Progress 10/01/03 to 09/30/08
Outputs
OUTPUTS: Soil samples were removed from six sites in which winter and spring wheat were grown Locations were in South Dakota near the towns of Selby, Pierre, Brookings, Winner, Kennebec, and Wall. The SDSU Crop Improvement Association in concert with the winter and spring wheat breeders selected these site on the basis of a survey of locations for high potential for high concentrations of selenium in grain. All of these sites were on grain producer's fields. The results of the soil total soil selenium analysis indicated ranges from 0.42 ppm at a site near Selby to 1.01 ppm at a site near Kennebec. This is quite low compared to sites that have been reported in Lyman, Gregory, and Stanley counties. Grain selenium concentration of wheat varieties harvested at the sites mentioned above showed ranges that seem to correspond to total soil Se analyzed. Mean grain Se harvested from the Kennebec site in which total Soil Se was the greatest of sites measured generally had ranges of grain selenium concentration that are greater than other sites. However, the grain selenium concentration in all of these sites was much lower than the 2 ppm considered a standard in grain sales or even the higher 5 ppm Se concentration that would attract a premium on the marketplace. Measured concentrations were as follows; Selby (SW, .96 ppm), Pierre (WW, .33 ppm), Brookings (SW, .33 ppm, WW, .36ppm), Winner (WW, .57 ppm), Kennebec (WW, 1.06 ppm) , and Wall (WW, .42) There was a somewhat strong relationship between protein content and total grain selenium concentration). This is especially evident at higher protein concentrations where this relationship appears stronger than at low protein concentrations. It has been well known that selenium storage in the grain is concentrated in the crude protein component. Efforts to determine whether raising protein content with N management to increase total selenium in favorable sites is justified. Higher applications of soil applied phosphorous appeared to reduce the selenium in the grain. PARTICIPANTS: Not relevant to this project. TARGET AUDIENCES: Not relevant to this project. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Results of this study indicate that selection of location - year where high selenium can be found in grain is a most difficult process. In this study locations were selected that in the past have exhibited high selenium in grain but in the years of this study the selenium in grain seldom exceeded 2 ppm. Higher applications of soil applied phosphorous appeared to reduce the selenium in the grain while higher concentrations of protein correlated well with higher concentrations of selenium in the grain.
Publications
- No publications reported this period
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Progress 01/01/05 to 12/31/05
Outputs
This project has been working do determine management and environmental factors that influence selenium (Se) uptake by wheat. Our goal is to help producers manage their seleniferous soils to produce Se-rich wheat. The objectives of the project are to determine the spatial variability of available and conditionally available Se in seleniferous fields, and to discern differences in Se uptake among selected spring and winter wheat varieties as influenced by weather conditions and soil Se. Soil samples (total 450) were taken after harvesting of spring and winter wheat in performance trial fields at Wall, Winner, Selby, and Brookings used by the SDSU wheat breeders. Wheat samples (total 168) were collected for Se analysis. Soil samples were dried and passed through a 2 mm sieve and about 10g of each soil were fine-ground (0.25mm) for Se analysis. The soil samples have been analyzed for pH, EC and bulk density. Analysis for total and available soil Se is underway. Total Se
content in wheat is also being analyzed and the Se content between wheat varieties will be determined. Additional soil samples (660) were collected from the wheat fields adjacent to performance trials in Wall, Winner, and Selby for spatial variability study. Soil samples were taken to three depths (0-10, 10-30, 30-60 cm) to determine the vertical Se distribution and all sampling points had their longitude, latitude, and elevation determined by GPS. Theses samples have also been dried, ground, and measured for soil pH, EC and bulk density. We are in the process of determining total carbon and nitrogen. Some soil chemical properties variation has been measured among the sampling sites. Soil pH ranges 6.4 to 8.2 (average: 7.0) in Wall, 5.5 to 7.9 (average: 7.3) in Winner, and 5.7 to 8.2 (average: 6.4). Total Se is currently being quantified.
Impacts
Se rich wheat has the potential to be marketed to Se deficient areas of the world. One requirement to take advantage of this potential niche marked is a stable supply of Se rich wheat. Se content has been found to be quite variable from year to year. The information gained through this project will help producers to grow a steady crop of Se rich wheat.
Publications
- No publications reported this period
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Progress 01/01/04 to 12/31/04
Outputs
Selenium is an essential element for animal nutrition. There is a very narrow range for a diet to be sufficient in Se. Problems with animals expressing symptoms from Se deficiency and toxicity are well documented. Many of the soils in central South Dakota are considered to be seleniferious (greater than 2 mg Se/kg) and can create problems for producers. Therefore, finding the effects of crop management on Se uptake by crops like wheat would be beneficial for Se management in high Se areas. The objectives of this study were to 1) determine the effect of P fertilizer on Se uptake in four wheat varieties (Triticum aestivum L. var. Oxen, Granger, Arapahoe, and Wendy), 2) investigate changes in Se fractionation in an alkali, seleniferious soil when wheat is grown under heavy P fertilization. This study was conducted in f10-cm pots in a greenhouse. A Promise soil (Very-fine, Smectitic, Mesic Typic Haplustert) collected from Presho, South Dakota was diluted 10% with perlite
to improve its permeability and gently packed into the pots for the study. The Promise soil contained 5 mg/kg total Se (0.07 mg/kg soluble Se, 0.08 mg/kg ligand exchangeable Se, 1.56 mg/kg acid extractable Se, 1.17 mg/kg oxidizable Se and 1.36 mg/kg unavailable Se). The P fertilizer treatments were applied at three different rates (0, 100, and 250 mg P/kg) as mono-basic potassium phosphate. A blanket rate of 200 ppm N from ammonium nitrate was added to each pot. A completely randomized design with four replications was used in the study. Total biomass production significantly increased by 50% with P fertilization. A significant interaction between wheat variety and P was observed. Only a significant change in the potassium-phosphate extractable Se was measured in the soil. In general, extractable Se decreased with increasing P application; however, total Se concentration in soils was not measured to be significantly different. Total Se concentration in the wheat stems and grain
increased slightly with increased P application, but there was no significant difference at the 95% levels.
Impacts
Selenium levels in feed, forage and soils have a significant impact on agriculture. This study is investigating the impacts of management on selenium content in wheat grown on high selenium soils. The information gained will help producers make better informed decisions when managing their production on these high selenium soils. This could lead to less barren beef cattle due to selenium toxicity or possibly a value added product in selenium enriched wheat for selenium deficient areas of the world.
Publications
- Lee, S.H., J.J. Doolittle, D.D. Malo, and T.E. Schumacher 2004. Changes in Se Storage and Bioavailablilty in Soil After P Application. In ASA-CSSA-SSSA-CSSS Abstracts 2004 [CD-ROM] ASA, CSSA, SSSA, Madison, WI.
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