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Switchgrass Biochar Effects Two Aridisols
Get PDFThe use of biochar has received growing attention with regards to improving the physico-chemical properties of highly weathered Ultisols and Oxisols, yet very little research has focused on effects in Aridisols. The objective of this study was to investigate the effect of either low or high temperature (250 or 500C) pyrolyzed switchgrass biochar on two Aridisols. In a pot study, biochar was added at 2% w/w to either a Declo loam (Xeric Haplocalcids) or a Warden very fine sandy loam (Xeric Haplocambids) and then incubated at 15% moisture content (by weight) for 127 days; a control (no biochar) was also included. Soils were leached with 1.2 to 1.3 pore volumes of deionized water on days 34, 62, 92, and 127, and cumulative leachate Ca, K, Mg, Na, P, Cu, Fe, Mn, Ni, Zn, NO3-N, NO2-N, and NH4-N concentrations were quantified. After the incubation experiment had terminated, soils were destructively sampled for extractable Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Zn, NO3-N, and NH4-N, total C, inorganic C, organic C, and pH. As compared to the 250C, the 500C pyrolysis temperature resulted in greater biochar surface area, elevated pH, higher ash content, and minimal total surface charge. For both soils, leachate Ca and Mg decreased with the 250C switchgrass biochar likely due to binding by biochar’s functional group sites. Both biochars caused an increase in leachate K, while the 500C biochar increased leachate P. The 500C biochar reduced leachate NO3-N concentrations as compared to the control; however, the 250C biochar reduced NO3-N concentrations to the greatest extent. Easily degradable C, associated with the 250C biochar’s structural make-up, likely stimulated microbial growth which caused NO3-N immobilization. Soil extractable K, P, and NO3-N followed a pattern similar to the leachate observations. Total soil C content increases were linked to an increase in organic C from the biochars. Cumulative results suggest that the use of switchgrass biochar prepared at 250C could improve environmental quality in calcareous soil systems by reducing nutrient leaching potential
Development of vegetation based soil quality indices for mineralized terrane in arid and semi-arid ecosystems.
Get PDFSoil quality indices are often management driven and attempt to describe key relationships between above- and below-ground parameters. In terrestrial systems, indices that were initially developed and modified for agroecosystems have been applied to non-agricultural systems in increasing number. We developed a soil quality index in arid and semi-arid ecosystems of the Western US impacted by different types of geologic mineralization using the relationship between vegetation community parameters and soil abiotic and biotic properties. We analyzed these relations in soils associated with three different mineralization types: podiform chromite, Copper/Molybdenum porphyry, and acid-sulfate gold vein systems at four different sites in California and Nevada. Soil samples were collected from undisturbed soils in both mineralized and nearby unmineralized substrates as well as from waste rock and tailings. Aboveground net primary productivity, canopy cover and shrub density were measured for the vegetative communities. Minimum data sets were developed based on correlations between the soil and vegetation parameters, refined using principal components analysis, scored using non-linear functions, and combined into an overall soil quality index. The indices are comprised of one or two microbial parameters and three to six abiotic parameters, the latter consisting of nutrients and metals. Given the preliminary development of this approach, the parameters and combinations to arrive at a soil quality index for a given site cannot at this time be correlated or compared with that of another site. This soil quality index approach provides a means of quantifying disturbed ecosystem recovery resulting from mining, and could be applied to other disturbances in a way that readily distills the information for potential use by land managers
Quantification of bacterial indicators and zoonotic pathogens in dairy wastewater ponds
Get PDFZoonotic pathogens in land-applied dairy wastewaters are a potential health risk. The abundance and occurrence of 10 pathogens and 3 fecal indicators was determined by quantitative real-time PCR (qPCR) in 30 dairy wastewaters from southern Idaho. Samples tested positive for Campylobacter jejuni, stx1- and eaeA-positive Escherichia coli, Listeria monocytogenes, Mycobacterium avium, and Salmonella enterica, with mean recoveries ranging from 1,000 to 10,000 genome copies per mL of wastewater. The most dominant organisms were C. jejuni and M. avium, being detected in up to 21 and 29 of 30 wastewater ponds, respectively. The qPCR detection limits for the putative pathogens in the wastewaters ranged from 16 cells mL for M. avium to 1,689 oocysts mL for Cryptosporidum. Cryptosporidium and Giardia spp., Yersinia pseudotuberculosis, and pathogenic Leptospira spp. were not detected by qPCR
Advances in Irrigation: Select Works from 2010 Decennial Irrigation Symposium
Get PDFThis paper is an introduction to the Advances in Irrigation Special Collection in this issue of Transactions ASABE and the next issue of Applied Engineering in Agriculture of 14 papers selected from 88 papers and presentations at the ASABE 5th Decennial National Irrigation Symposium, December 2010, in Phoenix, Arizona. This symposium followed the objectives of the previous four decennial events to provide a forum to assess progress of research endeavors to advance the effectiveness of irrigation practices during the past 10 years, leading to further research priorities that respond to future challenges. The papers in this Collection address a wide range of topics grouped into broad categories: microirrigation, center pivot irrigation, crop water use for improved irrigation management, and smart irrigation controllers for landscape irrigation. While these papers are not inclusive of all irrigation work since the last decennial symposium, they do provide a snapshot of work considered important by researchers, funding agencies and other stakeholders. Many aspects of irrigation have changed since the first symposium in 1970. Although microirrigation is a small proportion of irrigated acreage, it will continue to increase in highly technical commercial food and fiber production as well as in subsistence farming. Center pivot irrigation systems have been an important tool to deliver water more efficiently in diverse settings. Advanced telemetry and control systems, developed during the past 10 years, are now common options for center pivots, but challenges remain to integrate those hardware developments into crop management practices. Possibilities are emerging for adding monitoring devices to center pivots to match crop water needs with water delivery. Energy balance models continue to be refined as tools to estimate crop water use from both ground and satellite based data. Evapotranspiration estimates are evolving from single location weather stations to whole-field or regional scopes. Finally, “smart” irrigation controllers have coupled evapotranspiration estimation or soil-water sensing with automated irrigation system water delivery. These controllers can increase the precision of irrigation to match crop or landscape water needs. Irrigation will continue to be an important practice for producing the world’s food. The irrigation research and education professions will need to respond to food production challenges with even more refined irrigation systems and water management in the next 10 years. However, research investment in irrigation continues to decline when important issues exist, such as: maintaining agricultural profitability with declining water supplies, integrating sensor-based information for real-time autonomous or semi-autonomous management, competition for limited water supplies between agriculture and other sectors, increasing energy cost, environmental impacts of irrigation, and use of alternative water sources (i.e., lower quality) for irrigation
Germplasm Release: Tissue Culture-Derived Curly Top-Resistant Genetic Stock
Get PDFThe USDA-ARS sugarbeet research program at Kimberly is focused on discovering novel genes for resistance to beet curly top and other economically important diseases. It is vital in genetics research to develop uniform breeding lines and genetic stocks to study inheritance, gene transfer (through conventional hybridization), and molecular genetics research. This process requires several one-year inbreeding cycles in sugarbeet because the plant is biennial and the public germplasm has much genetic diversity. We have adopted a well-established tissue culture approach to develop a type of pure breeding lines called ‘doubled haploid line’ (DHL) from unfertilized ovules. KDH13 (PI663862) genetic stock was released to public breeders and seed companies by the USDA-ARS Kimberly sugarbeet program, in cooperation with the Beet Sugar Development Foundation .This principal investigator has been deposited at the Western Regional Plant Introduction Station (WRPIS) in Pullman, WA. KDH13 is the first publically available sugarbeet genetic stock that is highly resistant to curly top. It has performed better than the curly top resistant check, Hilleshog PM90, in two greenhouse experiments (9 replications per treatment and 6 leaf hoppers per plant in a clip-cage) and same as the resistant check in the 2011 Curly Top Nursery in Kimberly, ID. This breeding line is currently used to develop beet leafhopper populations that carry a single virus species. Having a genetically uniform line eliminates the normal genetic variation between plants when we are testing for specific virus species. KDH13 is monogerm, self-fertile, and highly resistant to bolting. It has light green, upright, narrow leaves, and a small compact canopy. It’s susceptible to rhizomania, caused by the beet necrotic yellow vein virus (BNYVV), and powdery mildew (caused by Erysiphe polygoni). KDH13 can be an ideal donor of curly top resistance in hybrids, or used for backcrossing and inheritance studies of other economically important traits. The initial sugarbeet ovule culture work was performed under contract by a private company
Effect of Growth Promotants on the Occurrence of Endogenous and Synthetic Steroid Hormones on Feedlot Soils and in Runoff from Beef Cattle Feeding Operations
Get PDFSupplements and growth promotants containing steroid hormones are routinely administered to beef cattle to improve feeding efficiency, reduce behavioral problems, and enhance production. As a result, beef cattle manure will contain both synthetic steroids as well as a range of endogenous steroids including androgens, estrogens, and progestogens. A two-year controlled study was conducted in which beef cattle were administered steroid hormones via subcutaneous implants and feed additives and the occurrence of sixteen endogenous and synthetic steroid hormones and metabolites was evaluated in runoff from beef cattle feedlots and in manure and soil collected from feedlot surfaces. Samples were extracted and analyzed using liquid chromatography tandem mass spectrometry for metabolites of the synthetic androgen trenbolone acetate, 17 alpha-trenbolone, 17 beta-trenbolone, for the non-steroidal semi-synthetic estrogen agonist, alpha-zearalanol, and the synthetic progesterone melengesterol acetate, as well as a wide range of endogeneous estrogens, androgens, and fusarium metabolites. Synthetic steroids including trenbolone metabolites and melengestrol acetate were detected in fresh manure and in feedlot surface soils from cattle administered synthetic steroids at concentrations up to 55 plus or minus 22 ng per g dry weight (dw) (17 alpha-trenbolone) and 6.5 plus or minus 0.4 ng per g dw (melengesterol acetate). Melengesterol acetate was detected in 6 percent of runoff samples from feedlots holding cattle administered synthetic steroids at concentrations ranging up to 115 ng per L. The presence of melengesterol acetate in runoff from beef cattle feeding operations has not been previously reported. Synthetic steroids were not detected in manure or runoff from control cattle. A wide range of endogenous hormones were detected in runoff and feedlot surface soils and manure from cattle given synthetic steroids and from control cattle, with no statistically significant differences in concentration. These results indicate that runoff from confined animal production facilities is of environmental and public health concern regardless of the use of growth promotants
Diversity of Bacteria and Archaea in hypersaline sediment from Death Valley National Park, California
Get PDFThe objective of this study was to phylogenetically analyze microorganisms from the domains Bacteria and Archaea in hypersaline sediment from Death Valley National Park. Using domain-specific primers, a region of the 16S rRNA gene was amplified using PCR, and the product was subsequently used to create a clone library. A total of 243 bacterial clones, 99 archaeal clones, and 209 bacterial isolates were examined. The 243 clones from Bacteria were affiliated with the following groups: the Bacilli (59 clones) and Clostridia (1) of the Firmicutes, Bacteroidetes (90), Proteobacteria (27), Cyanobacteria (18), Gemmatimonadetes (41), candidate division OP1 (5), Actinobacteria (1), and the Deinococcus-Thermus division (1). Within the class Bacilli, 46 of 59 clones were tentatively identified as 10 unclassified species. The majority of bacterial isolates (130 of 209) were more closely related to the Bacillus subtilis-B. licheniformis clade than to any other recognized taxon, and an Ecotype Simulation analysis of B. subtilis relatives identified four previously unknown ecotypes. Several new genera were discovered within the Bacteroidetes (4) and the Gemmatimonadetes (2). Of the 99 Archaeal clones, 93 were tentatively identified as belonging to three new genera within the Halobacteriaceae; other clones represented novel species within each of four established genera
Evaluation of center pivot sprinkler wind drift and evaporation measurement technique
Get PDFWind drift and evaporation losses (WDELs) are an often discussed topic in regards to center pivot sprinkler irrigation efficiency. Opinions on the magnitude of WDELs vary widely, in part due to the wide variation in WDEL values published in the literature. The magnitude of WDELs reported in the literature range from 2 to 45%. The common technique employed to measure WDEL is to use catch cans and compare the measured volume of catch with the volume of water applied based on sprinkler nozzle size, operating pressure and spacing with the difference being WDEL. The inaccuracies of catch cans resulting from wind effects on catch efficiency and evaporation of water from the catch can prior to measurement have led to the wide range in WDEL reported in the literature. The objective of this project was to develop and evaluate a methodology for measurement of WDEL from center pivot sprinklers using a combination of applied water collectors, bromide tracer and air samplers. The evaluation criteria were the magnitude of water volume balance error. A methodology for measuring wind drift and evaporation loss from center pivot sprinklers was developed and field tested under limited wind speed conditions. Volume balance errors ranged from 0.1 to 7.1%. The cause for the large errors on two occasions has not yet been determined. The percent of applied water aerosolized and measured as drift was found to be linearly correlated with wind speed. Overall, the limited tests show the methodology to be feasible for measuring WDEL from center pivot sprinklers. Tests in higher wind speeds are needed to validate the methodology as is determination and elimination of the cause for the high volume balance errors
Biochars impact on soil moisture storage in an Ultisol and two Aridisols
Get PDFDroughts associated with low or erratic rainfall distribution can cause detrimental crop moisture stress. This problem is exacerbated in the USA’s arid western and southeastern Coastal Plain due to poor rainfall distribution, poor soil water storage, or poorly-aggregated, subsurface hard layers that limit root penetration. We hypothesized that soil physical deficiencies may be improved by biochar applications. Research indicates a single biochar will not serve as a universal supplement to all soils; consequently, biochars may need to be designed with physico-chemical properties that can ameliorate specific soil physical deficiencies. We conducted a laboratory study that examined the effect of biochar on soil moisture retention and aggregate formation. Eight biochars were made from four feedstocks at two different pyrolysis temperature classes (500°C; 932°C) and were characterized for their physical and chemical properties. In addition, we included a biochar made using fast pyrolysis of hardwood wastes. All biochars were mixed at 2% w/w with either a Norfolk loamy sand (Fine-loamy, kaolinitic, thermic Typic Kandiudults), a Declo silt loam (Coarse-loamy, mixed, superactive, mesic xeric Haplocalcids), or a Warden silt loam (Coarse-silty, mixed, superactive, mesic xeric Haplocambids). Amended soils were laboratory incubated in pots for up to 127 days. About every 30 days, bulk density was measured and then each pot was leached with 1.2 to 1.3 pore volumes of deionized water. Gravimetric and volumetric soil moisture contents were determined after free drainage had ceased and again 2 and 6 days after leaching. The Norfolk-treated soils were later dry-sieved, and the sum by weight of their 0.5- to 1.0-mm aggregates was determined. In general, the biochar surface area and surface tension increased when produced under higher pyrolytic temperatures (>500°C). After leaching, Norfolk soils treated with switchgrass biochars had the most significant increase in soil moisture capacities. Similar increases were found in the Declo and Warden soils. Formation of 0.5- to 1.0-mm aggregates in the Norfolk loamy sand varied with biochar. Biochars enhanced the moisture storage capacity of the Ultisol and Aridisols thereby potentially reducing the on-set of crop moisture stress; however, the effect varied considerably with biochar feedstock and pyrolysis temperature
Net Nitrogen Mineralization from Past Years' Manure and Fertilizer Applications.
Get PDFManure from the semiarid West’s dairy industries is a rich nutrient source, but its use for crops can be problematic because soil N availability from manure may vary substantially depending on the year of application. Experimental plots established in Idaho on a Portneuf silt loam (coarse silty, mixed, superactive, mesic Durinodic Xeric Haplocalcid) included six manure treatments and two non-manure treatments with four replicates. The six manure treatments included combinations of two manure rates, Man-1x (0.31 Mg total N/ha) and Man-3x (0.97 Mg total N/ha) applied in the fall either 1, 2, or 3 years previously. The two non-manure treatments were urea fertilizer applied per soil test (Fert) and a control with no amendment. We measured net N mineralization (0-30 cm) in the plots using buried bags in 2006, 2007, and 2009 for a sprinkler-irrigated barley, sugarbeet, and dry bean crop, respectively. This resulted in i) two years of net N mineralization data for each manure rate applied 1, 2, or 3 years prior to measurement; and ii) one year of data for each manure rate applied 4 or 5 years previous to the measurement year. A 5-year decay series for each of the two manure rates was derived from functions fitted to the net N mineralization data, expressed as a fraction of total manure-N applied. The decay series (y1-y5) for the manure-1x treatment was 0.23, 0.12, 0.10, 0.09, and 0.08 while that for the manure-3x rate was 0.20, 0.08, 0.05, 0.04, and 0.03. Soil at the 30-to-60-cm depth contributed up to 28% of the total N mineralized in the 0-to-60-cm soil layer of manure-amended soils in the 3rd year after application, with lesser amounts contributed in earlier years due to immobilization. The efficacy of N mineralization processes decreased as the manure application increased, thus using a single decay series to predict N availability across a range of manure application rates could lead to substantial estimation errors