter flooding for waterfowl. A second study is evaluating the long-term effects of rice on soybean yield by varying tillage and irrigation methods. A third study is evaluating several different soybean varieties and maturity groups following rice production to determine which varieties have the highest yield potential in a rice/soybean rotation. In 2006 a
combine harvester was purchased with anticipated delivery in March of 2007. This combine will be used to harvest small-plots of rice and soybeans. Additionally, this project continues to fund one full-time research technician, a Ph.D. rice agronomist, and two temporary summer laborers.
Impacts
The impact of this research will be lowering input costs for rice farmers by reducing seeding rates and determining the best nitrogen rates and timings for optimum rice yield. Additionally, determining the best crop rotation schemes for rice in the upper Mississippi Delta Region is of utmost importance for profitability and sustainability. Research conducted through this grant will attempt to make this determination.
Publications
- Dunn, D.J., Ottis, B.V., Wrather, J.A., Stevens, W.E., Beighley, D., and Aide, M.T. 2006. Can We Predict Rice Yields Using Spectral Reflectance at Midseason? Proc. 31st Rice Tech. Working Grp. In Press.
- Walker, T.W., J.A. Bond, and B.V. Ottis. 2006. The Effects of an Early Season N Application When Applied to Various Plant Populations. Proc. 31st Rice Technical Working Group. In Press.
- Walker, T.W., R.J. Norman, and B.V. Ottis. 2006. What is the value of applying early season N on clay soils? Proc. 31st Rice Tech. Working Group. In Press.
- Beighley, D., C. Dickens, R. Dickens, A. Kendig, B. Ottis, G. Stevens, D. Dunn, and A. Wrather. 2006. 2005 Missouri rice variety performance trials. University of Missouri, Agron. Spec. Rep. 01-2005:18-21.
- Beighley, D., C. Dickens, B. Ottis, R. Tanner, and D. Dunn. 2006. Nitrogen fertilizer options for new rice varieties in Missouri. University of Missouri, Agron. Spec. Rep. 01-2005:38-42.
- Ottis, B. and R. Tanner. 2006. Nitrogen validation for two new rice varieties on a freshly-graded clay soil. University of Missouri, Agron. Spec. Rep. 01-2005:46-47.
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