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Soil genesis and development, lesson 4: Soil profile development
Get PDFThe processes occurring over time in a soil are
reflected in vertical and lateral physical and chemical characteristics
of that soil. The four soil forming processes, in
conjunction with the five factors of soil formation, organize
parent material into a soil profile that consists of soil horizons.
These processes can occur over millennia; however,
they can also be influenced by short-term variables such as
human use. Understanding the processes enables interpretation
of the natural history of a soil and provides a
starting point to evaluate how future changes will affect the
soil resource. Combining landscape history with knowledge
of principles of soil profile development allows for more
precise and effective land use planning, from residential
development to precision agricultural practices.
At the completion of this lesson, students will be able to do
the following:
1. Describe the four major soil forming processes.
2. Describe how these four processes redistribute soil
materials in vertical and horizontal dimensions.
3. Explain which soil processes are dominant in each
soil horizon.
4. Develop a profile horizon sequence based on given
soil properties and a set of soil forming factors
5. Describe the general soil forming processes based
on the soil forming factors that led to the development
of a given soil profile.
The lesson is written to target educational needs of lower-level
undergraduate students and is open for use by the
public and educational institutions
Soil genesis and development, lesson 5: Soil classification and geography
Get PDFThe system of soil classification developed by the
United States Department of Agriculture (USDA) is called
Soil Taxonomy. This lesson focuses on broad descriptions of
soils at the Order level of classification.
At the completion of this lesson, students will be able to do
the following:
1. Describe the structure of the USDA soil taxonomic
system.
2. Describe the defining characteristic(s) of each of the
12 soil Orders.
3. Apply the concept of soil forming factors to the formation
and occurrence of each of the 12 soil Orders.
4. Identify regional scale occurrences of soil orders in
the USA.
The lesson is written to target educational needs of lowerlevel
undergraduate students and is open for use by the
public and educational institutions
Commercial sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2008
Get PDFEighteen commercial sugar beet cultivars were evaluated in a commercial sprinkler-irrigated sugar beet field near
Jerome, ID where winter wheat was grown in 2007. The field trial relied on natural infection for rhizomania development.
The plots were planted on 22 Apr 08 to a density of 142,560 seeds/A, and thinned to 47,520 plants/A on 30 May. Plots were
four rows (22-in. row spacing) and 34.5 ft long. The experimental design was a randomized complete block design with four
replications per cultivar. The crop was managed according to standard cultural practices. The roots were mechanically
topped and the center two rows were collected with a mechanical harvester on 9 Oct. At harvest the roots were evaluated for
rhizomania (Rz rating) using a scale of 0-9 (0 = healthy and 9 = dead). The percent sucrose at harvest was established based
on two eight-root samples from each plot. The samples were submitted to the Amalgamated Tare Lab (determined percent
sucrose, conductivity, nitrates, and tare). At harvest, eight roots per plot were also placed in a mesh onion bag, weighed, and
placed in an indoor commercial sugar beet storage facility on 9 Oct set to hold 35°F. On 29 Jan 09, the roots were evaluated
for the percentage of surface area covered by fungal growth (an undescribed basidiomycete that correlates with sucrose loss
in storage). On 2 Feb 09 roots were retrieved after 115 days in storage and evaluated for weight and percent sucrose (via gas
chromatography). To establish percent reduction in sucrose at harvest versus storage only samples from the same plots 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.
Rhizomania was uniform throughout the plot area. Root rots and other disease problems were not evident in the
plot area. Root yield averaged 44 tons/A which was higher than Idaho’s average of 31 tons/A (USDA-National Ag. Stat.
Service). There were significant differences among cultivars for all variables except Rz rating and weight reduction. All
cultivars possessed at least the Rz1 gene for resistance to Beet necrotic yellow vein virus, so finding no differences for the Rz
rating was not surprising. Surface fungal growth got started in Nov 08 and ranged from 7 to 75% by 29 Jan 09 depending on
cultivar. By the end of the storage season, sucrose losses ranged from 45 to 66%. Thus, improving storability in sugar beet
cultivars to reduce sucrose losses could have considerable economic benefit
Spatially distributed control netowork for flow proportional chemical injection with center pivot irrigation
Get PDFThe agricultural production practice of injecting a chemical into an operating irrigation system and applying it
to the field area with the water is known as chemigation. Chemigation is a widely adopted practice with center pivot sprinkler
irrigation. However, the practice of chemical injection at a constant rate with center pivot sprinkler irrigation systems
equipped with an end gun and/or swing‐arm corner watering system results in systematic chemical application errors ranging
from 7% to 21% due to systematic changes in system flow rate. Chemical injection proportional to center pivot sprinkler
system flow rate is one approach to reduce systematic chemical application errors. The objective of this project was to test
the feasibility of using real‐time monitoring of center pivot sprinkler irrigation system operating status to control chemical
injection rate proportional to calculated system flow rate, thus minimizing systematic chemical application errors. A spatially
distributed control network was developed to facilitate real‐time monitoring of end gun and swing‐arm corner watering
system operating status and pressure. The spatially distributed control network consisted of three network nodes at specific
locations along a center pivot sprinkler irrigation lateral that used the 480 VAC 3‐phase power cable on the center pivot
sprinkler irrigation system as the communication medium. The spatially distributed control network was installed on a
commercial 460‐m (1510‐ft) long center pivot sprinkler system equipped with an end gun and swing‐arm corner watering
system. Performance of chemical injection proportional to calculated flow rate based on real‐time center pivot sprinkler
irrigation system operating status was evaluated by injecting Rhodamine WT dye into the center pivot sprinkler irrigation
system water supply and measuring its concentration in the applied water. Mean dye concentration varied by 26% under
constant rate chemical injection and 2% under flow proportional chemical injection due to systematic changes in center pivot
sprinkler irrigation system flow rate. Use of the flow proportional chemical injection system reduced the coefficient of
variability in measured dye concentration of applied water by 54% from 0.100 to 0.046. Use of the spatially distributed control
network for calculating center pivot sprinkler system flow rate eliminates the need for straight sections of unobstructed piping
at the chemical injection site. Display and/or data logging of real‐time center pivot sprinkler operating status is an added
benefit of using the spatially distributed control network. This information provides the ability to monitor, diagnose, and
troubleshoot center pivot sprinkler system operation. Commercialization and adoption of the technology could reduce
systematic chemical application errors and facilitate maintenance and operation of center pivot sprinkler irrigation systems
equipped with an end gun and/or swing‐arm corner watering system
Phosphorus mobility in soil columns treated with dairy manures and commercial fertilizer
Get PDFThe concentration of animal production in some areas of the United States has led to concern about the environmental fate of manure-derived phosphorus (P) in soils. A column study was conducted to quantify P leaching in a calcareous soil treated with monoammonium phosphate (MAP), two solid dairy manures (D1S and D2S), and two liquid dairy manures (D1L and D2L). A control with no P application was also included. Treatments were applied at 166 kg P ha-1 to columns packed with 20 cm of a Warden fine sandy loam (coarse-loamy, mixed superactive, mesic Xeric Haplocalcids) in a completely randomized design with four replications and housed in a climate-controlled growth chamber. Simulated irrigation water was added to the columns at a rate of 47.4 mm (450 mL) during 13 events during a 9-week period, with leachate collected, volume recorded, and concentrations of total organic carbon (TOC) and total P (TP) determined for each event. At the end of the leaching events, each soil column was divided into eight 2.5-cm segments. Then, soil was air-dried, ground, and analyzed for TP, total carbon, calcium (Ca), iron, and manganese, and water-soluble P. The masses of TP and TOC in leachate were in the order D1L=D2L > MAP=D1S=D2S=Control. There was a positive linear relationship between the cumulative mass of TOC and cumulative mass of TP lost in leachate over all manure treatments (r2=0.98). The masses of TP and water-soluble P for treatments in the entire soil columns were in the order MAP > D1L=D2L > D1S=D2S=Control. Masses of P and C in leachate and soil show that P mobility in soil was in the order liquid dairy manures > MAP > solid dairy manures. At the end of the study, the total C was greater in the surface 2.5 cm of the soil columns for the solid manure treatments compared with the other treatments/depth combinations. The greater leaching of P in the liquid manure treatments compared with the solid manure treatments may be caused by a combination of factors including microbial activity, organically complexed metals, coating of P adsorption sites on clay particles by organic C compounds, and P-Ca and P-aluminum reactions
Sugar beet root rot at harvest in the US Intermountain West
Get PDFRoot rot in sugar beet (Beta vulgaris) causes significant losses worldwide. To assess the distribution of root
rot fungi and their relationship to bacterial root rot,commercial sugarbeet roots with rot symptoms were collected at
harvest time in the Intermountain West. Isolations for both fungi and bacteria were conducted using standard
microbiological techniques, and the root area rotted was assessed. A subset of fungal isolates was tested for
pathogenicity to sugar beet in greenhouse assays and field trials with and without manure. In the field survey of rotting
beets, the fungi most frequently associated with root rot included Fusarium spp. (Fusariumoxysporum and Fusarium
acuminatum with 24% and 15% of isolates, respectively), Geotrichum spp. (16% of isolates), Rhizoctoniasolani (15%
of isolates), and Mucor spp. (14% of isolates). However, only R.solani isolate F321 (AG-2-2IIIB) consistently caused
rot in greenhouse pathogenicity tests. In the field survey, a mean of 6% of the root tissue had rotted for individual
roots when fungi were isolated individually, whereas mean root rot was 71% and 68% when bacteria were isolated
individually or in combination with other organisms, respectively. In field trials, roots inoculated with F321 averaged
3%-5% fungal rot, whereas the percentage of root tissue with bacterial rot was 6%-78%, which supports survey
observations. Manure did not lead to root rots in the field. Traditionally, fungal root rots have been the main focus of
breeding programs; however, because of the root area rotted by lactic acid bacteria, especially Leuconostoc, these
bacteria should not be ignored in breeding efforts
Macroscopic and microscopic variation in recovered magnesium phosphate materials: Implications for phosphorus removal processes and product re-use
Get PDFPhosphorus (P) recovery and re-use will become increasingly important for water quality protection and
sustainable nutrient cycling as environmental regulations become stricter and global P reserves decline.
The objective of this study was to examine and characterize several magnesium phosphates recovered
from actual wastewater under field conditions. Three types of particles were examined including crystalline
magnesium ammonium phosphate hexahydrate (struvite) recovered from dairy wastewater, crystalline
magnesium ammonium phosphate hydrate (dittmarite) recovered from a food processing facility,
and a heterogeneous product also recovered from dairy wastewater. The particles were analyzed using
‘‘wet” chemical techniques, powder X-ray diffraction (XRD), and scanning electron microscopy in conjunction
with energy dispersive X-ray spectroscopy (SEM–EDS). The struvite crystals had regular and
consistent shape, size, and structure, and SEM–EDS analysis clearly showed the struvite crystals as a surface
precipitate on calcium phosphate seed material. In contrast, the dittmarite crystals showed no evidence
of seed material, and were not regular in size or shape. The XRD analysis identified no crystalline
magnesium phosphates in the heterogeneous product and indicated the presence of sand particles. However,
magnesium phosphate precipitates on calcium phosphate seed material were observed in this product
under SEM–EDS examination. These substantial variations in the macroscopic and microscopic
characteristics of magnesium phosphates recovered under field conditions could affect their potential
for beneficial re-use and underscore the need to develop recovery processes that result in a uniform, consistent
product
The effect of extraction, storage, and analysis techniques on the measurement of airborne endotoxin from a large dairy
Get PDFThe objective of this study was to fill in
additional knowledge gaps with respect to the
extraction, storage, and analysis of airborne endotoxin,
with a specific focus on samples from a dairy
production facility. We utilized polycarbonate filters
to collect total airborne endotoxins, sonication as the
extraction technique, and 0.05% Tween 20 in pyrogen-
free water (PFW) as the extraction solution.
Endotoxin concentrations were determined via the
Limulus amebocyte lysate (LAL) assay. The endotoxin
concentrations in extracts after 15 and 30 min
of filter sonication were similar, while the concentration
in 60 min extracts was about twofold lower.
Rapidly vortexing samples for up to 15 min after
sonication did not increase the endotoxin concentration.
However, concentrations were 13 and 26%
lower in extracts that were centrifuged at 1,000 and
10,000g for up to 15 min, respectively. Field samples
and endotoxin standard were also sonicated in glass
or polypropylene tubes for up to 120 min. Regardless
of the extraction vessel, a decrease in endotoxin
concentration occurred when sonicated for[30 min.
Samples and endotoxin standard subjected to 12
freeze–thaw cycles at -20�C only showed a slight
but not significant decrease in endotoxin concentration.
Our results also demonstrate the importance of
simultaneously adding LAL reagent to 96-well plates
before initiating the LAL assay
Potential runoff and erosion comparison of four center pivot sprinklers
Get PDFThe operational characteristics of center pivot sprinklers are well documented but few
studies have been conducted to evaluate the effects that operating characteristics of a particular
sprinkler have on infiltration, runoff, and erosion of specific soil types. The objective of this study was
to evaluate potential runoff and erosion from common commercial center pivot sprinklers on three
widely distributed, south central Idaho soils. A modified commercial irrigation boom system was
used to emulate center pivot irrigation on experimental runoff plots. Sprinklers used in the study
were: 1) Nelson R3000 with brown plate, 2) Nelson R3000 with red plate, 3) Nelson S3000 with
purple plate, and 4) Senninger I-Wob with standard 9-groove plate. There were significant
differences in measured runoff percentages and measured erosion rates between center pivot
sprinkler types for the soils tested and experimental conditions. The magnitude of the differences
among sprinklers was equal to or greater than the differences between the soils tested. The I-Wob
and S3000 sprinklers exhibited the greatest measured runoff percentages and measured erosion
rates and the R3000 sprinklers exhibited the least runoff and erosion for the three soils tested. In
general, sprinkler types that visually appear to more evenly distribute sprinkler droplets over the
wetted area with respect to time exhibited the greatest measured runoff and measured erosion rates.
The relative ranking of the sprinklers in terms of measured runoff percentages and measured erosion
rates was consistent when four and six irrigation events were used to apply 75 mm of water. The
relative differences in runoff between the sprinklers tested were not directly proportional to sprinkler
droplet kinetic energy per unit water volume applied. This outcome is in conflict with conventional
theory on soil surface sealing from droplet impact. Possible explanations include incorrect
representation of sprinkler droplet kinetic energy, conventional soil surface sealing theory does not
apply to the soils used in this study, or some unknown factor is dominating the infiltration and runoff
process for the study conditions
Toxicity of various anionic polyacrylamide formulations when used as erosion control agents in agriculture
Get PDFAddition of anionic polyacrylamide (PAM) to agricultural
irrigation water can dramatically reduce erosion of soils.
However, the toxicity of PAM to aquatic life, while often
claimed to be low, has not been thoroughly evaluated. Five PAM
formulations, including two oil-based products, one waterbased
product, one granular product and one tablet product,
were evaluated for acute and/or chronic toxicity to fi ve species
commonly used for freshwater toxicity testing [Hyalella azteca
(Saussure), Chironomus dilutus (Shobanov et al.), Ceriodaphnia
dubia (Richard), Pimephales promelas (Rafinesque), and
Selenastrum capricornutum (Printz)]. When applied as an oilbased
product, acute toxicity was seen to four of the five species
at concentrations less than the 10 mg/L that is often used for
erosion control. Toxicity was diminished, but still remained,
after passage of the irrigation water across an agricultural field,
indicating a potential impact to nearby surface waters. Results
from the non-oil-based products indicated minimal toxicity
associated with PAM even at concentrations 10 times those used
in agriculture when applied in the granular form, as a tablet, or
in a water-based liquid. These data suggest that other agents in
the oil-based products, such as surfactants or emulsifiers, rather
than the PAM itself, contribute to the toxicity. Care is required
in selecting an appropriate PAM formulation when the potential
exists for entry of tailwater to nearby surface waters