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Diurnal shifts in nutritive value of alfalfa harvested as hay and evaluated by animal intake and digestion
Get PDFForages accumulate nonstructural carbohydrates
during the day, with animals showing
preference and improved daily responses from
afternoon compared with morning cut hays. This
study evaluated alfalfa (Medicago sativa L.) hay
harvested at 0700, 1000, 1300, 1600, and 1900
h to determine how nutritive value changes during
the day and to assess the impact of these
changes on animal preference using cattle (Bos
taurus L.), sheep (Ovis aries L.), and goat (Capra
hircus L.) responses. Total nonstructural carbohydrates
were altered by time of cut (cubic contrast,
P < 0.01) ranging from 85 g kg−1 at 0700 h
to 83 g kg−1 at 1000 h, then increasing to 97 g
kg−1 by 1600 h with little change at 1900 h (96 g
kg−1). Fiber fractions also varied diurnally, with a
quadratic decrease from 418 g kg−1 at 0700 h to
387 g kg−1 by 1900 h in neutral detergent fiber. A
combined analysis of three animal trials showed
a linear increase in dry matter intake (DMI) with
later hay harvest, a cubic response for dry matter
digestion (DMD), and a linear increase in
digestible DMI. Mean DMI increased from 27.5
g kg−1 body weight at 0700 h to a maximum
of 30.8 g kg−1 body weight at 1600 h, whereas
DMD decreased from 658 g kg−1 at 0700 to 647
g kg−1 at 1300 h and peaked at 664 g kg−1 at
1600 h. Digestible DMI increased from 18.1 g
kg−1 body weight at 0700 h to a maximum of
20.5 g kg−1 body weight at 1600 h. No additional
advantages in animal responses were noted by
cutting after 1600 h
Polyacrylamide (PAM) for irrigation runoff management
Get PDFNearly two million U.S. irrigated acres safely use PAM for erosion control, water quality
protection, and infiltration management, preventing 20 million tons of soil loss annually.
Nutrients, pesticides, chemical oxygen demand, weed seeds, and pathogens in runoff from
PAM-treated irrigation are greatly reduced. Typical annual PAM application amounts are <
10 kg ha-1 . At these rates, infiltration is improved on medium to fine-textured soils. PAM
applied at recommended rates has little or no effect on soil microflora and microfauna. Field
research has shown that applications of up to 5.4 ton ha -1 active ingredient (a.i.) of PAM have
only modest effects on soil microflora numbers and function and that PAM degrades at a rate
of at least 9.8% y-1 . Key points of PAM technology are presented
Environmental implications of inositol phosphates in animal manures
Get PDFAnimal production in the USA is valued at more
than $100 billion and has consolidated significantly
during the last 20 years, with a larger
number of animals being produced on an
increasingly smaller land base (Kellogg et al.,
2000). Manure generated from animal production
is currently estimated to exceed 335 million t
of dry matter per year in the USA, while global
manure production is estimated at —13 billion t
of dry matter per year (Mullins et al., 2005).
Manures contain significant amounts of phosphorus,
with values between 6.7 and 29.1 g P/kg on
a dry weight basis reported for several species
of animals (Barnett, 1994). This phosphorus
includes inorganic and organic forms, with the
latter constituting between 10°/a and 80% of the
total (Peperzak et al., 1959; Gerritse and Zugec,
1977). Inositol phosphates are one of the primary
organic phosphorus species found in manures,
with myo-Inositol hexakisphosphate typically
being the most abundant (Peperzak el al., 1959;
Barnett, 1994; Turner and Leytem, 2004)
Matrix-based fertilizers: A new fertilizer formulation concept to reduce nutrient leaching
Get PDFWe compared the efficacy of matrix based fertilizers (MBFs) formulated to reduce NO 3 -,
NH4+ , and total phosphorus (TP) leaching, with Osmocoate® 14-14-14, a conventional
commercial slow release fertilizer (SRF), and with an unamended control in greenhouse
column studies. The MBF formulations covered a range of inorganic N and P in compounds
that are relatively loosely bound (MBF1) to more moderately bound (MBF2) and more tightly
bound compounds (MBF3) mixed with Al(SO 4)3 H2O and/or Fe2(SO4 )3 and with high ionic
exchange compounds starch, chitosan and lignin. When N and P are released, the chemicals
containing these nutrients in the MBF temporarily bind N and P to a Al(SO4 )3 H2O and/or
Fe2(SO4 )3 starch- chitosan- lignin matrix. One milligram (8000 spores) of Glomus intradices
was added to all formulations to attempt to enhance nutrient uptake. In this first series of
experiments, soil columns were planted to white soft spring wheat (Triticum aestivum L.cv.
Frame).
Three soils were used, a sand, a loam and a loamy sand. In several studies, SRF leachate
contained higher amounts of NH4+ , NO3 " and TP than leachate from all other fertilizers.
Although plant biomass and yield with MBF was reduced in the first series of experiments,
follow-up studies have shown that formulation adjustments allow comparable plant responses
among SRF and MBFs. There were no consistent differences in the amount of NH4+ , NO3 -
and TP in the MBF leachates compared to the control leachate. Arbuscular mycorrhizal
infection in plant roots did not consistently differ among plants growing in soil receiving SRF,
MBFs and control treatments. The efficacy of MBF fertilizer strategy to reduce N and P
leaching to surface has been verified and with continued work to optimize formulations this
technology is expected to provide a new approach for groundwater protection, especially in
easily drained soils. The approach has been submitted for patenting
USDA-ARS sugar beet germplasm developed in Salinas, CA, evaluated for rhizomania resistance in Idaho
Get PDFThirty-one sugar beet germplasm breeding lines and releases produced by the USDA-ARS sugarbeet
program at Salinas, CA, and one line from the USDA-ARS sugarbeet program at East Lansing, MI, were
evaluated for resistance to rhizomania under south-central Idaho conditions at Twin Falls, ID. The field had been
identified as having Beet necrotic yellow vein virus (BNYVV), which overcomes resistance conditioned by the
Rzl gene. Single-row plots 10 ft long with 22-in. spacing were planted on 23 May 05. Plants were thinned to 4 to
6-in. spacing in mid-Jun. The materials were predominantly multigerm; they were hand thinned to single plants
during the first week of Jul. The trial layout was a randomized complete block with eight replicates, however, the
blocks were divided into 16 sub-blocks of six rows in which single-row plots of two entries and four control lines
were randomized. The control lines were Beta443OR (Rzl gene), GO17R (Rz2 gene), Angelina (Rzl+Rz2 genes)
and Beta6600 (no resistance to rhizomania). This allowed each entry plot to have its own control (Local Control).
This was necessary given the uneven distribution in the field of resistance breaking strains of BNYVV. Naturally
occurring Curly top virus infection was found throughout the field early in the season. Many plants of the
rhizomania susceptible control were killed apparently by curly top and therefore this should be considered when
evaluating the results. Plants were scored 19 Sep for curly top using a 0-9 scale with 0 showing no symptoms and
9 being dead. Plants were topped, roots lifted then scored on 12-13 Oct. Four teams evaluated the trial for
rhizomania with each team rating two replicates. Each root was scored based on the traditional 0 to 6 scale which
was converted to a 0 to 9 scale. The categories were 0, 1, 3, 5, 6, 7 and 9 with 0-3 being resistant, 5-7 susceptible
and 9 was dead. The average disease severity was determined to create a disease index (DI) for each entry and
control. A second index (DI2) was calculated for each entry-plot to evaluate the entry relative to the mean of the
Rz2 and Rzl+Rz2 Local Controls (DI of entry/mean DI of the Rz2 and Rzl+Rz2 Local Controls). The percent
healthy roots (categories 0-3 combined) and the percent of healthy roots relative to Rz2 and Rzl+Rz2 Local
Controls were calculated (PR and PR2, respectively). The DI and DI2 were transformed with the inverse square root
and analyzed using PROC MIXED - SAS with Dunnett's test (P = 0.05) option and PROC GLM – SAS with
Fisher's protected LSD test (P = 0.05) option, respectively. PR and PR2 were analyzed with PROC GLM –SAS
using Dunnett's test (P = 0.05) and Fisher's protected LSD (P = 0.05) test, respectively. The analysis of variance
of DI2 showed that block effects were significant, therefore Spearman's partial correlation (PROC CORR
Spearman partial - SAS) was used to analyze the relationship of D1, PR, DI2, PR2, and curly top. PROC CORR
Spearman -SAS was used to analyze the relationship between DI and DI2
Sprinkler and surface irrigation effects on return flow water quality and quantity
Get PDFA major conservation practice in the Upper Snake-Rock (USR) watershed is the conversion
from furrow irrigation to sprinkler irrigation. We compared the effect of irrigation system type on water
quality and quantity at the watershed scale. Six small watersheds (150-700 ha) were identified with 5 to
70% of the cropland sprinkler irrigated and the remaining fields surface or furrow irrigated. Other
agricultural land uses, cropping practices and soils were similar among watersheds. Water quality and
quantity entering and exiting each watershed were measured with automated samplers during the irrigation
season. Irrigation inflow to watersheds and outflow from watersheds did not decrease as sprinkler irrigated
area increased. This probably results from the flow rate allocation system used on the Twin Falls irrigation
tract. Annual sediment loss (r=-0.19, P=0.40) and concentration (r=-0.38, P=0.30) also did not correlate
with the relative amount of sprinkler irrigated area. Annual sediment loss (r-0.87, P=0.03) and
concentration (r-0.84, P=0.05) correlated with irrigation inflow—the more irrigation water delivered to a
watershed the greater the outflow sediment concentration and loss. These preliminary results indicate that
irrigation water delivery should be managed in addition to converting to sprinkler irrigation to improve
water quality in this irrigated watershed
Inhibiting water infiltration with cross-linked polyacrylamide: Seepage reduction for irrigated agriculture
Get PDFHigh water infiltration rates in unlined canals, reservoirs, and the inflow end of furrows relative
to outflow ends result in excessive seepage losses and reduced furrow irrigation application uniformity.
This study evaluated the use of cross-linked, anionic, polyacrylamide hydrogel (XPAM), a
water-absorbing, swellable polymer solid, for reducing infiltration and seepage losses though soil.
Experiments 1 and 2 measured the influence of soil treatments on seepage rate in soil columns
under constant-head conditions: Exp. 1 treated five soils with 0, 2.5, 5, and 10 g kg -1 XPAM; Exp.
2 applied combined XPAM (0-5 g kg-1) and NaC1 (0-5.1 g kg-1) treatments to a silt loam soil,
and separately tested the effect ofXPAM granule size and treated soil layer thickness on seepage rate.
In Exp. 3, a miniflume was used to determine how a 5-mm-thick, XPAM-treated (0-5 g kg- 1 ) soil
layer at the inflow end of the "minifurrow" influenced water distribution. The 21-h seepage rates of
all soils except the loamy sand decreased curvilinearly with increasing )(PAM rate, with maximum
reductions of 87 to 94% for 5 and 10 g kg -1 XPAM rates, relative to controls. The <300-pm-diam.
XPAM granules were significantly more effective than the coarser grained )(PAM for reducing seepage,
and reducing the thickness of the treated soil layer from 71 to 24 mm had no significant effect
on the seepage reduction obtained with XPAM. The 5 g kg- 1 XPAM treatment applied to inflow-end
miniflume soils significantly decreased the "furrow-stream" advance period and reversed the
infiltration patterns observed in miniflumes, relative to controls. These XPAM treatments could
potentially be used to increase the uniformity of furrow water applications and reduce seepage from
unlined irrigation ponds and canals
Relationship of beet curly top foliage ratings to sugar beet yield
Get PDFSugar beet (Beta vulgaris) varieties were evaluated for disease resistance to curly top to establish
if disease ratings made in inoculated nurseries correlated with disease ratings and yield in sugar
beet crops exposed to natural disease outbreaks. Cultivars were planted both in inoculated curly
top nurseries in Kimberly, ID, and in commercial cultivar trials in irrigated fields near Ontario,
OR and Nampa, ID. Plants were evaluated for curly top using a rating scale of 0 (no symptoms)
to 9 (dead). Moderate disease pressure in the Ontario (mean rating = 3.8) and Nampa (mean
rating = 4.1) fields resulted in significant differences for disease rating, root yield, sugar content,
and estimated recoverable sugar among cultivars. Disease ratings from both commercial fields
were positively correlated (r = 0.91 and 0.82, P < 0.0001) with ratings from the inoculated nurseries.
In commercial fields, root yield was negatively related to disease rating (r2 = 0.47 and
0.39, P ≤ 0.0004). For each unit increase in disease rating (increasing susceptibility), root yield
decreased 5.76 to 6.93 t/ha. Thus, curly top nurseries reliably predict curly top resistant cultivars
for commercial cultivatio
Polyacrylamide in agriculture and environmental land management
Get PDFAnionic polyacrylamide (PAM) has been sold since 1995 to reduce
irrigation-induced erosion and enhance infiltration. Its soil stabilizing and
flocculating properties improve runoff water quality by reducing sediments,
N, dissolved reactive phosphorus (DRP) and total P, chemical oxygen
demand (COD), pesticides, weed seeds, and microorganisms in runoff. PAM
used for erosion control is a large (12-15 Mg mol -1) water-soluble (non-cross-linked)
anionic molecule, containing <0.05% acrylamide monomer.
In a series of field studies, PAM eliminated 80-99% (94% avg.) of sediment
in runoff from furrow irrigation, with a 15-50% infiltration increase compared
to controls on medium to fine-textured soils. Similar but less dramatic results
occur with sprinkler irrigation. In sandy soils infiltration is often unchanged
by PAM or can be slightly reduced. Typical seasonal application totals in
furrow irrigation vary from 3 to 7 kg ha -1 . Research has shown little or no
consistent adverse effect on soil microbial populations. Some evidence exists
for PAM-related yield increases where infiltration was crop-limiting, especially
in field portions having irregular slopes, where erosion prevention
eliminated deep furrow cutting that deprives shallow roots of adequate
water delivery. Modified water management with PAM shows great promise
for water conservation. High effectiveness and low cost of PAM for erosion
control and infiltration management, coupled with easier implementation
than traditional conservation measures, has resulted in rapid adoption.
About 800,000 ha of US irrigated land use PAM for erosion and/or infiltration
management. In recent years, PAM has been deployed for uses beyond
agricultural erosion control, including construction site erosion control, use
in storm water runoff ponds to accelerate water clarification, soil stabilization
and dust prevention in helicopter-landing zones, and various other high-traffic
military situations. Among the newest topics being researched is the
use of PAM to reduce ditch, canal, and pond seepage, using specific application
protocols that take advantage of its increase of water viscosity at higher
concentrations
Changes in soil test phosphorus from broiler litter additions
Get PDFNutrient surpluses on the Delmarva Peninsula have led to a continual accumulation
of soil test phosphorus (STP), a potential source for transport of phosphorus (P)
to surface waters. This article examines the effects of initial soil test P concentrations
and broiler litter additions on STP accumulation. Broiler litter (BL) was applied at
rates of 0, 2.5, 5, 7.5, and 10 g kg -1 (dry weight) to three soils: an Evesboro sandy
loam (Mesic, coated Typic Quartzipsamments), a Pocomoke sandy loam (coarseloamy,
siliceous, thermic typic Umbraquults), and a Matapeake silt loam (fine-silty,
mixed, semiactive, mesic Typic Hapludults). Soils and BL were incubated for 16
weeks with subsamples analyzed after 4 and 16 weeks. There was a linear increase in
STP (Mehlich-3), water-soluble P (WS-P), iron-oxide strip-extractable P (FeO-P), and
Mehlich-3 phosphorus saturation ratio (M3-PSR) with broiler litter additions. Regression
analysis indicated few significant differences in STP response to added BL between soils
within the same soil group having different initial STP levels. Correlation analysis and
stepwise regression indicated that increases in WS-P and FeO-P from added BL were
more closely related to the degree of P saturation of the soil rather than traditional STP
measurements. Therefore, decisions regarding manure placement within a watershed
should be based on the potential P sorption capacity of the soil as well as potential P
transport pathways when the goal is the reduction of P transfer to waterbodies