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Management of irrigated agriculture to increase organic carbon storage in soils
Get PDFIncreasing the amount of C in soils may be one method to reduce the concentration of
C02 in the atmosphere. We measured organic C stored in southern Idaho soils having long
term cropping histories that supported native sagebrush vegetation (N SB), irrigated moldboard
plowed crops (IMP), irrigated conservation -chisel- tilled crops (ICT) and irrigated pasture
systems (1?). The C02 emitted as a result of fertilizer production, farm operations and CO;
lost via dissolved carbonate in irrigation water, over a 30 year period, was included. Net
organic C in ecosystems decreased in the order IP>ICT>NSB>IMP. In this study, if NSB were
converted to IMP, 0.15 g C m“2 would be emitted to the atmosphere, but if converted to IP
, 3.56 g C m'2 could be sequestered. If IMP land were converted to ICT, 0.95 g C m"2 could be
i sequestered in soil and if converted to I? 3.71 g C 111'2 could be sequestered. There are 2.6)(108
ha of land worldwide presently irrigated. If irrigated agriculture were expanded 10% and the
same amount of rainfed land were converted back to native grassland, an increase of 3.4x109
Mg C (5.9% of the total C emitted in the next 30 yr) could potentially be sequestered. The
total projected release of CO2 is 5.7x10‘° Mg C worldwide during the next 30 years.
Converting rainfed agriculture back to native vegetation while modestly increasing areas in
f irrigated agriculture could have a significant impact on C0; atmospheric concentrations while
maintaining or increasing food production
Center pivot simulator for evaluating system design and management effects on infiltration and erosion
Get PDFA 4-wheeled commercial irrigation boom was modified for use in investigating center pivot design and
management effects on infiltration, runoff and erosion of specific soil types. The center pivot simulator
used a hydraulic winch attached to the front of a tractor for mobilization and controlled travel speed. A 3
inch diameter 300 ft drag hose is used to supply water to the center pivot simulator. The center pivot
simulator was used to conduct two studies to investigate infiltration, runoff and erosion differences of
common commercially available center pivot sprinkler types on a Portneuf silt loam soil. Sprinklers used
in the first 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. Measured runoff was
highly variable despite the controlled experimental conditions. Runoff from all sprinkler types increased
with number of irrigations indicating that soil surface sealing continued to increase without reaching a
maximum after five irrigations. Measured runoff tended to be the highest for the S3000 and I-Wob
sprinklers. Sediment loss tended to be highest for these sprinklers as well. The second study investigated
differences in runoff and erosion related to kinetic energy of sprinkler droplets from commercial center
pivot sprinklers. The sprinklers used in the study were: 1) Senninger I-Wob with standard 9-groove
plate, 2) Nelson R3000 with brown plate, 3)Nelson D3000 spray with flat plate and 4) sprinkler 3 with the
runoff plot covered with 20-mesh nylon window screen suspended about 1 inch above the soil surface to
eliminate sprinkler droplet impact on the bare soil surface. Covering the plot with screen to eliminate
sprinkler droplet impact resulted in significantly (p≤0.05) less runoff and sediment loss for all four
irrigation events. The D3000 and I-Wob sprinklers tended to have the greatest runoff and sediment
losses. Sprinkler type and configuration had a significant (p≤0.05) effect on runoff and erosion of a
Portneuf silt loam soil
Comparative mapping of fiber, protein, and mineral content QTLs in two interspecific Leymus wildrye full-sib families
Get PDFCrude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), and mineral content are important components of forage quality in grasses. Elevated [K]/([Ca] + [Mg]) ratios (KRAT) substantially increase the risk of grass tetany (hypomagnesemia) in grazing animals, which is a serious problem associated with some cool-season grasses. The objectives of this study were to map and compare QTLs controlling concentrations of CP, NDF, ADF, Al, B, Ca, Cl, Cu, Fe, K, Mg, Mn, Na, P, S, Si, Zn, and KRAT in two full-sib Leymus triticoides × (L. triticoides × L. cinereus) TTC1 and TTC2 families. Significant genetic variation and QTLs were detected for all traits, with evidence of conserved QTLs for ADF (LG1a, LG5Xm, LG7a), NDF (LG7a), Ca (LG1b), CP, (LG5Xm), KRAT (LG3b, LG6b, LG7a, LG7b), Mn (LG2b, LG3b, LG4Xm), and S (LG3a) content in both TTC1 and TTC2 families. Moreover, the direction of QTL effects was the same for 13 of the 14 homologous QTLs in both families. The TTC1 and TTC2 KRAT QTLs on LG7a and LG7b were located near markers defining homoeologous relationships between the sub-genomes of allotetraploid Leymus, suggesting possible QTL homoeology. Another 88 QTLs were unique to one family or the other, but many of these clustered in genome regions common between the two families. These results will support development of new Leymus wildrye forages and help characterize genes controlling mineral uptake and fiber synthesis
Matrix based fertilizers reduce nitrogen and phosphorus leaching in greenhouse column studies
Get PDFWe tested the efficacy of matrix based
fertilizer formulations (MBF) that reduce NH4, total
phosphorus (TP), total reactive phosphorus (TRP) and
dissolved reactive phosphorus (DRP) in leachate. The
MBF formulations cover 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
(SO4)3 H2O and/or Fe2(SO4)3 and with the high ionic
exchange compounds starch, chitosan and lignin.
Glomus interadicies, a species of arbuscular mycorrhizal
fungal spores that will form mycorrhizae in
high nutrient environments, was added to the MBF
formulations to increase plant nutrient uptake. When
N and P are released from the inorganic chemicals
containing N and P the matrix based fertilizers likely
bind these nutrients to the Al(504)3 H2O and/or
Fe2(504)3 starch–chitosan–lignin matrix. We tested
the efficacy of the MBFs to reduce N and P leaching
compared to Osmocote® 14-14-14, a slow release
fertilizer (SRF) in sand filled columns in a greenhouse
study. SRF with and without Al and Fe leached 78-
84% more NH4, 58-78% more TP, 20-30% more
TRP and 61-77% more than MBF formulations 1, 2,
and 3 in a total of 2.0 liters of leachate after 71 days.
The concentration and amount of NO3 leached among
SRF and MBF formulations 1 and 2 did not differ.
The SRF treatment leached 34% less NO3 , than
MBF3. Total plant weight did not differ among
fertilizer treatments. Arbuscular mycorrhizal infection
did not differ among plants receiving SRF and MBF
formulations 1, 2 and 3. Although further greenhouse
and field testing are called for, results of this initial
investigation warrant further investigation of MBFs
Temporal and vertical distribution of soluble carbohydrate, fiber, protein, and digestibility levels in orchardgrass swards
Get PDFHerbage nonstructural carbohydrates (NC) contribute to livestock
performance and silage fermentation. Knowledge of the distribution
patterns of NC and other nutritional constituents in orchardgrass
(Dactylic glomerata L.) swards could support harvest management
decisions. Our objective was to determine diurnal and vertical patterns
of total NC (TNC), crude protein (CP), and neutral detergent fiber
(NDF) concentrations, and in vitro true dry matter digestibility
(IVTDMD) and NDF digestibility (NDFD) in orchardgrass swards
in October, June, and August. Herbage was sampled at 6-h intervals
between 0100 and 1900 h from horizons positioned 40 to 27, 27 to
18, 18 to 12, and 12 to 8 cm above soil surface. Herbage composition
varied among horizons in all months, and diurnally only in June
and August. In June and August, only TNC with maxima of 109 to
123 g kg-1 at 1900 h exhibited consistent diurnal patterns. Swards
harvested to residual heights of 18, 12, or 8 cm exhibited little spatial
variation in TNC during June and August, but CP, NDF, and
IVTDMD varied with harvest depth on all dates. As swards were
harvested to successively greater depths, TNC increased in October, but
not in June and August. In contrast, CP and IVTDMD decreased, and
NDF increased, for harvests to successively greater depths in all months.
For harvests in June and August, manipulation of depth would capture
more variation in CP, NDF, and IVTDMD, but manipulation of time of
day of harvest would capture more variation in TNC to meet animal
performance and silage fermentation requirements
Compost and manure effects on fertilized corn silage yield and nitrogen uptake under irrigation
Get PDFDairy manure increases the yields of dry bean (Phaseolus vulgaris L.) and
spring wheat (Triticum aestivum L.) from eroded, furrow-irrigated soils and may
increase corn (Zea mays L.) silage yield from steeper eroded areas under sprinkler irrigation.
In a 2-year field study in southern Idaho on Portneuf silt loam (coarse silty,
mixed, superactive, mesic Durinodic Xeric Haplocalcid), the effects of a one-time,
fall application of 29 or 72 Mg ha-1 of dry manure or 22 or 47 Mg ha21 of dry
compost on subsequent silage yield and nitrogen (N) uptake from previously eroded,
sprinkler-irrigated hill slopes were evaluated. In October 1999, stockpiled or
composted dairy manure was disked to a depth of 0.15 m into plots with slopes from
0.8 to 4.4%. After planting field corn in 2000 and 2001, a low-pressure, six-span
traveling lateral sprinkler system was utilized to apply water at 28 mm h21 in
amounts sufficient to satisfy evapotranspiration to 6.4- � 36.6-m field plots. Yields
in 2000 were 27.5 Mg ha21
, similar among all rates of all amendments and a fertilized
control. In 2001, compost applied at oven-dry rates up to 47 Mg ha-1 increased yield
compared to controls. Silage yield in 2001 increased initially then decreased with
increasing manure applications. Where compost or manure was applied, regardless
of rate, 2-year average N uptake was 15% greater than controls. Regardless of
treatment or year, yields decreased linearly as soil slope increased
Verticillium wilt in transgenic sugar beet cultivars in Cassia County, ID, 2006
Get PDFTransgenic (resistant to glyphosate) sugar beet cultivars were evaluated in a commercial sprinkler-irrigated sugar
beet field near Heyburn, ID where winter wheat was grown in 2005. The field trial relied on natural infection of Verticillium
dahliae. The plots were planted on 28 Apr to a density of 142,560 seeds/A, and thinned to 47,520 plants/A on 15-20 Jun.
Plots were four rows wide (22-in. row spacing) and 34.5 ft long. The experimental design was a randomized complete block
design with eight replications per cultivar. The field was cultivated on 8 and 20 Jun. The crop was managed by the grower
according to standard cultural practices except for herbicide applications. Transgenic cultivars were sprayed with broadcast
applications of glyphosate at 32 fl oz/A on 30 May and 22 fl oz/A on 27 Jun. The study area was also hand weeded to keep
all plots free of weeds. The percentage of plants with leaves that had dead vein delimited sectors was recorded for the center
two rows on 6 Sep. The center two rows were harvested on 25-26 Sep with the aid of a mechanical topper and small plot
harvester. The sugar content of the beets was determined by the Amalgamated Sugar Co. laboratory, and recoverable sugar
was estimated. Data were analyzed using the general linear models procedure (Proc GLM-SAS), and Fisher's protected least
significant difference was used for mean comparisons.
Yields from this field were below normal for this growing region. Verticillium dahliae symptoms and yield
parameters varied significantly between cultivars. Root shape and root hair proliferation indicated that Beet necrotic yellow
vein virus (BNYVV) also was present in the field although the foliar symptoms of this disease were not particularly evident.
An interaction between BNYVV and V. dahliae may have been present in this field. Based on Spearman's rank correlation
coefficient, the mean values for leaf symptoms were inversely related with those for root yield (r = -0.3667, P = 0.0504) but
not sugar content or estimated recoverable sugar (P = 0.1277 and 0.2182, respectively). Good resistance to V. dahliae exists
in some transgenic cultivars based on the reduction in foliar symptoms. Numerous transgenic cultivars with resistance to
both V. dahliae and BNYVV had better yield parameters than the commercial check cultivars indicating growers should be
able to switch to some of the resistant transgenic cultivars without experiencing yield loss
Dietary low-phytate mutant-M 955 barley grain alters phytate degradation and mineral digestion in sheep fed high-grain diets
Get PDFGreater production demands for ruminants require increased dietary inclusion of high-energy feeds. Grains and oil seeds are most commonly used to enhance diet energy density. However, use of such feeds proportionally increases the amount of dietary phytate phosphorus (P), which the ruminant may not be able to fully utilise. Our objectives for this study were to determine the extent of phytate degradation and mineral digestion in wethers fed high-grain diets consisting of either a non-mutant or low-phytate mutant barley grain. In two separate experiments, mature Columbia wethers (n = 7) fitted with rumen and duodenal cannulas and Columbia × Polypay wether lambs (n = 8) were individually fed one of two finishing diets formulated with either non-mutant Harrington (HARR) variety or low-phytate mutant-M 955 (M955) barley grains. Total-P intake was similar (P=0.46–0.70) between the M955 and HARR treatments for mature (5756 and 5550 mg/day, respectively) and lamb (5207 and 4894 mg/day, respectively) wethers. Dietary water-soluble P was 3.6 times greater in M955 versus HARR diets and phytate P was 11 times greater in HARR versus M955 treatment diets. Apparent total-P digestion was similar between M955 and HARR treatments (P=0.52–0.69). More monoester P was identified in the duodenal chyme of mature wethers fed HARR treatment diet, presumably due to incomplete hydrolysis of phytate P in the rumen. Feeding M955, compared to HARR, treatment diet resulted in greater (P<0.05) apparent partial-tract digestion of calcium (Ca) and total-tract digestion of iron (Fe), magnesium (Mg), and zinc in mature wethers and apparent total-tract digestion of Mg and Fe and retention of Ca, Fe, and Mg in wether lambs. These results indicate that phytate in diets formulated with Harrington variety barley grain may not be fully digested in the rumen. Subsequent passage of partially digested phytate from the rumen may interfere with mineral digestion in wethers fed high-grain diets
Phosphorus characterization in feces from broiler chicks fed low-phytate barley diets
Get PDFThe inclusion of low phytate grains in poultry diets can reduce the phosphorus (P) content of poultry
feces, but their influence on fecal P composition is not well established. To assess this, 100 male broiler chicks
(21 days old) were fed dietary treatments based on either a wild-type barley or one of three low phytate mutant
barleys with 59, 62 and 99% reductions in phytate P, compared with the normal barley diet. The birds were housed
in raised-floor battery cages with mesh grate floors above fecal collection trays with five birds per pen and five
pens per treatment. The birds were fed for 9 days and feces were collected twice a day during the last 2 days of the
experiment. Total P concentrations were 14-24% lower in feces from birds fed low phytate barley diets compared
with those fed the normal barley diet. Phosphorus digestibility increased (P < 0.05) as phytate in the barley diet
decreased. Phosphate was the major P fraction in the feces (69-75% extracted P) regardless of the type of barley
fed. Phytate constituted only 3-12% of the P in the feces, indicating its hydrolysis in the bird. Overall, these
results suggest that feeding low-phytate barley diets can reduce P concentrations in poultry feces without causing
significant changes in P composition
One-time tillage of no-till: Effects on nutrients, mycorrhizae, and phosphorus uptake
Get PDFStratification of nutrient availability, especially of P, that develops
with continuous no-till (NT) can affect runoff nutrient concentration
and possibly nutrient uptake. The effects of composted manure application
and one-time tillage of NT on the distribution of soil chemical
properties, root colonization by arbuscular mycorrhizae (AM), and
plant P uptake were determined. Research was conducted on Typic
Argiudoll and Moffic Hapludaff soils under rainfed corn (Zea mays L.)
or sorghum [Sorghum bicolor (L.) Moench.] rotated with soybean
[Glycine max (L.) Men.] in eastern Nebraska. Tillage treatments included
NT, disk, chisel, moldboard plow (MP), and mini-moldboard
plow (MMP). Subplots had either 0 or 87.4 kg P ha -I- applied in compost
before tillage. Bray-P1 was five to 21 times as high for the 0- to
5-cm as compared with the 10- to 20-cm soil depth. Greater redistribution
of nutrients and incorporation of compost P resulted from
MP tillage than from other tillage treatments. One-time chisel or disk
tillage did not effectively redistribute nutrients while MMP tillage had
an intermediate effect. Compost application reduced AM colonization
of roots at R6 for all crops. Tillage reduced AM colonization with
reductions at R6 due to MP tillage of 58 to 87%. The tillage effect
on colonization persisted through the second year with no indication
of AM recovery. Root P concentration was increased by MP and was
negatively correlated to colonization. Decreased colonization did not
result in decreased plant P uptake. Infrequent MP tillage can reduce
surface soil P and the potential for P loss in runoff, but may reduce
AM colonization of the roots, possibly reducing P uptake with some
low P soils. The results do not indicate any advantage to one-time tillage
of NT if runoff P loss is not a concern