Bromide concentrations in agronomic crops following methyl bromide fumigation in southeastern Idaho

Methyl bromide (MeBr) is a fumigant used to sterilize fields to control quarantine pests that are restricted due to its detrimental atmospheric effects. Bromide (Br-) is generally found in small amounts. Degradation of injected MeBr produces crop available Br-. Up to four applications of MeBr were used southeastern Idaho fields to combat the pale cyst nematode. Information regarding uptake and partitioning of Br- following MeBr application in agronomic crops in the region was unavailable. Research determined background concentrations of Br- in alfalfa (Medicago sativa, L.), barley (Hordeum vulgare, L.), corn (Zea mays, L.), potato (Solanum tuberosum, L.), and wheat (Triticum aestivum, L.) compared to MeBr-treated fields. Br- concentrations were log transformed. Study background Br- concentrations ranged from nondetectable (ND) to 33 mg Br- kg-1; vegetative tissue concentrations were greater than reproductive. Nearly all crops grown in MeBr-treated fields had greater Br- concentrations than background. Background alfalfa Br- concentration was 33 mg kg-1 in baled tissue compared to 118 mg Br- kg-1 from a MeBr-treated field. Br- concentration in green alfalfa decreased from 80 to 36 mg Br- kg-1 at the final cutting in a MeBr-treated field, where time after application has been shown to decrease crop Br- concentrations. Small grains had low Br- concentrations in reproductive tissue compared to vegetative, and corn stover (13 mg Br- kg-1) was low relative to small-grain straw (107 mg Br- kg-1) in the MeBr-treated field. Crop selection following MeBr applications should consider the likelihood of elevated Br- concentration for the plant fractions intended end-use

Fertilizer nitrogen recovery of irrigated spring malt barley

Well defined nitrogen (N) management in irrigated two-row malting barley (Hordeum vulgare L.) is critical for yield, quality, and to minimize negative environmental impacts. Data on fertilizer N recovery efficiency (FNRE) and the fate of fertilizer-N in the soil is lacking for irrigated malting barley. The objective of this study was to determine uptake and partitioning of 15N labeled urea in the plant and soil. Mimicking common regional practices, urea was either surface applied or incorporated at a total N rate of 214 kg N ha-1 at planting. Three common malt cultivars were grown, and samples were collected four times during the growing season (Feekes growth stages 4/5, 10.0, 11.2, and 11.4). Barley plants at Feekes 11.2 and 11.4 were separated into plant (culms plus leaves) and spikes. Plant N accumulation was lowest at Feekes 4/5 and increased to a maximum at Feekes 11.2 where FNRE was greatest at Feekes 10.0. Nitrogen was redistributed from the plant to the spike from Feekes 11.2 to 11.4. The barley plant FNRE averaged 43% at maturity. The total soil-plant FNRE for the surface application was 66%, which was less than the incorporated fertilizer FNRE of 77%. Results from the current study provide evidence of the increased FNRE of incorporated applications in high-input barley production systems as well as similar recovery efficiency as compared to previous work under higher-yielding conditions. Results can be used to refine growing practices to ensure agronomically and environmentally sound management

Barley yield and malt-characteristics as affected by nitrogen and final irrigation timing

Idaho is one of the largest malt barley (hordeum vulgare, L.) producers in the United States. In Idaho, barley is a major commodity in the irrigated production area of the semi-arid Snake River Plain of the southern part of the state. Grain quality and malting characteristics in addition to yields are key factors influencing production. While the importance of available nitrogen (N) and irrigation have been established, the interaction of these inputs has not been deeply investigated. To address this, we conducted research at the Kimberly R&E Center, ID arranged in a RCBD to determine yield and quality as affected by N application rate (0, 56, 112, 168 kg N ha-1) and irrigation cutoff timings with irrigation managed at 100% evapotranspiration (ET) until the crop growth stages of, F10: Feekes 10.0; F11.2: Feekes 11.2; and +7F11.2: +7d Feekes. Both N fertilization and irrigation cutoff timing affected tested grain, straw, and malt characteristics. Only minor differences were measured between F11.2 and +7F11.2 irrigation cutoff timings indicating irrigations past F11.2 were generally not beneficial. Application of N at 56 kg N ha-1 maximized yield in the study but greater predicted yields were determined from the fitted model and did not result in grain or malt quality characteristics outside of the range acceptable for malting. Results warrant further investigations into increased N applications to achieve higher yields while maintaining malt quality. Grain protein was well correlated to malt characteristics under varying N rates and irrigation cutoff timings. The results of this study provide evidence of the effects of irrigation cutoff timing and N management on grain yield and quality, barley straw, and malt characteristics that are critical for establishing appropriate fertilizer-N recommendations and irrigation management strategies in malting barley in Idaho

Intercropping in maize silage versus solo-seeding for alfalfa establishment in Wisconsin and Idaho

Alfalfa (Medicago sativa L.) intercropping with maize (Zea mays L.) silage is being developed in the northern United States to improve the profitability and environmental sustainability of forage production. This study, conducted under rainfed conditions inWisconsin and semiarid irrigated conditions in Idaho, compared the establishment of alfalfa and dry matter yield of four intercropping systems to three conventional systems. The former systems included alfalfa interseeded at planting or the vegetative emergence (VE) stage of maize and grown with or without prohexadione growth retardant. The latter systems included alfalfa seeded in spring, summerseeded after barley (Hordeum vulgare L.), or late summer-seeded after maize silage. Spring seeded and interseeded alfalfa inWisconsin also received foliar fungicide and insecticide during establishment. During alfalfa establishment, yield of intercropped maize silage was 1.8- to 4.4-fold greater than spring-seeded alfalfa. Compared to spring-seeded alfalfa, interseeded alfalfa had similar or somewhat lower stand density but similar first cut yield the following year, provided that intercropped maize was harvested near September 1 to allow ample alfalfa fall regrowth. Shifting interseeding from maize planting to the VE stage decreased early-season alfalfa growth, but improved maize silage yield, with minor effects on alfalfa fall growth, stand density, and first cut yield. Prohexadione application had little impact on establishment or yield of interseeded alfalfa. While having high plant density, alfalfa seeded after barley or especially maize had less fall growth and low first cut yield. Overall, alfalfa establishment and yield of intercropping systems compared favorably with conventional systems

Ammonia volatilization from fertilizer sources on a loam soil in Idaho

Optimizing crop nitrogen (N) uptake while minimizing ammonia (NH3) volatilization from N-fertilizer sources is a critical part of agricultural best management practices. Urea is the most widely used N-fertilizer but also one of the most susceptible to losses as NH3. Fertilizer source and additives can be used to reduce NH3 volatilization. Specifically, urease inhibitors e.g., N-(n-butyl) thiophosphoric triamide (NBPT) can reduce NH3 volatilization from urea. Novel fused ammonium sulfate nitrate (ASN) products have recently been developed as another potential alternative N-fertilizer source but have not been studied widely. A field study was performed to quantify NH3 volatilization from the newly available ASN fertilizer as compared to various N-fertilizers (ammonium sulfate (AS) and urea) including urea treated with the urease inhibitor NBPT in an alkaline calcareous loam soil in Idaho. Further, we assessed NH3 volatilization from surface applied and incorporated N-fertilizers from these various N sources. Untreated surface-applied urea volatilized the highest amount of NH3, whereas incorporation of N-fertilizers was effective in reducing volatilization as compared to untreated surface applied urea. Our study indicated that the N-fertilizer sources (AS, ASN, and Urea-NBPT) were equally effective in reducing NH3 volatilization when compared to surface applied urea. Our study will help refine N-fertilize management under multiple field situations and traditional management practices of crop producers in the western United States. Further, site-years and study locations would be needed to provide evidence of the effectiveness of ASN in reducing NH3 volatilization under a wider range of soil and environmental conditions

Deficit irrigation effects on adjunct and all-malt barley yield and quality

Semi-arid regions are reliant on supplemental irrigation to produce large-yielding and high-quality malt barley (Hordeum vulgare, L.). Current and widespread drought in the western United States is of particular concern as surface and ground water reductions are occurring that affect irrigation water availability. Implementing a seasonal deficit of water compared to evapotranspiration (ET) is a potential mechanism to reduce water usage if yield and quality can be maintained. Research was conducted at the University of Idaho Aberdeen R&E Center, Aberdeen, Idaho on the effects of deficit irrigation on yield, grain quality, and malt characteristics of barley. Five genotypes were selected to represent those used for large-scale adjunct brewing and those targeted at the all-malt craft industry. Irrigation was managed at three rates (100%, 75%, and 50%) of estimated crop evapotranspiration (ETc) using a sprinkler irrigation system. Total aboveground dry matter (TDM) was not affected by irrigation until soft dough (Feekes 11.2; F11.2). Yield was similar within a genotype with irrigation reduction from 100% ETc to 75% ETc. Averaged across genotypes, yields were 6936 kg ha-1 at 100% ETc and 6297 kg ha-1 at 75% ETc. At 75% ETc, protein was just below the adjunct target of 130 g kg-1, excluding Harrington, and no genotype stayed below 120 g kg-1, the all-malt target. Deficit irrigation is promising, particularly for adjunct brewing; however, expected changes to malting quality profiles must be understood and varietal selection, breeding advancements, and/or changes to malting criteria may be needed for successful implementation of deficit irrigation

Risk factors for transport-related problem behaviors in horses: A New Zealand survey

Transport-related problem behaviors (TRPBs) are common in horses and can cause injury to both the horses and their handlers. This study aimed to identify possible risk factors for TRPBs to inform approaches to mitigate TRPBs incidence and enhance horse welfare. An online cross-sectional survey was conducted to explore the prevalence of TRPBs and their association with human-, training-and transport management-related factors in New Zealand. The survey generated 1124 valid responses that were analyzed using descriptive statistics, and logistic regression analyses. Having at least one horse with TRPB was reported by 249/1124 (22.2%) respondents during the two previous years. Of these, 21/249 (8.4%) occurred during pre-loading, 78/249 (31.3%) during loading, 132/249 (53.0%) while travelling, and 18/249 (7.3%) during unloading. Our findings indicate that the use of negative reinforcement and positive punishment as training methods, using a whip or food for loading, and travelling in a straight load trailer/float while offering food were associated with a higher likelihood of TRPBs. Cross-sectional studies cannot determine causality and findings should be interpreted with caution, and evaluated in further experimental studies. The authors suggest that education on appropriate training methods for transport, and vehicle selection may mitigate the risk for TRPBs in horses

Predicting nitrogen mineralization from long term application of dairy manure in a semiarid cropping system

Approximately 37% of US milk production occurs in semiarid regions providing an opportunity to recycle manure nutrients through a variety of cropping systems. Accurate prediction of nitrogen (N) mineralization is critical to determine manure application suitability in intensive irrigated agriculture as many crops in the region have quality parameters that are sensitive to N. Research was conducted in south central Idaho to evaluate N mineralization via a buried bag methodology to develop a predictive N-mineralization model. The study was arranged in a randomized complete block design with manure application rates of 18, 36, and 52 Mg ha-1 both annually and biennially with synthetic fertilizer and untreated check treatments. The crop rotation included small-grain and broadleaf crops. Greater manure applications resulted in an increase in soil organic matter (SOM), total nitrogen (TN), and nitrate (NO3-N) at the culmination of the study. Nearly five-times as much N was mineralized annually in the 0 to 30 cm depth as compared to the 30 to 60 cm depth. Increased rates of mineralization for each kg of added N occurred in years when residue from broadleaf crops (slope = 0.17) was applied as compared to small-grain years (slope = 0.07). Stepwise modeling determined that the most predictive model for seasonal N mineralization (R2 = 0.79) included manure N, residue N, soil organic matter, and electrical conductivity. These results allow preplant N mineralization estimation and will prove critical for managing manure in semiarid regions for agronomic, economic, and environmentally sound crop production