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Compost amendments decrease Verticilliuam dahliae infection in potato
Get PDFIndigenous soil microorganisms contribute to disease suppression in cropping systems by reducing and
competing with pathogen populations, thereby limiting disease severity. Various communities of indigenous
microorganisms in any particular soil have adapted to the specific environmental conditions. If the
soil around the plant roots could be altered to favor the indigenous soil microorganisms relative to the plant
pathogen, the survival and proliferation of indigenous soil microorganisms, and thus effectiveness of biological
control, may be increased. Wood chip-polyacrylamide (PAM) cores were used to alter the soil environment
in a greenhouse study to favor indigenous soil microorganisms in vegetable and manure compost
to reduce Verticillium dahliae infection of potato (Solarium tuberosum L.) plants. Potato plants growing in soils
amended with vegetable compost-wood chip-PAM cores had significantly lower visible (V vis,) and isolation
(V iso)
dahliae infection rates than control soils and soils with dairy or vegetable compost alone. Soils
amended with wood chip-PAM-dairy compost cores had significantly lower IC and isolation V. than
control soils and soils with dairy compost. Soils with wood chip-PAM cores and soils with wood chip-PAM-vegetable
compost had greater microbial biomass/ Verticillium dahliae biomass (MB/ VB) ratios in soil
than control soils or in soils amended with compost alone. MB / VB ratios in wood chip-PAM cores and
wood chip- PAM-vegetable compost were greater than in wood chip-PAM-dairy compost cores. V correlated
in a quadratic relationship with the MB /VB ratio (r 2=0.76). As MB /VB ratio increased
Although field studies with several crops and economic evaluations are necessary, this greenhouse
study provides evidence that a wood chip-PAM or wood chip- PAM-vegetable compost soil amendment
may be a viable method to control some soil diseases in high value crops
The nature of phosphorus in calcareous soils
Get PDFCalcareous soils (containing free lime) are common in many arid and semi-arid regions
of North America and occur as inclusions in more humid regions. Phosphorus
(P) is very reactive with lime. Following fertilizer application, P undergoes a series of
reactions that gradually reduce its solubility. In most calcareous soils, there does
not appear to be a strong agronomic advantage of any particular P source when
managed properly. Organic matter can inhibit P fixation reactions to some extent.
Some fertilizer recommendations call for additional P to be added when the soil
contains high amounts of free lime
Field testing of a variable rate sprinkler and control system for site-specific water and nutrient application
Get PDFDevelopment and implementation of site-specific sprinkler irrigation management has been limited due to the lack
of variable rate sprinklers. Thirty-two prototype variable rate sprinklers were constructed and field tested on a three-span
linear-move irrigation system. An algorithm was developed for a distributed control network to allow each sprinkler to be
individually controlled in groups of six or seven along the linear-move lateral. Water application uniformity was monitored
over a 36% to 100% range in application rate. Measured application uniformity equaled or exceeded 90%. Variable rate
nitrogen application was monitored over a 1.1-ha area. Measured nitrogen application rate was within 4% of the target
application rate. Results indicate that the prototype variable rate sprinkler and control system allows water and chemical
application to vary over a 36% to 100% range in application rate with minimal effect on water application uniformity
Freezing and thawing processes
Get PDFSeasonally frozen soil strongly influences runoff and
erosion on large areas of land around the world. In
many areas, rain or snowmelt on seasonally frozen
soil is the single leading cause of severe runoff and
erosion events. As soils freeze, ice blocks the soil
pores, greatly diminishing the permeability of the
soil. This is aggravated by the tendency of water to
migrate to the freezing front, causing elevated ice
content and frost heav
Fungi in the root cortex of direct-seeded wheat fields with chiseling or no tillage
No full textPlease contact the NWISRL if you have a copy of this publication
Managing curly top
Get PDFCurly top of sugarbeets caused by Beet curly top virus (BCTV) was widespread from
southeastern Oregon to southcentral Idaho in 2004. Curly top first became a serious
threat to sugarbeet production in southern Idaho in 1919. By the time the first resistant
variety was released in 1935, BCTV had almost eliminated the sugarbeet industry (2).
Today this disease is largely managed through the use of resistant varieties. Early
planting and the use of systemic insecticides (phorate, aldicarb, and imidicloprid) will
also help limit curly top (1,2,4)
Phosphorus loss with surface irrigation
Get PDFDefinition:
Surface irrigation uses
gravity to deliver water
across the field, contrary
to sprinkler or drip irrigation
that uses pipe or tubing
as the conveyance system.
Water flows across the field
in small streams for furrow
irrigation or in a sheet for
border and basin irrigation.
Problem:
In some surface irrigation
systems, runoff is desirable
to improve the uniformity
of water infiltration between
the upper and lower
ends of the field. Containing
all runoff from sloping fields
(>1 percent) is also impractical.
During the irrigation
event, water flowing over
soil detaches, transports and
deposits sediment and nutrients
that are often attached
to sediment. Phosphorus (P)
can also desorb from the
soil and transported sediment,
increasing soluble P
in surface irrigation runoff.
Therefore, there are two
main mechanisms that influence
P transport in these
systems: erosion and desorption
of P into runoff water
Carbon sequestration in irrigated pastures
Get PDFCarbon sequestration potential for irrigated grazing lands is significant. We measured organic and
inorganic C stored in southern Idaho soils having long-term land use histories that supported native sagebrush
vegetation (NSB), irrigated pasture systems (IP), irrigated conservation tillage sites (ICT), and irrigated
moldboard plowing systems (IMP). This study estimates the amount of possible organic, inorganic and total C
sequestration if irrigated pasture land was expanded by 10%
Nutritional requirements of potatoes
Get PDFPlant nutrition is the practice of providing to the
plant the right nutrient, in the right amount, in the right
place, at the right time. This paper gives an overview of
the roles that each of the 16 essential nutrients have in
plant nutrition, their relative mobility as related to deficiency
symptom expression, and what is generally
known about nutrient responses to field applications on
potatoes (Solanum tuberosum L.) in the USA and
Canada. Maintaining high crop yields with minimum
nutrient losses to the environment is and will continue
to be a significant challenge to the potato producer.
Additional nutritional research efforts in genetically
modified plants, precision agriculture, food quality and
safety, fertilizer impurities, and other management concerns
should significantly help the producer in this
effort
Evaluation of experimental sugarbeet hybrids for resistance to beet curly top in Canyon County, ID, 2004
Get PDFExperimental sugarbeet hybrids were evaluated for resistance to Beet curly top virus in a commercial sprinkler irrigated
sugarbeet field near Nampa, ID where beet curly top had been a problem in previous years. The field trial relied on
natural infection and was planted on 19 Mar. The plots were planted to a density of 190,000 seeds/A, and thinned to
35,640 plants/A. Plots were four rows wide (22 in -row spacing) and 36 ft long. The experimental design was a randomized
complete block design with seven replications. The crop was managed by the grower according to standard cultural
practices. The weather during the growing season was cooler than normal and disease pressure was uniform and
moderately severe. Disease data were recorded on 14 Sept by three raters using a disease index of 0 to 9 (no symptoms to
dead). The three ratings per plot were averaged prior to analysis. The center two rows were harvested on 20 Oct using a
small plot harvester. The sugar content of the beets was determined by the Amalgamated Sugar Co. laboratory, and
recoverable sugar (lb/A) was estimated. Data were analyzed using the general linear models procedure (Proc GLM-SAS),
and Fisher's Protected LSD was used for mean comparisons.
Yields were above average and disease pressure was moderately severe. The experimental hybrids response to Beet
curly top virus ranged from acceptable (slight leaf curl to most leaves with moderate curling) to moderately affected (severe
leaf curling). Analysis of variance indicated there were significant differences among hybrids in disease index, root yield,
sugar content, and estimated recoverable sugar. Disease index for hybrids in this test were positively correlated (r s = 0.632,
P < 0.0001) with ratings from the 04 Curly Top Nursery in Kimberly, ID. Based on Spearman's Coefficient of Rank
Correlation (rs = -0.15, P = 0.4651), there was no correlation between estimated recoverable sugar and disease index. This
lack of correlation between estimated recoverable sugar and disease index was likely not related to variation associated with
the disease rating but rather due to other factors such as field and genetic variation that influenced yield.
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