Changes in light fraction soil organic matter and in organic carbon and nitrogen in compost amended soils

Organic vegetable growers can use compost to supply crops with nutrients and increase soil organic matter (OM), but little information is available about the transformations of compost OM over time in organically managed systems. This study examined light fraction soil organic matter (LFSOM) and organic carbon (C) and nitrogen (N) in organically and conventionally managed snap bean cropping systems (continuous beans (CB) and a fully phased beans/fall rye rotation (BR)) following three years of fertility treatments (1x and 3x compost, and 1x synthetic fertiliser, where 1x provided 50 kg ha-1 N). Light fraction C and N increased with compost amendment, with the C:N ratio significantly lower in composted plots than in synthetically fertilised plots. Rotation and weeding method played no role in the composition of LFSOM, or the percentage of LFSOM making up whole soil organic C or N. Light fraction N and C roughly doubled in the 1x compost plots over the three years, compared with synthetically fertilised plots, but was only 2.5 times higher in 3x compost plots. While the addition of 13 t ha-1 C increased whole soil C by 5.6 Mg ha-1, tripling the amount of added C raised whole soil C by 9.9 Mg ha-1. 1x and 3x compost increased whole soil N by 20 and 33%, respectively, compared with the 1x synthetically fertilised plots. The 3x compost treatment only, by reducing bulk density, improved soil physical properties

Season-long supply of plant-available nutrients from compost and fertiliser in a long term organic vs. conventional snap bean rotations experiment

In Canada, stockless organic vegetable cropping systems may use compost for fertility. However, information to guide growers about when nutrients become available in the soil over the growing season is lacking. Detailed analysis of plant nutrient supply was conducted over three years in a multi-site rotations experiment using two cropping sequences. The experiment compared conventional fertility treatment (synthetic fertiliser (1x N)) with organic treatments (annual compost amendment at a low (1x N) and a high rate (3x N)). Plant-available soil nutrients were captured using sequential two-week burials of ion exchange membranes. Ions were eluted and quantified. Variation in nutrient supply over time, and effects attributable to crop rotation and fertility regime were evaluated with analysis of variance and of principal components. Results showed season-long supply of plant nutrients was more affected by year than fertility regime or rotation, even in composted plots where large residual effects were expected. Synthetic fertiliser and 1x compost resulted in very similar seasonal plant nutrient supplies. While 3x compost caused some significant changes, the gains in plant nutrient supply was modest enough to suggest little or no advantage in this one respect to warrant the cost of amending at greater than the 1x rate

Comparison of Volatile Compounds Contributing to Flavor of Wild Lowbush (Vaccinium augustifolium) and Cultivated Highbush (Vaccinium corymbosum) Blueberry Fruit Using Gas Chromatography-Olfactometry

The flavor of blueberry fruit products is an important parameter determining consumer satisfaction. Wild lowbush blueberries are primarily processed into products, but their flavor chemistry has not been characterized. The objective of this study was to characterize the aroma chemistry of lowbush blueberries and compare it with that of highbush. Aroma volatiles of lowbush blueberries from four Canadian provinces and five highbush blueberry cultivars were isolated using headspace solid-phase microextraction (SPME) and characterized using gas chromatography-olfactometry (GC-O) and 2-dimensional gas chromatography-time of flight-mass spectrometry (GC×GC-TOF-MS). Lowbush fruit volatiles were composed of 48% esters, 29% aldehydes and 4% monterpenoids compared to 48% aldehydes, 26% monoterpenoids and 3% esters in highbush fruit. Twenty-three aroma-active peaks were identified in lowbush compared to forty-two in highbush fruit using GC-O. The most aroma-active compounds in lowbush fruit were ethyl 2-methylbutanoate, methyl 2-methylbutanoate, methyl 3-methylbutanoate, ethyl 3-methylbutanoate and ethyl propanoate compared to geraniol, (Z)-3-hexen-1-ol, 1-octen-3-one, α-terpineol and linalool in highbush fruit. The aroma volatile composition was more consistent among lowbush fruit samples than the five highbush cultivars. Aroma-active GC-O peaks were described more frequently as “floral”, “fruity”, “sweet” and “blueberry” in lowbush than in highbush fruit. Results suggest wild lowbush blueberries would provide “fruitier” and “sweeter” flavors to food products than cultivated highbush fruit

Comparative transcriptome expression analysis in susceptible and resistant potato (Solanum tuberosum) cultivars to common scab (Streptomyces scabies) revealed immune priming responses in the incompatible interaction.

Common scab disease in potato has become a widespread issue in major potato production areas, leading to increasing economic losses. Varietal resistance is seen as a viable and long-term scab management strategy. However, the genes and mechanisms of varietal resistance are unknown. In the current study, a comparative RNA transcriptome sequencing and differential gene signaling and priming sensitization studies were conducted in two potato cultivars that differ by their response to common scab (Streptomyces scabies), for unraveling the genes and pathways potentially involved in resistance within this pathosystem. We report on a consistent and contrasted gene expression pattern from 1,064 annotated genes differentiating a resistant (Hindenburg) and a susceptible (Green Mountain) cultivars, and identified a set of 273 co-regulated differentially expressed genes in 34 pathways that more likely reflect the genetic differences of the cultivars and metabolic mechanisms involved in the scab pathogenesis and resistance. The data suggest that comparative transcriptomic phenotyping can be used to predict scab lesion phenotype in breeding lines using mature potato tuber. The study also showed that the resistant cultivar, Hindenburg, has developed and maintained a capacity to sense and prime itself for persistent response to scab disease over time, and suggests an immune priming reaction as a mechanism for induced-resistance in scab resistant potato cultivars. The set of genes identified, described, and discussed in the study paves the foundation for detailed characterizations towards tailoring and designing procedures for targeted gene knockout through gene editing and phenotypic evaluation

High risk of alcohol-impaired driving in adults with comorbid alcohol and substance use disorders in the U.S. population

Objective: Alcohol-impaired driving is a significant source of injury and morbidity in the United States. People with alcohol use disorder (AUD) are more likely to drive while impaired by alcohol than their nonclinical counterparts. Less is known about rates of impaired driving in people with AUD and a comorbid substance use disorder (SUD). The current study examined the association among AUD, other SUDs, and alcohol-impaired driving in a nationally representative sample of adults in the United States. Method: Data were from the National Epidemiologic Survey on Alcohol and Related Conditions (NESARC-III; n = 36,309). AUD and SUD diagnoses according to DSM-5 criteria were determined using the Alcohol Use Disorder and Associated Disabilities Interview Schedule-5. We compared rates of past-year alcohol-impaired driving in people with AUD, another SUD (i.e., cannabis use disorder, stimulant use disorder, opioid use disorder), or AUD comorbid with another SUD against those with no past-year AUD or SUD diagnoses. Results: People with AUD had increased odds (adjusted odds ratios [AORs] = 15.85–28.27) of past-year alcohol-impaired driving behavior compared with past-year drinkers with no AUD or SUD. Although other SUDs per se were not consistently associated with increased odds of these behaviors (AORs = 0.28–4.07), people with AUD comorbid with SUD showed comparatively higher odds of these behaviors (AORs = 30.46–93.97). These effects held even when alcohol use quantity/frequency and AUD severity were controlled for. Conclusions: People with AUD and a comorbid SUD are at high risk for alcohol-impaired driving. More research is needed to understand the factors mediating increased odds of driving while impaired in people with substance use comorbidities, especially considering societal movement toward cannabis legalization. (J. Stud. Alcohol Drugs, 80, 114–119, 2019)

Influence of culture media, pH and temperature on growth and bacteriocin production of bacteriocinogenic lactic acid bacteria

Abstract There has been continued interest in bacteriocins research from an applied perspective as bacteriocins have potential to be used as natural preservative. Four bacteriocinogenic lactic acid bacteria (LAB) strains of Lactobacillus curvatus (Arla-10), Enterococcus faecium (JFR-1), Lactobacillus paracasei subsp. paracasei (JFR-5) and Streptococcus thermophilus (TSB-8) were previously isolated and identified in our lab. The objective of this study was to determine the optimal growth conditions for both LAB growth and bacteriocins production. In this study, various growth conditions including culture media (MRS and BHI), initial pH of culture media (4.5, 5.5, 6.2, 7.4 and 8.5), and incubation temperatures (20, 37 and 44 °C) were investigated for LAB growth measured as optical density (OD), bacteriocin activity determined as arbitrary unit and viability of LAB expressed as log CFU ml−1. Growth curves of the bacteriocinogenic LAB were generated using a Bioscreen C. Our results indicated that Arla-10, JFR-1, and JFR-5 strains grew well on both MRS and BHI media at growth temperature tested whereas TSB-8 strain, unable to grow at 20 °C. LAB growth was significantly affected by the initial pH of culture media (p < 0.001) and the optimal pH was found ranging from 6.2 to 8.5. Bacteriocin activity was significantly different in MRS versus BHI (p < 0.001), and the optimal condition for LAB to produce bacteriocins was determined in MRS broth, pH 6.2 at 37 °C. This study provides useful information on potential application of bacteriocinogenic LAB in food fermentation processes

Cultural practices to improve malt barley quality in the Northeast with focus on the craft sector

Demand is increasing for locally grown malt barley (Hordeum vulgare L.) in northeastern North America driven primarily by growth in the craft beer sector. A multi-site experiment was conducted to evaluate how variety (V), seeding rate (S) and nitrogen fertilizer (N) affect malt quality in the northeast. Two barley varieties (Cerveza and Newdale), two seeding rates (200 and 400 seeds m-2), and five rates of actual applied nitrogen fertility (0, 30, 60, 90, and 120 kg ha-1) were tested at Charlottetown, PE, Ithaca, NY, Princeville, QC, and New Liskeard and Ottawa, ON. Basic agronomic data were collected from all environments including yield, thousand kernel weight and hectoliter weight. Barley of suitable quality was micromalted and subjected to malt quality analysis. Both V and S resulted in small effects on malt quality, however N had the greatest effect on most measured variables. Increased rates of N application resulted in increased yield, hectoliter weight, and thousand kernel weight, but had a negative effect on most quality traits, especially with increased protein content, reduced fine extract, Kolbach Index and friability, and increased wort beta-glucans. This study shows that for most years at most sites, it is possible to achieve malt quality in the Northeast, however excessive protein and the prevalence of pre-harvest sprout damage are the main barriers. The results of this study have implications for increased malt barley production for the craft sector as well as potential access to commodity markets for northeastern producers.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Yield and nutritive value of grazed complex legume-grass mixtures under increasing N application rates

Complex pasture mixtures are advantageous, but little information exists on the best forage species and nitrogen (N) management in eastern Canada. We compared under mob stocking four complex mixtures of one of two legume species [alfalfa (Medicago sativa L.) and birdsfoot trefoil (Lotus corniculatus L.)] plus one of two grass mixes [No. 1 — timothy (Phleum pratense L.), meadow fescue (Schedonorus pratensis (Huds.) P. Beauv.), reed canarygrass (Phalaris arundinacea L.), and Kentucky bluegrass (Poa pratensis L.); No. 2 — tall fescue (Schedonorus arundinaceus (Schreb.) Dumort., nom. cons.), meadow bromegrass (Bromus biebersteinii Roem. and Schult.), reed canarygrass, and Kentucky bluegrass] under three N application rates at three sites over the first three post-seeding years. Legume species had little effect on most forage attributes mainly because of their low contribution to forage dry matter (DM) yield (30%.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Red Clover Varieties with Nitrogen Fixing Advantage During the Early Stages of Seedling Development

Plant and environmental factors affect root nitrogen (N) exudation dynamics in legumes. To better understand the genotypic variability and plant factors affecting root N release nodulation, plant growth, tissue N content, and root N exudation of six (three diploid and three tetraploid) red clover (Trifolium pratense L.) varieties were evaluated under controlled environmental conditions during the first eight weeks of plant growth after rhizobia inoculation. Genotypic differences were found for nodulation, plant dry weight, leaf area, root attributes (root length, surface area, volume, and diameter), shoot and root N concentration, and N content. Genotypic differences were found for root exudate N content in terms of NO3--N, NH4+-N, and dissolved organic N (DON). In general, root exudate inorganic N content was greater in tetraploid varieties than in the diploids throughout the growth period. Root exudate DON content was greater than the inorganic N content. The NO3--N content in root exudate was positively correlated with root growth attributes and root N concentration while, NH4+-N content was positively correlated with nodule number. Root exudate DON positively correlated with shoot N concentration and average nodule dry weight. These results highlight the existence of genotypic differences among red clover varieties for plant morphological factors affecting root N release during the early stages of plant development.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Tracking the development of the superficial scald disorder and effects of treatments with diphenylamine and 1-MCP using an untargeted metabolomic approach in apple fruit

Superficial scald is a physiological storage disorder that significantly reduces the marketability of apple fruit. To gain fundamental knowledge about the biochemical pathways leading to the development of the disorder and mechanisms of treatments for prevention, an untargeted metabolomics experiment employing liquid chromatography and mass spectrometry with data independent acquisition was performed. Metabolomic changes of two apple cultivars ‘Cortland’ and ‘Red Delicious’ with scald development and scald control treatments, using diphenylamine and 1-MCP, at 0–1 °C for up to 7 months was investigated. In total, 833 features/compounds were analyzed, and among them 59 were found to change significantly in controls involved in scald development, and in response to DPA and 1-MCP treatments. Our results provide new evidence that metabolites in association with phenylpropanoid metabolism, antioxidant and redox systems, and amino acid metabolism are related closely to scald development and response to potential treatments