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Fate of biosolids trace metals in a dryland wheat agroecosystem
Get PDFBiosolids land application for beneficial reuse applies varying
amounts of trace metals to soils. Measuring plant-available or
total soil metals is typically performed to ensure environmental
protection, but these techniques do not quantify which
soil phases play important roles in terms of metal release or
attenuation. This study assessed the distribution of Cd, Cr,
Cu, Mo, Ni, Pb, and Zn associated with soluble/exchangeable,
specifically adsorbed/carbonate-bound, amorphous Mn
hydroxyoxide-bound, amorphous Fe hydroxyoxide–bound,
organically complexed, and residual inorganic phases. Biosolids
were applied every 2 yr from 1982 to 2002 (except in 1998)
at rates of 0, 6.7, 13.4, 26.8, and 40.3 dry Mg biosolids ha−1
to 3.6- by 17.1-m plots. In 2003, 0- to 20-cm and 20- to
60-cm soil depths were collected and subjected to 4 mol L−1
HNO3 digestion and sequential extraction. Trace metals were
concentrated in the 0- to 20-cm depth, with no significant
observable downward movement using 4 mol L−1 HNO3 or
sequential extraction. The sequential extraction showed nearly
all measurable Cd present in relatively mobile forms and Cr,
Cu, Mo, Ni, Pb, and Zn present in more resistant phases.
Biosolids application did not affect Cd or Cr fractionation
but did increase relatively immobile Cu, Mo, and Zn phases
and relatively mobile Cu, Ni, and Pb pools. The mobile
phases have not contributed to significant downward metal
movement. Long-term, repeated biosolids applications at rates
considered several times greater than agronomic levels should
not significantly contribute to downward metal transport and
ground water contamination for soils under similar climatic
conditions, agronomic practices, and histories
Whey utilization in furrow irrigation: Effects on aggregate stability and erosion
Get PDFImproving soil structure often reduces furrow erosion and maintains adequate infiltration. Cottage
cheese whey, the liquid byproduct from cottage cheese manufacture, was utilized to stabilize soil aggregates
and reduce sediment losses from furrow irrigation. We applied either 2.4 or 1.9 L of whey per meter
of furrow (3.15 or 2.49 L m�-2, respectively) by gravity flow without incorporation to two fields of Portneuf
silt loam (Durinodic Xeric Haplocalcid) near Kimberly, ID. Furrows were irrigated with water beginning
four days later. We measured sediment losses with furrow flumes during each irrigation and
measured aggregate stability by wet sieving about 10 days after the last irrigation. Overall, whey significantly
increased aggregate stability 25% at the 0–15 mm depth and 14% at 15–30 mm, compared to controls.
On average, whey reduced sediment losses by 75% from furrows sloped at 2.4%. Whey increased the
aggregate stability of structurally degraded calcareous soil in irrigation furrows
The characterization of trace metals and organics in spent foundry sands over a one-year period
Get PDFMillions of tons of spent sand, used to create metal casting molds, are generated
by the foundry industry each year in the United States. Not surprisingly, spent
foundry sands (SFSs) are an excellent substitute for virgin sands that are currently used
in manufactured soils and geotechnical applications. The purpose of this study was to
characterize trace metals and EPA-priority polycyclic aromatic hydrocarbons (PAHs)
and phenolics in ferrous and non-ferrous SFSs over a one-year period. Overall, the total
metal concentrations in the SFSs were similar to those found in native soils, while the
PAHs and phenolic concentrations were relatively low. Metal leaching tests were also
performed, which revealed that the SFSs have a low metal leaching potential under the
specific test conditions. The data from this study suggests that the majority of SFSs are
not hazardous in nature, except those that use olivine sands or are from brass foundries,
due to the presence of elevated concentrations of Ni or Cu, Pb, and Zn, respectively. This
information will be useful to environmental regulators who are considering including
SFSs in their beneficial use regulations
Evaluation of phosphorus characterization in broiler ileal digesta, manure, and litter samples: 31P-NMR vs. HPLC
Get PDFUsing 31-phosphorus nuclear magnetic resonance spectroscopy ((31)P-NMR) to characterize phosphorus (P) in animal manures and litter has become a popular technique in the area of nutrient management. To date, there has been no published work evaluating P quantification in manure/litter samples with (31)P-NMR compared to other accepted methods such as high performance liquid chromatography (HPLC). To evaluate the use of (31)P-NMR to quantify myo-inositol hexakisphosphate (phytate) in ileal digesta, manure, and litter from broilers, we compared results obtained from both (31)P-NMR and a more traditional HPLC method. The quantification of phytate in all samples was very consistent between the two methods, with linear regressions having slopes ranging from 0.94 to 1.07 and r(2) values of 0.84 to 0.98. We compared the concentration of total monoester P determined with (31)P-NMR with the total inositol P content determined with HPLC and found a strong linear relationship between the two measurements having slopes ranging from 0.91 to 1.08 and r(2) values of 0.73 to 0.95. This suggests that (31)P-NMR is a very reliable method for quantifying P compounds in manure/litter samples
Sugar beet cultivars evaluated for storability in Idaho during the 2006/2007 storage season
Get PDFThirty-two commercial sugar beet cultivars were grown in a commercial sprinkler-irrigated sugar beet field near Nampa, ID. The previous crop was corn. The plots were planted on 27 and 28 Mar 2006 to a density of 142,560 seeds/A, and thinned to 47,520 plants/A on 10 and 11 May. Plots were four rows (22-in. row spacing) wide and 34.5 ft long. The experimental design was a randomized complete block with four replications per cultivar. The crop was managed by the grower according to standard cultural practices. Eight roots per plot were hand dug from an outside row and topped on 12 Oct and placed into nylon mesh onion bags. The roots were then weighed and placed on top of an indoor commercial sugarbeet storage pile in Paul, ID which was set to hold 36°F. The plants in the center two rows were mechanically topped and yield data was collected with a mechanical harvester on 17 Oct. The percent sugar at harvest was established based on two 8-beet samples submitted to the Amalgamated Tare Lab (determined percent sugar, conductivity, nitrates, and tare). On Mar 2007 (144 days since harvest), the roots were retrieved from storage and evaluated for root rot (percentage of root surface area covered with fungal growth or discolored), weight, and percent sugar (via gas chromatography). To establish percent reduction in sugar at harvest versus storage, only samples from the same plot were compared. Data were analyzed using the general linear models procedure (Proc GLM-SAS), and Fisher's protected least significant difference was used for mean comparisons.
The field trial was disease free except for a trace amount of curly top. Yields for this production area in 2006 and the plot area were both above average. Cultivars differed for root yield and estimated recoverable sugar (ERS) at harvest and for surface rot (isolations revealed a diversity of fungi) after being in storage. Cultivars coming out of storage did not differ for weight reduction. Sugar reduction ranged from 16 to 40% and ERS ranged from 13,300 to 8,449 lb/A after storage differences between cultivars could not be proven. With regression analysis, ERS after storage was best explained by surface rot (r2 = 0.32, P < 0.0001) and to lesser extent with weight reduction (r2 = 0.24, P < 0.0001), and nitrates (r2 = 0.1= 0.0001), percent sugar (r2 = 0.05, P = 0.0088), and conductivity (r2 = 0.04, P = 0.0150) in roots at harvest. Given the ranges in ERS after storage, there would appear to be potential for improving storability in cultivars, but better selection criteria must be established. In order to establish better criteria, either more replications should be considered and/or conditions that allow for greater separation based on ERS after storage must be found
Polyacrylamide treatments for reducing seepage in soil-lined reservoirs: A field evaluation
Get PDFIrrigation water supplies are becoming limited, and there is a need to extend the usefulness of current water resources. Previous laboratory studies demonstrated that certain water-soluble polyacrylamide solution (WSPAM) and cross-linked PAM granule (XPAM) treatments effectively reduced infiltration into soils. We evaluated the efficacy of these treatments for reducing water seepage losses in an unlined irrigation reservoir. Five treatments were applied to plots on the lower side slopes of a reservoir basin before it was filled in April 2001: controls; 0.016 kg m -2 WSPAM (1000 mg L -1 solution); 0.2 kg m -2 XPAM + 0.13 kg m -2 NaCl; 0.4 kg m -2 XPAM + 0.13 kg m -2 NaCl; and 0.8 kg m -2 XPAM only. Ring-cylinder seepage meters installed in each experimental plot were used to monitored seepage rates from May through October in 2001 and 2002, without further treatment applications. The WSPAM and XPAM treatments were equally effective for reducing pond seepage in 2002 but not 2001. On average, they reduced mean seepage rates an average 50% relative to the 22.4 mm h -1 control value and prevented the loss of 19.7 m of water through the seepage rings over the two irrigation seasons. The 0.016 kg m -2 WSPAM and 0.2 kg m -2 XPAM + 0.13 kg m -2 NaCl treatments are most cost effective, but the greater XPAM rates appeared to be the most durable treatments, since they retained their efficacy through the end of the second irrigation season. Results are consistent with a previous study suggesting that adding NaCl to XPAM treatments reduced required XPAM inputs without reducing treatment efficacy. The WSPAM and XPAM treatments provide several effective options for reducing seepage losses in earthen reservoirs
Transgenic sugar beet cultivars evaluated for resistance to bacterial root rot in Idaho, 2007
Get PDFThirty-three transgenic (glyphosate resistant) sugar beet cultivars were grown in a commercial sprinkler-irrigated
sugar beet field near American Falls, ID where potatoes were grown in 2006. The plots were planted on 30 Apr to a density
of 352,272 seeds/ha, and thinned to 88,068 plants/ha on 12 Jun. Plots were four rows (0.56-m row spacing) and 10.5 m long.
The experimental design was a randomized complete block design with eight replications. The crop was managed according
to standard cultural practices. The field trial was free of foliar and root disease symptoms. Four roots from one plot for each
cultivar from the same replication were hand topped and harvested on 1 Oct. The roots were then placed in a cold room at
3°C and 90% relative humidity until they were assayed on 3 Feb 08. The roots were washed, dipped in 0.6% sodium
hypochlorite solution for 1 min, rinsed in sterile reverse osmosis water, and then air dried in a laminar hood. A cross section
from the middle of the root 8-10 mm thick and 45 to 70 mm in diameter was cut from each root and placed in a Petri dish on
sterile filter paper moistened with sterile well water. A 2 mm diameter and 3 mm deep hole was created with a sterile tooth
pick in the center of the root slice. A sterile tooth pick was then dipped in a 48 hr old culture of Leuconostoc mesenteroides
subsp. dextranicum B322 grown on MRS media at 30°C and placed in the hole along with a drop of sterile well water. Four
additional root slices from HM090026 served as the uninoculated check (no bacteria inoculated). The root slice/Petri dish
combination was placed in a plastic bag and incubated at 30°C. The experiment was a randomized complete block design
with 4 replications (1 root slice = 1 replication for each cultivar). The diameter of rotted root area was recorded after 72 and
96 hr. Bacteria from the 10 largest lesions in each replication were streaked onto MRS to prove only L. mesenteroides was
present. Data were analyzed using the general linear models procedure (Proc GLM-SAS), and Fisher’s protected least
significant difference was used for mean comparisons
Evaluation of strip-tillage and fertilizer placement in Southern Idaho corn production
Get PDFStrip tillage (ST) and associated nutrient placement can potentially help producers reduce fuel
and machinery costs, increase yield, and reduce soil erosion compared to chisel tillage (CT).
This study was initiated to evaluate corn production (Zea mays L.) under ST and CT, and various
nitrogen (N) and phosphorus (P) fertilizer placements. The effects of tillage practice and N and
P placement on grain and biomass yield of field corn was assessed on two sites at the USDA ARS
Northwest Irrigation & Soils Research Laboratory at Kimberly, ID with different levels of
soil fertility and productivity. Two sites were selected in a furrow irrigated field that had been
previously cropped to alfalfa. Site A was located in the top half of the field and Site B was
located in the bottom half of the field. Site A had lower levels of soil organic C (OC) and soil
test P and K compared to Site B. The treatments were 1) ST with deep placement of N and
broadcast P; 2) ST with 2 by 2 placement of N and broadcast P; 3) ST with deep placement of N
and P; 4) CT with 2 by 2 placement of N and broadcast P; and 5) CT with broadcast N and P.
The grain yields at Site A were greater for ST compared to CT. The deep band placement of N
and P with ST had a yield (175 bu acre-1) advantage of 23 and 16 bu acre-1 over both CT
treatments, respectively and increased yields to levels similar to the average of Site B (178 bu
acre-1). No differences in grain yield occurred at Site B for all treatments. There were no
differences in biomass yield of corn at the VT (tassel) growth stage and grain harvest time at
both sites. The average total dry matter biomass at grain harvest time was 9.1 and 10.4 tons acre-1
averaged over all treatments, respectively. Data from year one of this study indicates that ST and
deep band placement of N and P increased corn grain yield over CT and conventional fertilizer
placement methods in highly eroded low fertile soils. Irrespective of the potential yield increases
there may be an economic advantage associated less fuel due to less tillage passages with ST
compared to CT. Because the data presented in this paper is from one year, caution should be
exercised in extrapolating these results from year to year due to the variability in crop production
associated with time-specific factors. This study will be carried out over a least one to two more
years before final conclusions and recommendations are issued
Revegetation of Fluvial Mine Tailing Deposits: The Use of Five Riparian Shrub Species
Get PDFFluvial deposition of mine tailings has caused extensive damage to riparian ecosystems throughout the West. Willows are often used for revegetation of fluvial mine tailing deposits but some species accumulate toxic concentrations of metals in leaves and stems. A greenhouse experiment was conducted to determine the value of thinleaf alder [Alnus incana (L.) Moench spp. tinuifolia (Nutt.) Breitung], water birch (Betula occidentalis Hook.), red osier dogwood (Cornus sericea L. spp. sericea), and shrubby cinquefoil [Dasiphora fruticosa (L.) Rybd.] compared to Geyer willow (Salix geyeriana Andersson) for revegetation of fluvial tailing deposits along the Upper Arkansas River. Bare root shrubs were grown in tailings amended with lime and composted biosolids. Tailings were collected from three acidic and metal contaminated deposits along the Arkansas River south of Leadville, Colorado. All shrubs survived the two month experiment. Averaged across source deposits, total biomass during the experiment increased for alder, birch, dogwood, cinquefoil, and willow by 831, 689, 579, 525, and 683%, respectively. All species concentrated Pb and Zn belowground. Dogwood assimilated little Zn (44.0 mg kg-1) into its leaves and stems, but showed signs of nutrient deficiency which could have been induced by metal stress. Alder and cinquefoil partitioned Pb aboveground, 30.3 and 26.1 mg kg-1, respectively, which is unusual, but concentrations were below toxicity thresholds for humans and animals. All species evaluated did not exhibit greater growth when compared to Geyer willow, but the other four riparian species had metal partitioning characteristics valuable for managers planning for in situ restoration of mine tailing deposits
Decomposition of Bt and non-Bt corn hybrid residues in the field. Nutrient Cycling in Agroecosystems
Get PDFResults of a previous laboratory study indicated that six transgenic crops expressing the Cry1Ab insecticidal protein from Bacillus thuringiensis (Bt) decomposed at a slower rate than their respective non-Bt isolines. Consequently, litter decomposition rates, nitrogen cycling, and carbon pools may change in agricultural systems as the result of the widespread use of Bt crops. In this study, we assessed the decomposition rates and chemical composition of commonly grown hybrids of Bt and non-Bt isolines of corn (Zea mays L.) in the field. Leaves, stalks, and cobs from two Bt corn hybrids (Pioneer 34N44 Bt and NC+ 4990 Bt) and their non-Bt isolines (Pioneer 34N43 and NC+ 4880) were analyzed for biomass fractions (soluble, hemicellulose, cellulose, and lignin) and total C and N content. Litterbags containing these residues were buried at a depth of 10 cm in a Holdrege silt loam (fine-silty, mixed, mesic Typic Argiustolls) soil and recovered 5, 11, 17, and 23 months after placement in the field. There were no differences in the rates of decomposition and mass of C remaining over time between the Bt and non-Bt corn residues. Plant parts differed in decomposition rates where leaves > stalks > cobs. There were differences in total C, total N, biomass fractions, and C:N ratios between initial Bt and non-Bt corn residues, and between companies (NC+ and Pioneer), however, these differences did not result in differences in their rates of decomposition or mass of C remaining over time. For each plant part, there were no differences in lignin content between the Bt and non-Bt residues. These data suggest that the Bt and non-Bt corn hybrids used in this study should not cause differences in carbon sequestration when their residues decompose under similar environmental conditions