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Beet curly top resistance in USDA-ARS plant introduction lines, 2017
Get PDFCurly top caused by Beet curly top virus (BCTV) is a widespread disease problem vectored by the beet leafhopper in semiarid sugar beet production areas. Host resistance is the primary defense against this problem, but resistance in commercial cultivars is only low to intermediate. In order to identify novel sources of curly top resistance, 30 sugar beet USDA-ARS Plant Introduction (PI) lines were screened in a disease nursery in 2017. The lines were arranged in a randomized complete block design with four replications. A curly top epiphytotic was created by releasing six viruliferous beet leafhoppers per plant at the four- to six-leaf growth stage on 14 June. Foliar symptoms were evaluated on 6 July using a scale of 0-9 (0 = healthy and 9 = dead) in a continuous manner. Curly top symptom development was uniform and no other disease problems were evident in the plot area. The disease pressure in the test was moderately severe with good symptom development in the susceptible checks. Based on the visual rating, three entries (2, 7, and 15) performed the same as the resistant check. These germplasm lines will be will be investigated further for incorporation into germplasm lines so they can be utilized to improve BCTV resistance in commercial sugar beet cultivars
Changes in groundwater quality and agriculture in forty years on the Twin Falls irrigation tract in southern Idaho
Get PDFBetter understanding agriculture’s effect on shallow groundwater quality is needed on the southern Idaho, Twin Falls irrigation tract. In 1999 and 2002-2007 we resampled 10 of the 15 tunnel drains monitored in a late-1960s study to determine the influence of time on NO3-N, dissolved reactive P (DRP), and Cl concentrations, and flow rates of shallow groundwater outflows.Since the late-1960s, an 8-fold increase in the dairy herd has driven shifts toward increased feed cropping, which, along with improved hybrids and production, increased inorganic and manure fertilizer use. The late-1960s to early-2000s period saw a consistent 1.4-fold increase in mean tunnel-drain outflow NO3-N concentrations (from 3.06 to 5.06 mg/L), a 10% decrease in mean Cl (from 49.2 to 44.2 mg/L), and an overall 14% decrease in DRP (14 to 12 µg/L). However, 3 of the 10 tunnels exhibited increased DRP concentrations during the period, and the rate of DRP increase was positively related to increasing encroachment of confined animal feeding operations or residential development. Decreases in tunnel flow between sampling periods were linearly related to corresponding increases in the fraction of sprinkler irrigation employed on lands drained by the tunnels (P = 0.01). Further conversion to sprinkler irrigation is unlikely to reduce tunnel drain NO3-N concentrations since the latter were unrelated to changes in sprinkler coverage. The amount and timing of applied N, and availability for crop uptake or leaching should be more carefully managed in these soils to prevent continued increases in groundwater NO3-N concentrations
Beet curly top resistance in USDA-ARS Ft. Collins germplasm, 2017
Get PDFCurly top caused by Beet curly top virus (BCTV) is a widespread disease problem vectored by the beet leafhopper in semiarid sugar beet production areas. Host resistance is the primary defense against this problem, but resistance in commercial cultivars is only low to intermediate. In order to identify novel sources of curly top resistance, 49 sugar beet lines produced by the USDA-ARS Ft. Collins sugar beet program were screened in a disease nursery in 2017. The lines were arranged in a randomized complete block design with four replications. A curly top epiphytotic was created by releasing six viruliferous beet leafhoppers per plant at the four- to six-leaf growth stage on 14 June. Foliar symptoms were evaluated on 6 July using a scale of 0-9 (0 = healthy and 9 = dead) in a continuous manner. Curly top symptom development was uniform and no other disease problems were evident in the plot area. The disease pressure in the test was moderately severe with good symptom development in the susceptible checks. Based on the visual rating, five entries (10, 16, 21, 34, and 46) performed the same as the resistant checks. These germplasm lines will be reevaluated for potential release to the general public so they can be utilized to improve BCTV resistance in commercial sugar beet cultivars
Nitrogen mineralization as affected by temperature in calcareous soils receiving applications of dairy manure
Get PDFCurrent data is lacking for prediction capability of N mineralization for the silty soils found in Southern Idaho receiving the repeated application of manures. The objectives of this experiment were to determine the effect of temperature on N mineralization from control and manured soils, develop N mineralization rate correction factors for temperature (Q10 and temperature factors), and create a simple model for predicting N mineralization as a function of cumulative heat units or growing degree days (GDD). Manured and control soils underwent a 49-d laboratory incubation at five different temperatures (-14, 4, 10, 23, and 30oC); soil inorganic N concentration was determined at 0, 1, 3, 5, 7, 13, 20, 28, 35, 42, and 49 d. Net N mineralization was fit to a zero-order model, where the rate coefficient (k) values for the manured soil ranged from 0.017 to 1.28 mg kg-1 soil d-1 over the five temperature treatments while k values in the control measured 0.028 to 0.53 mg kg-1 soil d-1. Calculated Q10 from -14 to 30oC were 2.7 and 2.0 for the manured and control soils, respectively. At low temperatures (-14 to 4oC), the Q10 for the manured soil was 5.1 compared to 1.5 for the control soil. This finding suggests that manure additions may lower the temperature threshold for N mineralization to occur under near frozen soil conditions. Manure treatment effects on temperature factor were not observed, suggesting that manure application history may not need to be considered when developing TF coefficients for N mineralization models
Beet curly top resistance in USDA-ARS Kimberly germplasm lines evaluated in Idaho, 2017
Get PDFCurly top caused by Beet curly top virus is a widespread disease problem vectored by the beet leafhopper in semiarid sugar beet production areas. Host resistance is the primary defense against this problem, but resistance in commercial cultivars is only low to intermediate. In order to identify novel sources of curly top resistance, 13 sugar beet lines were screened in a disease nursery in 2017. The lines were arranged in a randomized complete block design with six replications. A curly top epiphytotic was created by releasing six viruliferous beet leafhoppers per plant at the four- to six-leaf growth stage on 14 Jun. Foliar symptoms were evaluated on 6 Jul using a scale of 0-9 (0 = healthy and 9 = dead) in a continuous manner. Curly top symptom development was uniform and no other disease problems were evident in the plot area. The checks performed as expected for both the visual rating and ELISA. Based on both visual ratings and ELISA, KDH4-9 (PI683513) and KDH13 (PI663862) performed the same as the resistant check. All the KDH13 progenies (crossed to susceptible parental lines) had moderate visual ratings, while two of the progenies (KDH13/EMS9 and KDH13/19-19) had ELISA values that were not different from the resistant check. KDHEMS09 is new line that had very low virus accumulation. These results and germplasm information will be accessible through the USDA-ARS, NPGS GRIN database (http://www.ars-grin.gov/npgs/index.html). These germplasm lines will be released to the general public, so they can be utilized to improve curly top resistance in commercial sugar beet cultivars
Effects of manure history and nitrogen fertilizer rate on sugar beet production in the northwest U.S.
Get PDFPast manure applications effects on sugarbeet production needs to be assessed in the areas where manure applications to crop land are common. A study was conducted in Kimberly, Idaho in 2014 and 2016 to assess the effects of manure application history and N rates on sugarbeet production on a Portneuf silt loam (coarse-silty mixed mesic Durixerollic Calciorthid) soil. From 2004 to 2009, manure was applied to plots every two years (M1, total application = 60 tons per acre), every year (M2 total application = 106 tons per acre), or no manure (F, commercial fertilizer only). In spring 2014, the manure main plots were split in half with one half receiving a commercial fertilizer N rate treatment superimposed on the main plots in 2014 and the other half receiving the superimposed N rate treatments in 2016. In 2014 and 2016, the commercial fertilizer N rates were 0, 30, 56, 77, 100, 141, 180, and 202 pounds per acre. The study design was a randomized block split-plot with manure history as the main plot and N rate as the subplot. During both years of the study, N rate did not affect sugarbeet yields, but M1 and M2 treatments had higher sugarbeet root yields compared to the F treatment. Averaged across all N rates, root yields from both manured treatments were 12% and 36% greater than the F treatment in 2014 and 2016, respectively, although sugar yield was only significantly greater in 2016. Manure applications will impact sugarbeet production for several years after manure applications have ceased
Commercial sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2016
Get PDFRhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 22 commercial cultivars were screened by growing them in a sugar beet field infested with BNYVV in Kimberly, ID during the 2016 growing season in a randomized complete block design with 6 replications. At harvest on 4-5 October 2016, roots were dug and evaluated for symptoms of rhizomania and also placed in an indoor commercial sugar beet storage building. After 130 days in storage, samples were evaluated for surface rot, weight loss, and sucrose loss. Surface root rot ranged from 7 to 51%, weight loss ranged from 7.5 to 12.3%, sucrose losses ranged from 23 to 62%, and estimated recoverable sucrose ranged from 2,901 to 10,114 lb/A. Given these response ranges, selecting cultivars for rhizomania resistance and combining this resistance with storability will lead to considerable economic benefit for the sugar beet industry
Ammonia emissions from dairy lagoons in the western U.S.
Get PDFAmmonia (NH3) emissions from dairy liquid storage systems can be a source of reactive nitrogen (N) released to the environment with a potential to adversely affect sensitive ecosystems and human health. However, there has been little on-farm research conducted to estimate these emissions and determine the factors that may affect these emissions. Six lagoons in south-central Idaho were monitored for one year, with NH3 emissions estimated by inverse dispersion modeling. Lagoon characteristics thought to contribute to NH3 emissions were also monitored over this time period. Average daily emissions from the lagoons ranged from 5.7 to 45 kg NH3 /ha or 5.7 to 96 kg NH3. There was a general trend for greater emissions during the summer, when temperatures were greater, in addition high wind events and agitation of the lagoons created temporary increases in NH3 emissions irrespective of temperature. Lagoon physicochemical characteristics such as total Kjeldahl nitrogen (TKN) and total ammoniacal nitrogen (TAN) were highly correlated with emission. Ammonia emission prediction models were developed using TKN, TAN, wind speed, air temperature and pH as independent variables. An on farm N balance suggests that lagoon NH3-N losses represented 9% of total N lost from the facility, 65% of the total lagoon N and 5% of dairy herd N intake. A process based model estimated similar values for N excretion and NH3-N loss from the lagoon. On-farm work is necessary to better refine both process based models and emission factor estimates in order to more accurately account for NH3 emissions from lagoons on dairies in the western US
Ft. Collins sugar beet germplasm evaluated for rhizomania and storage rot resistance in Idaho, 2017
Get PDFRhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet germplasm lines with resistance to BNYVV and storage rots, 42 lines from the USDA-ARS Ft. Collins sugar beet program and five check cultivars were screened. The lines were grown in a sugar beet field infested with BNYVV during the 2017 growing season in a randomized complete block design with 6 replications. At harvest on 11 October 2017, roots were dug and evaluated for rhizomania symptoms and also placed in an indoor commercial sugar beet storage building. After 132 days in storage, samples were evaluated for the percentage of root surface area covered by fungal growth or rot. Rhizomania symptom development in the field was uniform and other disease problems were not evident in the plot area. The BNYVV susceptible check plots had 97 to 100% foliar symptoms and high root disease severity ratings. The three resistant checks had 0 to 6% foliar symptoms and low root ratings. Based on root ratings, all entries except entry 20151043PF had some level of resistance since they were all better than the susceptible checks. However, 20141018 was the only entry that performed well for all variables. 20161023PF also had a good root rating, but had considerable foliar symptoms. 20151044PFHO and 20151046PFHO had no foliar symptoms and very little storage rot, so the poor root rating may be related to inherently poor root shape and not a lack of BNYVV resistance. Twenty-six of the entries had resistance to fungal rots in storage, because they were not different from 20161014HO and Check 3. Some entries may serve as a starting point for identifying additional sources of resistance to BNYVV and storage rots
Temporal changes in 18O and 15N of nitrate nitrogen and H2O in shallow groundwater: Transit time and nitrate-source implications for an irrigated tract in southern Idaho
Get PDFIntensive irrigated agriculture in semiarid southern Idaho contributes to nitrate loads in shallow groundwater. To determine the temporal character and source of leached nitrate and the dominant soil N cycling process involved, we measured stable isotope ratios of nitrate (15N-NO3,18O-NO3) and water (2H-H2O,18O-H2O) in 1) tunnel drain and irrigation waters during 2003-07 and 2) leachate from incubated urea- and manure-amended soil endmembers. The 18O-H2O time series revealed an 8 to 13 month lag between peak values for irrigation water (the primary source of recharge) and those of tunnel drains, indicating the likely residence time for water in the shallow groundwater. Correlations of tunnel water 18O-NO3 and 18O-H2O with previous-year mean annual and summer precipitation, and reservoir storage factors confirmed the approximate year-long residence time. Eight of ten tunnel waters (categorized hereafter as Group I) had 15N-NO3 and 18O-H2O compositions of +6.3 ± 0.6 (± Std. Dev.) and -5.9 ± 0.7, respectively. Nitrate 15N-NO3 and 18O-H2O compositions of tunnel waters plotted between those of urea-amended soil (4.6 ± 0.5 and -4.9 ± 1.4), manure-amended soil (13.4 ±1.3 and -4.4 ± 1.2), and regional groundwater endmembers. A dual-isotopic element, three-source, simple linear mixing model indicated that, on average, 1.5 times more N is sourced from fertilizer and fixed N than animal waste. The dominant N-cycling process in the system at the scale observed here is the nitrification of NH4-N derived from applied fertilizer and manure, whereas denitrification has a minor influence. Increased knowledge of N cycling in both the vadose zone and shallow groundwater can improve nutrient management and cropping efficiency in the irrigation tract