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Removing soluble phosphorus in irrigation return flows with alum additions
Get PDFABSTRACT: Phosphorus (P) losses from irrigated cropland transferred to surface waters via
irrigation return flows, can impair regional water quality. Best management practices to reduce
soil erosion on fields and sediment concentration in return flows do little to reduce soluble P
concentrations, which can exceed total maximum daily load (TMDL) limits for total P. Laboratory
and field tests were conducted to evaluate the effect of alum on soluble P concentration in return
flow water from an irrigation tract in southern Idaho. The laboratory study used two water
sources (tap and irrigation), three sediment concentrations (0, 100 and 1000 mg L-1), two added
P concentrations (0 and 1 mg L-1), and five alum concentrations (0, 5, 10, 20 and 40 mg L-1). Field
tests were conducted at sediment ponds on two irrigation drains with 20 to 500 mg L-1 sediment
and 0.09 to 0.19 mg L-1 dissolved P in inflow water. Regression analysis of laboratory data
showed a 53 percent reduction in soluble P concentration with 20 mg L-1 alum, which was similar
to field data. Applying 40 mg L-1 alum to irrigation water reduced soluble P concentrations up to
98 percent in the field. Achieving 50 percent soluble P reduction would cost about 8.25 per ac ft) at the current alum cost of 0.15 lb-1). Although alum effectively
reduced soluble P in irrigation return flow, the cost of applying alum may be too high for routine
use in many irrigation districts
Application rates from center pivot irrigation with current sprinkler types
Get PDFCenter pivot sprinkler irrigation is increasing in popularity in the United States due to the low labor requirement
and ability to irrigate large fields. The main problem associated with pivots continues to be the inherently high application
rates and tendency for runoff and erosion on medium- and fine-textured soils and rolling topography. Recently developed
sprinklers or spray heads can produce high application uniformity with controlled drop sizes and medium sized pattern widths
at medium to low pressures. A method is presented to predict the average and peak application rates at any point along a center
pivot lateral for a particular type of sprinkler. The method can be incorporated with infiltration and center pivot design models
to predict when runoff might occur. A computer program is available to aid in the design process and compare alternative
configurations
Sediment pond effectiveness for removing phosphorus from PAM-treated irrigation furrows
Get PDFPolyacrylamide (PAM) greatly reduces erosion on furrow-irrigated fields and sediment ponds can be constructed
to remove suspended sediment from irrigation runoff. Both practices are approved for reducing phosphorus (P) loading in
the Lower Boise River Pollution Trading Project in southwest Idaho, but information is not available about using both
practices on the same field. The objective of this study was to measure the combined effects of PAM application and sediment
ponds on sediment and P losses from a furrow-irrigated field. Small sediment ponds (5.8 m 2) with a 60-min design retention
time were installed on two fields to receive runoff from PAM-treated or control furrows. Pond inflow and outflow were
monitored during a total of 11 irrigations on the two fields. Three crop years of data showed that applying PAM to furrows
reduced sediment and total P mass transport to the ponds 50% to 80%, which reduced the mass of sediment and total P retained
in the ponds. However, PAM application did not change the percentage of sediment (86%) and total P (66%) retained. The
PAM-sediment pond combination reduced average total P loss by 86% to 98%, based on the difference between untreated
inflow and PAM-treated outflow. PAM and sediment ponds had little or no effect on dissolved reactive P (DRP)
concentrations. The mass of DRP retained in sediment ponds was directly related to the amount of water that infiltrated within
the ponds. Applying PAM to irrigation furrows and installing sediment ponds at the end of the field can be an effective
combination for reducing sediment and total phosphorus losses from furrow-irrigated fields, but these practices only reduced
soluble P losses by decreasing the volume of water that ran off the fields
Polymer and sprinkler droplet energy effects on sugar beet emergence, soil penetration resistance, and aggregate stability
Get PDFPolymers in water applied to soil surfaces may increase aggregate stability and reduce aggregate slaking,
thus minimizing crusting and increasing sugar beet (Beta vulgaris L.) emergence. We studied a cationic
organic polymer, Nalcolyte 8102, manufactured by Ondeo Nalco Co., Naperville, IL, USA. The
material's active ingredient is a poly diallyldimethyl ammonium chloride (polyDADMAC), a proprietary
quaternary polyamine. Surface-applied Nalcolyte 8102 and droplet energy were evaluated in laboratory
and field studies for their effects on sugar beet emergence, soil penetration resistance (PR), and
aggregate stability of two sprinkler irrigated, crust-prone silt loams in Idaho, U.S.A. In the laboratory,
Nalcolyte 8102 at 1.1 Mg active ingredient (a.i.) ha -1 was applied in 74,000 L of solution ha-1 of wetted
area; 5.4 Mg a.i. ha-1 was applied in both 50,000 and 105,000 L ha -1 ; and untreated water at
49,000 L ha-1 was applied as a control. These treatments applied a. 7 mm (7 mm3 mm-2) of a 5% by
volume solution, 5 mm of a 37% solution, a. 10 mm of an 18% solution, and a. 5 mm of untreated
water, respectively. Later, at three field sites, Nalcolyte 8102 at 0.7 and 1.1 Mg a.i. ha -1 were each
applied in 74,000 L ha-1 of solution (a. 7 mm of a 3 and 5% solution, respectively) by spraying at
planting onto two soils, a Durinodic Xeric Haplocalcid and a Xeric Haplodurid, with sugar beet
planted to stand. In the laboratory, Nalcolyte 8102 at 1.1 Mg ha -1 increased emergence 2.5-fold (32%
to 80%) and reduced PR 3.5-fold (1.34 MPa to 0.39 MPa) at 22 days after planting (DAP), compared
with controls. In the field, 0.7 and 1.1 Mg ha -1 increased emergence 1.2-fold (48.4 to about 58.3%) 50
DAP and increased aggregate stability after treatment 1.4-fold (68% to 97%) one DAP and 1.2-fold
(76% to about 89%) 50 DAP, relative to an untreated control that received no water
Pathogenicity and real-time PCR detection of Fusarium spp. in wheat and barley roots
Get PDFThe pathogenicity of five Fusarium spp. frequently isolated from wheat and barley roots in southern Idaho
was investigated during four growth-chamber experiments and two field studies. A real-time PCR assay for quantifying
the presence of E culmorum from infected root tissue was also developed based on nucleotide sequence for the tri5
gene. Fusarium culmorum, followed by E acuminatum and E reticulatum, resulted in the largest root lesions and
percent infected root area. However, E semitectum, followed by E acuminatum and E equiseti, had the greatest impact
on total root length. The TaqMan-based real-time assay was able to quantify E culmorum in root tissue from both
growth-chamber and field studies down to 61 pg. The assay also detected E pseudograminearum and E graminearum
but could not distinguish among these three Fusarium sp
Phosphorus availability to barley from manures and fertilizers on a calcareous soil
Get PDFHigh concentrations of animal production in the United States have
increased the concern about the environmental fate of phosphorus (P) in
manures. We conducted a growth chamber study to develop phosphorus
source coefficients (PSCs) for manures and fertilizers typically land applied
and incorporated into calcareous soils of the western United States
as well as to determine the potential plant P availability of these sources.
Six manure types (swine solids from low phytate and regular barley diets,
swine liquid, dairy liquid, beef solid, and dairy compost) and four fertilizer
(mono calcium phosphate, mono ammonium phosphate, polymer-coated
mono ammonium phosphate, and ammonium polyphosphate) P
amendments were applied to two Portneuf soils at a rate of 60 mg P
kg -1 , incubated for 2 weeks, then planted with barley grown for 7 weeks.
Soil samples were analyzed before barley planting and then at 4 and 7
weeks after planting, whereas plant samples were analyzed at 4 and 7
weeks. Increases in soil water soluble (WS-P) and bicarbonate P (Olsen
P) from P additions generally followed the pattern [fertilizer P] > {liquid
manures] > [solid or composted manures]. Plant shoot biomass and plant
P accumulation were similar except swine manures were greater than
inorganic P sources and beef manure was less than both. Determining
relative P solubility of manure and fertilizer sources will be beneficial
when estimating P losses from land application of manures and may be
used to assign weighting coefficients to manure sources in risk assessments
such as a P site index, with limited impact on P availability to
crops
Identification and mapping of markers linked to the Mi Gene for root-knot nematode resistance in peach
Get PDFAn F2 population from a single F1 plant from the cross of peach [Prunuspersica (L.) Batsch] rootstock cultivars
Harrow Blood (HB) x Okinawa (Oki) was used to locate the Mi locus, which conditions resistance to Meloidogyne incognita (race 1) (Kofoid and White) Chitwood. These data and comparison of common markers among published genetic
linkage maps placed the Mi locus on Prunus L. linkage group 2. Two restriction fragment length polymorphisms (RFLPs)
[linked at 4.8 and 6.8 centimorgan (cM), repulsion phase] and one random amplified polymorphic DNA (RAPD) marker
(linked at 9.5 cM, coupling phase) were linked to Mi. The RAPD marker was cloned, sequenced, and converted to a
polymerase chain reaction (PCR)-based cleaved amplified polymorphic sequence (CAPS) marker. Clones of resistance
gene analogs (RGA) developed from Oki were highly polymorphic when used as RFLP probes. The RGA’s mapped to
four linkage groups but clustered on two of the four linkage groups, providing limited coverage of the genome. Even
so, they may be useful as markers for disease resistance genes that occur in other populations. The linkage maps of
the HB x Oki F2 population and a peach x almond (Prunus amygdalus Batsch) F2 population were colinear in certain
regions, however, a significant number of markers mapped to different linkage groups among the two populations. The
locus for the blood-flesh trait (red-Violet mesocarp) mapped to the top of linkage group 4
Balancing the phosphorus budget of a swine farm: A case study
Get PDFTrends in animal production have moved the industry toward
large confined animal feeding operations (CAFOs). These
CAFOs concentrate large amounts of manure-based nutrients
in relatively small areas, which increases the risk of nutrient loss
to the surrounding environment. In response to water quality
concerns, P-based manure application regulations are becoming
more common. Mr. Pritchard is the owner and operator of
two 4500-head swine (Sus scrofa) farms located in an area of intensive
animal production in North Carolina. He has noticed an
increasing trend in the soil P concentrations in his manure application
fields and realizes that he does not have enough land
to apply his anaerobically treated liquid swine manure based
on crop P uptake. Mr. Pritchard is now faced with the dilemma
of what to do to slow down the P accumulation in his soil. This
case constructs a P budget for Mr. Pritchard's farm to examine
ways of balancing on-farm nutrients. Students are encouraged
to explore solutions related to animal nutrition, crop production,
water quality, soil chemistry, and manure management.
Furthermore, students should evaluate the appropriate role of
government and industry in assisting Mr. Pritchard to protect
the environment while remaining a profitable swine producer
Dry matter uptake and digestion of alfalfa harvested at sunset and sunrise
Get PDFThe preference exhibited by animals in selecting one feed over another is important only if the preferred diet is consumed daily in larger quantities, digested to a greater extent, or both. Six alfalfa (Medicago sativa L.) hays were harvested in pairs at sunset (PM) and sunrise (AM) on consecutive days at three harvest dates. A previous study of these hays demonstrated differences in ruminant preference favoring PM harvests. This study evaluated the effects of time of cutting and harvest date on voluntary DMI and nutrient digestibility. The hays were field-cured, baled, and chopped before evaluation for intake and digestibility. Studies were conducted for sheep (Ovis aries), goats (Capra hircus), and cattle (Bos taurus). Goats, but not steers or sheep, demonstrated differences in nutrient digestibility between PM- and AM-cut hays. Goats consumed more PM than AM hay (2.97 vs. 2.83 kg/100 kg of BW; P = 0.07) and digested it to a greater extent (0.710 vs. 0.696; P = 0.03), resulting in greater digestible DMI (2.11 vs. 1.97 kg/100 kg of BW; P = 0.03). Sheep consumed (mean = 2.52 kg/100 kg of BW; P = 0.59) and digested (mean = 0.681; P = 0.25) PM- and AM-cut hays similarly. Steers consumed larger quantities of PM-than AM-cut hay (2.90 vs. 2.62 kg/100 kg of BW; P = 0.11), but digestion did not differ with cutting time (mean = 0.660; P = 0.75). Difference values (composition of fed hay minus composition of orts) indicated that sheep and goats selected from the feed offered similarly, whereas steers selected differently. Difference values for CP averaged 94 and 101 g/kg for goats and sheep and 32 g/kg for steers (P < 0.01), and difference values for NDF averaged 185 and 196 g/kg for goats and sheep and 73 g/kg for steers (P <or= 0.01). Steer DMI and digestible DMI were associated with preference (r = +0.83, P <or= 0.05; and r = +0.89, P <or= 0.05) and with coordinates for preference criteria (dimension 1; r = +0.90, P <or= 0.05; and r = +0.89, P <or= 0.05) from a previous preference trial. Intake and digestion responses for goats and sheep showed no relationship with the previous preference trial measurements. For cattle and goats, the management strategy of mowing in the afternoon seems to take advantage of small, but influential diurnal changes in the soluble carbohydrate fraction and offers the potential to improve forage quality
Russian wildrye nutritive quality as affected by accession and environment
Get PDFHigh-quality forage for spring and fall grazing is an important need of ranchers
in the Northern Great Plains and Intermountain-West regions of the United States of America and in the prairie provinces of Canada.
Russian wildrye [Psathyrostachys juncea (Fischer) Nevski] has been used to meet this grazing need, especially in Canada. However, its
use has probably been limited by its reputation for seedling establishment difficulties and scattered reports of grass tetany. The purpose
of this research was to characterize the variation in nutritive quality of Russian wildrye accessions used in a multi-location grass tetany
project, to access the effect of environment on quality components, and to determine the relationship between forage nutritive quality
components and entities associated with grass tetany. Sixty-seven Russian wildrye accessions from the US National Plant Germplasm
System were established in spaced-plant nurseries at Logan,UT, Mandan, ND, and Swift Current, SI(, Canada. Plants were sampled at
two stages of development over 2 yr. Location, year, and stage of development effects were significant (P < 0.01) for in vitro true dry
matter digestibility (IVDMD), crude protein (CP), and neutral detergent fiber (NDF). At the early stages of development used in this
study the range in nutritive quality traits among entries was rather narrow. Relatively high positive correlation coefficients between K
and IVDMD, and K and CP suggest that breeding for higher nutritive quality may also produce a more tetany-prone forage, because high
K concentration is usually associated with grass tetany. On the other hand, Mg concentrations were also highly correlated with IVDMD
and CP, and higher Mg concentrations would be beneficial in preventing grass tetany. The K/(Mg + Ca) ratio, which has been suggested
as an indicator of grass tetany, was only moderately related to IVDMD, CP, and NDF