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Greenhouse gas emissions from an irrigated cropping rotation with dairy manure utilization in a semiarid climate
Full text linkGreenhouse gas (GHG) emissions data from irrigated cropping systems utilizing dairy manure are needed in semiarid western regions. The objectives of this field study were to (i) determine the effect of synthetic N fertilizer (urea), enhanced-efficiency synthetic fertilizer (SuperU), composted dairy manure, dairy manure applications (fall and spring applied), and a control (no fertilizer or manure) on GHG losses over the growing season and overall global warming potential (GWP) and (ii) evaluate the influence of irrigation and field/crop management practices on GHG fluxes. The treatments were not applied to alfalfa (2017) but were applied to corn (2018; except SuperU) and barley (2019). Cumulative N2O-N losses over the 3-year rotation ranged from 2.8 to 5.2 kg/ha, with the fall and spring manure losing the greatest amounts of N2O-N. Emission factors indicated that -1.5 to 0.79% of the total N applied was lost as N2O-N during the growing seasons. Cumulative losses of CO2-C and CH4-C over the rotation were on average 12,170 and -0.77 kg/ha, respectively, with no significant differences among the treatments. Major N2O-N pulses were associated with early-season irrigation events and incorporation of fertilizer and manure, but overall fluxes tended to increase during the summer months when soil temperatures were highest. When accounting for increases in soil organic carbon (SOC) over the three growing seasons, the net GWPs were determined to be negative for the compost (-35.4), fall manure (-130.4), and spring manure (-48.9) treatments. As a result, these manure treatments should be considered as an alternative to synthetic N fertilizer use in southern Idaho due to their ability to increase SOC and help reduce agricultural climate impacts, while maintaining high crop yields
A roadmap to durable BCTV resistance using long-read genome assembly of genetic stock KDH13
Full text linkBeet Curly Top (BCT) is a viral disease which negatively impacts crop productivity for sugar beet growers and the sugar beet industry in the western US and dry regions worldwide. Current varieties exhibit little genetic resistance to the Beet Curly Top Virus (BCTV), suggesting there is a large potential for improvement. KDH13 (PI 663862) is a double haploid line created from a population (C762-17/PI 560130) which segregates for BCT resistance and was identified as genetic stock for the improvement of sugar beet resistance to BCTV. PacBio sequences were generated and assembled to better define the content and organization of variation within the KDH13 genome and to provide resources to identify specific variation underpinning durable genetic resistance. Using ab-inito predicted proteins as anchors, the assembled KDH13 contigs were placed in a more contiguous order using the EL10.1 reference genome, which leveraged Bio-Nano optical maps and Hi-C proximity information for chromosome level scaffolding. In total, 4,681 (75%) of the 6,245 contigs were placed in the order and orientation of the EL10.1 genome. The anchored contigs represented 502,929,268 bp (87.7%) the KDH13 genome assembly. An F1 hybrid, and parental lines KDH13 (resistant) and KDH19-17 (susceptible) were sequenced using Illumina technology in order to characterize the SNP, indel and structural variation between parental lines and allow for a more detailed investigation into causal variation linked to important phenotypes. In total, 11,675,321 variants were detected, 3,377,004 SNP and 602,704 indels contained the ability to discriminate between the two parents. KDH13 contained 1,642,083 SNP and 308,615 indels identified as unique. This information represents a high-density marker dataset distributed across the beet genome and can be used to track genomic segments in populations where KDH13 is used as parental material to improve BCTV resistance
Simulating soil nitrogen fate in irrigated crop production with mature applications
Full text linkDairy manure is commonly applied to irrigated agricultural crops in the Magic Valley Region of southern Idaho, which has reported to impact the quality of surface and ground water. In this study, we used the Root Zone Water Quality Model (RZWQM2) to provide information about the long-term implications of manure applications. RZWQM2 was first calibrated and validated using 4 years of data from a long-term study with annual and biennial manure application rates of 18 Mg ha-1, 36 Mg ha-1, and 52 Mg ha-1, along with a control and conventional fertilizer treatment for crop yield, soil water and soil N. The 4-yr crop rotation was spring wheat (2013), potato (2014), spring barley (2015), and sugar beets (2016). RZWQM2 simulated soil water content, crop yield, total soil nitrogen, and soil nitrogen mineralization effectively as PBIAS and RRMSE for soil water content and crop yields were within the acceptable range (± 25% for PBIAS and <1.0 for RRMSE). Nitrate in the soil profile was overestimated, however in the acceptable range for the validation treatments. The calibrated model was then run for 16 years by repeating the management practices of the 4-year scenarios (4 crop rotations) for all treatments and 24 years for the 52 T Annual treatment (6 crop rotations). The 16-year simulation results showed that nitrogen seepage from annual manure treatments (for example, 18 T Annual vs 18 T Biennial) was 2.0 to 2.3 times higher than the nitrogen seepage from the biennial manure treatments. Increasing manure applications from 18 T Annual to 52 T Annual increased N seepage an average of 3.2 times for the 16-year rotation. Nitrogen seepage increased dramatically in rotations 3 and 4 compared to rotations 1 and 2 in the sixteen-year simulation. The 24-year simulation results showed after manure had been applied annually for 16 years and then applications terminated, the amount of N seepage returned initial levels in 8 years. In conclusion, to maintain clean ground water, manure applications would be best applied biennially and high applications should be discouraged
Soil organic carbon dynamics in semi-arid irrigated cropping systems
Full text linkThe insufficient characterization of soil organic carbon (SOC) dynamics in semi-arid climates contributes uncertainty to SOC sequestration estimates. The opportunity exists to improve estimates of SOC dynamics in irrigated semi-arid croplands by studying research locations in south-central Idaho. This study intended to estimate changes in SOC (0-30 cm depth) due to variations in manure management, tillage regime, adoption of winter cover, and crop rotation. Empirical data from three research locations was also used to drive denitrification decomposition (DNDC) models in a “default” and calibrated capacity as well as forecast SOC levels until 2050 under “high” and “low” emissions future climate scenarios. Empirical data indicates: (i) increasing C input results in more rapid increases in SOC; (ii) no effect (P = 0.51) of winter triticale on SOC after 3 years; (iii) SOC accumulation (0.6 ± 0.5 Mg ha-1 yr-1) under a dairy forage rotation of corn-barley-alfalfax3 and no change (P = 0.905) in a commercial rotation of wheat-potato-barley-sugarbeet; (iv) manure applied annually at rate 1X is not significantly different (P = 0.75) from biennial application at rate 2X; and (v) no significant effect of manure application timing (P = 0.41, fall vs spring). The DNDC model simulated empirical SOC and biomass C measurements adequately in a default capacity, yet specific issues were encountered. The calibration improved model fit however simulation of soil water contents and actual evapotranspiration remained unacceptable. By 2050, model forecasting suggested: (i) SOC stock was ~ 1 % different between future emissions scenarios; (ii) triticale cover resulted in SOC accrual (0.5 – 0.27 Mg ha-1 yr-1); (iii) when manure is applied, conventional tillage regimes are favored; and (iv) manure applied treatments accrue SOC fitting a quadratic relationship (all R2 > 0.85 and all P < 0.0001), yet extending the simulation to 2100 indicated no equilibrium was realized. It is possible that under very large C inputs that C sequestration is inaccurately favored by DNDC which may influence “NetZero” C initiatives. Our findings improve upon knowledge of SOC dynamics in semi-arid irrigated cropping systems and could aid DNDC model development endeavors
DataMan: A global dataset of nitrous oxide and ammonia emission factors for excreta deposited by livestock and land-applied manure
Full text linkNitrous oxide (N2O), ammonia (NH3) and methane (CH4) emissions from the manure management chain of livestock production systems are important contributors to greenhouse gases (GHG) and NH3 emitted by human activities. Several studies have evaluated manure-related emissions and associated key variables at regional, national or continental scales. However, there have been few studies focusing on these emissions using a global dataset. An international project was created (DataMan) to develop a global database on GHG and NH3 emissions from the manure management chain (housing, storage and field), to identify key variables influencing emissions, and ultimately to refine EFs for future national GHG inventories and NH3 emission reporting. This paper describes the “field” database that focuses on N2O and NH3 EFs from land-applied manure and excreta deposited by grazing livestock. We collated relevant information (EFs, manure characteristics, soil properties and climatic conditions) from published peer-reviewed research, theses, conference papers and existing databases. The database, containing 5,632 observations compiled from 184 studies, was relatively evenly split between N2O and NH3 (56% and 44% of the EF values, respectively). The N2O data were derived from studies conducted in 21 countries on five continents, with New Zealand, the UK, Kenya and Brazil representing 86% of the data. The NH3 data originated from studies conducted in 17 countries on four continents, with the UK, Denmark, Canada and the Netherlands representing 79% of the data. Wet temperate climates represented 90% of the total database. The DataMan field database is available online at http:// dataman.azurewebsites.net
Beet curly top resistance in USDA-ARS plant introduction lines, 2020
Full text linkThirty sugar beet (Beta vulgaris L.) USDA-ARS Plant Introduction (PI) lines and three commercial check cultivars were screened for resistance to Beet curly top virus (BCTV). The curly top evaluation was conducted at the USDA-ARS North Farm in Kimberly, ID which has Portneuf silt loam soil and had been in barley in 2019. The field was plowed and then fertilized and roller harrowed on 27 Mar. The germplasm was planted on 18 May. The plots were two rows 10-ft long with 22-in. row spacing and treatments were arranged in a randomized complete block design with six replications. The field was sprinkler irrigated, cultivated, and hand weeded as necessary. Plant populations were thinned to about 23,760 plants/A on 17 Jun. Plants were inoculated at the four- to six-leaf growth stage on 23 Jun with approximately six viruliferous (containing the following BCTV strains: California/Logan and Severe) beet leafhoppers (Circulifer tenellus Baker) per plant. The beet leafhoppers were redistributed three times a day during the first two days and then twice a day for five more days by dragging a tarp through the field. The plants were sprayed with Lorsban 4E on 7 Jul to kill the beet leafhoppers. Plots were rated for foliar symptom development on 13 Jul using a scale of 0 to 9 (0 = healthy and 9 = dead), with the scale treated as a continuous variable. Data were rank transformed and analyzed in SAS using the general linear model procedure (Proc GLM), and Fisher’s protected least significant difference (LSD; a = 0.05) was used for mean comparisons. The non-transformed means are presented in the table. Only results for 26 lines are reported in the table since 4 lines (6, 19, 20, and 21) did not grow. Curly top symptom development was uniform and no other disease problems were evident in the plot area. The resistant and susceptible checks performed as expected for the visual ratings. Statistically, 13 of the entries contain at least some minor resistance since their visual ratings were significantly lower than those for both susceptible checks. However, only entry 28 was not significantly different from the resistant check. Entry 28 along with entries with similar levels of resistance will be retested and, if resistance is confirmed, these lines will be considered for incorporation into the USDA-ARS germplasm improvement program as a source of resistance to BCTV
USDA-ARS plant introduction lines evaluated for rhizomania and storage rot resistance in Idaho, 2020.
Full text linkThirty sugar beet (Beta vulgaris L.) USDA-ARS Plant Introduction (PI) lines and five check cultivars were screened for resistance to Beet necrotic yellow vein virus (BNYVV), the causal agent of rhizomania, and to storage rot. The rhizomania evaluation was conducted at the USDA-ARS North Farm in Kimberly, ID which has Portneuf silt loam soil and had been in barley in 2019. In the spring the field was plowed and fertilized (110 lb N and 120 lb P2O5/A) and roller harrowed on 27 Mar 20. The germplasm was planted (density of 51,840 seeds/A) on 20 Apr. The plots were one row 10-ft long with 22-in. between-row spacing and arranged in a randomized complete block design with 6 replicates. The crop was managed according to standard cultural practices for southern Idaho. The trial relied on endemic field inoculum for rhizomania and storage rot development. The plots were rated for rhizomania foliar symptom (percentage of plants with yellow, stunted, upright leaves) development on 24 Aug. The plants were mechanically topped and hand harvested on 13-14 Oct. At harvest, ten roots per plot were rated for rhizomania symptom development using a scale of 0 to 9 (0 = healthy and 9 = dead; Plant Disease 93:632-638), with disease index (DI) treated as a continuous variable. At harvest, eight roots per plot were also placed in a mesh-onion bag and kept in an indoor commercial storage facility (temperature set point 34°F) in Paul, ID on 15 Oct. On 22 Feb 21, after 131 days in storage, the roots were evaluated for the percentage of root surface area covered by fungal growth or rot. Data were analyzed in SAS (Ver. 9.4) using the general linear model (Proc GLM) procedure, and Fisher’s protected least significant difference (a = 0.05) was used for mean comparisons. The root ratings were rank transformed prior to analysis, but the non-transformed means have been presented in the table.
Rhizomania symptom development was uniform and other disease problems were not evident in the plot area. The stand for four lines (6, 19, 20, and 21) was poor to non-existent. Thus only 26 PI lines were included in the table. The BNYVV susceptible check plots (Check 1 and Red beet) had 100% foliar symptoms and high root disease ratings. Resistant check 3 had 1% foliar symptoms and a low root rating which indicates that resistance based on two genes is holding up. Single gene resistance (Checks 2 and 4) had foliar ratings ranging from 8 to 13% indicating single gene resistance is not completely effective, but the root ratings were still good. Ten entries (2, 3, 4, 12, 15, 22, 27, 28, 29, and 30) had a level of BNYVV resistance similar to at least one of the resistant checks based on root ratings. Entry 11 was highly susceptible with a root rating worse than the sugar beet susceptible check. A number of the entries had resistance to fungal rots in storage, but only entry 4 performed well for all three variables. Some entries may serve as a starting point for identifying additional sources of resistance to BNYVV and storage rots
Optimizing irrigation water
Full text linkWhen applied properly, the synthetic organic polymer, polyacrylamide or PAM, can provide substantial water quality, infiltration, and water retention benefits to irrigated agriculture. To achieve peak performance, applications may need to be fine-tuned for individual circumstances. This article discusses how water-soluble PAM (WSPAM) and cross-linked PAM (XPAM) can be most effectively employed in irrigated agriculture. The form of WSPAM, method of application, and rate of application used in furrow irrigation will vary depending on local irrigation water quality and field soil properties. XPAM is comprised of WSPAM polymers cross-linked together to form a massive, porous product, which is not water soluble but can absorb >100+ times its weight in water. XPAM is added to soil to increase water retention and reduce water and nutrient leaching losses. Using XPAM in humid regions could be a challenge, since increased soil water retention during periods of surplus precipitation could create problems associated with excess water, slow soil drying/warming in spring, delayed tillage and planting. The use of XPAM in arid-land, irrigated agriculture may provide the most benefits because water deliveries to fields in these areas are intensively managed and can be limited or delayed
Experimental sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2019
Full text linkRhizomania 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, 7 experimental cultivars were screened by growing them in a sugar beet field infested with BNYVV in Kimberly, ID during the 2019 growing season in a randomized complete block design with 6 replications. At harvest on 7-8 October 2019, roots were dug and evaluated for symptoms of rhizomania and also placed in an indoor commercial sugar beet storage building. After 145 days in storage, samples were evaluated for surface rot, weight loss, and sucrose loss. Surface root rot ranged from 14 to 48%, weight loss ranged from 13 to 25%, sucrose losses ranged from 28 to 57%, and estimated recoverable sucrose ranged from 2,442 to 9,002 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
Beet leafhopper and BCTV strain survey
Full text linkScreening for resistance to Beet curly top virus (BCTV) in sugar beet suggests that at least some sources of resistance are strain specific. Also, beet leafhopper populations can vary by location and year. Thus, at the request of a sugar beet industry stakeholder, beet leafhopper populations in southern Idaho were tracked during the 2020 growing season in desert areas and sugar beet and dry bean fields in four southern Idaho counties. Samples were collected on a weekly basis from May through mid-September to assess all leafhoppers for population levels and the presence of BCTV strains. Crop plants from monitored fields were also assessed for the presence of BCTV strains. Beet leafhopper populations in Elmore Co. were present in at least double-digit numbers through most of the summer at all three sites. However, populations peaked in the Elmore desert (avg. 401 beet leafhoppers per 40 sq. inches) on 20 May, while populations in the bean field peaked in late Jun to mid-Jul (avg. 24) and the sugar beet field on 5 Aug (avg. 69). In the Twin Falls Co. desert, the beet leafhopper populations were low (high was an avg. of 3 in Aug) throughout the season. While the Twin Falls Co. sugar beet field peaked with an average of 27 beet leafhoppers on 22 Jul and the bean field peaked with an average of 4 beet leafhoppers on 15 Jul. In Minidoka Co. only a few beet leafhoppers were collected at all three sites late in the summer. In Bingham Co. beet leafhoppers at the desert and sugar beet sites were almost undetectable through the whole season. However, the Bingham Co. bean field had an average of 23 beet leafhoppers by 26 Aug. Preliminary data suggest two haplotypes (based on cytochrome oxidase gene) dominate the beet leafhopper population. Over the 19-week collection period, the horizontal card averaged 75% fewer beet leafhoppers than the vertical card. The BCTV strain and phytoplasma identification is currently a work in progress. Once all data are collected, the project will establish the BCTV strains for which host plant resistance is needed and the best time for when control of beet leafhoppers is necessary