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Lignocellulosic biomass is an important feedstock for the second generation bioenergy production. A sustainable supply of biomass feedstock having consistent composition is critical for a biorefinery. This requires a timely monitoring and estimation of the biomass yield and composition in the field. It is not clear if one can use the near infrared (NIR) vegetation canopy reflectance measured in the field and build a calibrate model to estimate biomass yield and nutrient contents (compositions) for the vegetation from vegetative growth through dormancy stages. In this study, the NIR canopy reflectance of a grass/legume mixture was measured in a field with a spectroradiometer with wavelength ranging from 400-2500 nm. The plants were then clipped, dried, and ground to measure the biomass yield, neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP). The measurements were conducted at the boot, peak growth, and at dormancy stages. Partial least significant regression (PLSR) models were built using data from each individual growth stage as well as all stages combined. Except for the yield model at peak growth stage and the NDF and ADF models at dormancy stage, models developed from each of the individual stages generally estimated the yield, CP, NDF, and ADF poorly, with R 2 CV ranging between -0.31 and 0.42. When data from all three growth stages were included, the accuracy of all models was greatly improved, with R 2 CV ranging between 0.77 and 0.80. Furthermore, multiple linear regression (MLR) models developed with 7–9 most significant wavelengths selected from 400-2500 nm estimated the yield, ADF, NDF, and CP equally well compared with the PLSR models. The estimates from MLR model showed strong correlations between the measured and estimated values, with R 2 of 0.72, 0.67, 0.78, and 0.66 for the yield, ADF, NDF, and CP, respectively. These results indicate that biomass feedstock yield and composition can be estimated by the in-situ NIR canopy reflectance using a multiple linear regression model with 7–9 wavelengths. Further calibration is needed to use the model to other geological locations. [ABSTRACT FROM AUTHOR]

Lack of crop rotation diversity and extensive tillage leaves the soil in many sugarbeet-based production systems vulnerable to wind erosion. Intercropping sugarbeet ( Beta vulgaris L.) with a living mulch is a practice that aims to protect sugarbeet seedlings from blowing soil and provide ecosystem services such as enhancing soil organic matter, reducing sedimentation in surface-irrigated farms, and improving soil biological activity. If managed improperly, nevertheless, the living mulch can compete with sugarbeet and reduce its production. Selection of an appropriate crop species along with timely termination are the two critical points that need to be researched in order to minimize the impact of living mulch on sugarbeet performance while still offering ecosystem services. A 4-yr field experiment was conducted to evaluate the effect of living mulch and its termination time on sugarbeet population, root yield, and purity. Over four years of the study, living mulch terminated at sugarbeet V2 growth stage had no significant effect on sugarbeet yield and quality. However, when living mulch termination was delayed to V4 and V6 growth stages, root yield declined by 17 and 14 Mg ha −1 , respectively, compared to 66.4 Mg ha −1 yield in the control. Living mulch had a positive impact on root quality traits by increasing sucrose concentration and decreasing root impurities (sodium, potassium, and amino-N concentration in the beet). The results indicated that planting sugarbeet with a living mulch can offer ecosystem services without negatively impacting sugarbeet productivity (recoverable sucrose yield) if terminated no later than V2 growth stage. [ABSTRACT FROM AUTHOR]

Damping-off and root rot are diseases of concern in chickpea (Cicer arietinum L.) production and can cause seedling loss, increase weed populations, and reduce yield. A complex of soilborne pathogens is responsible for damping-off and root rot in the Northern Great Plains. Species within this complex include Fusarium spp., Pythium spp., and Rhizoctonia solani. Currently, partially resistant cultivars and fungicide seed treatments are the most effective for control of damping-off and root rot. This study examined 25 chickpea cultivars and breeding lines with and without a fungicide seed treatment (fluxapyroxad, pyraclostrobin, and metalaxyl) for stand establishment and grain yield in field conditions. Experimental plots were located in dryland and irrigated fields at the Eastern Agriculture Research Center (EARC) in Sidney MT in 2020 and 2021, respectively. Stand counts were recorded three times to calculate area under disease progress curve (AUDPC). Yield, and protein content (only in 2021) was assessed after harvest. In 2021, pathogens were isolated from chickpea roots showing signs of root rot and identified as Fusarium solani. The results showed that the seed treatments effectively decreased soilborne disease development (75%–84%) and improved chickpea yield (11%–14%) in 2020 and 2021, and increased protein content (0.6%) in 2021. Different cultivars did not have a consistent impact on disease development and yield protection. NDC160166 and NDC160236 displayed consistently lower disease and higher yield and might be a future source of disease resistance. Yield of untreated seeds decreased and AUDPC increased for all cultivars/lines in both years. A negative correlation was also observed between protein content and chickpea yield in 2021. • The seed treatment (fluxapyroxad, pyraclostrobin, and metalaxyl) controlled chickpea soilborne diseases and improved yield. • Cultivars performed differently in seed yield, seed protein content, and disease development. • NDC160236 consistently displayed high yield potential. • NDC160049, NDC160133, NDC160146, NDC 160236, NDC160166 and Royal showed more tolerance to soilborne disease in 2020. • Fusarium solani was isolated and identified from chickpea root rot in 2021. [ABSTRACT FROM AUTHOR]

The promotion of dry pea ( Pisum sativum L.) and lentil ( Lens culinaris Medik.) production in cereal dominated cropping systems require identifying high yielding and widely adapted genotypes for a diverse range of environments. However, this information is rarely available in the semi-arid temperate region. We carried out two separate experiments consisting of seven genotypes of dry pea in 25 environments and eight genotypes of lentil in 16 environments to determine yield performance and stability. The results showed that environments (E) and genotypes (G) and interaction (G × E) effects were highly significant ( P < 0.0001) for both experiments. Average grain yield among genotypes varied from 2243 to 2680 and from 1229 to 1643 kg ha −1 for dry pea and lentil, respectively. The G × E accounted 5.4 and 15.8% of the total sum of square for dry pea and lentil experiments, respectively. The G × E effects were crossover type for both experiments revealing inconsistent performance of genotypes across environments. Based on interaction principal component analysis of G × E, the dry pea genotypes, Montech 4152 followed by SW Midas and DS Admiral showed combination of better yield performance and stability. Among the lentil genotypes, CDC Richlea followed by Avondale showed less fluctuation to environmental changes but produced similar yields compared with the high yielding lentil genotypes. Therefore, these dry pea and lentil genotypes can be recommended for cultivation in wide range of environments in the temperate semi-arid climates and similar ecologies. [ABSTRACT FROM AUTHOR]

Camelina ( Camelina sativa L. Crantz) is a promising bioenergy crop, but a sustainable production system for this crop has not yet been well developed. There is also concern about competing land use between crop productions for bioenergy or food use. One approach to overcoming this concern and developing sustainable production systems for bioenergy crops is potentially replacing the fallow period in wheat-based cropping systems with bioenergy crops. The agronomic and economic benefits of growing camelina in rotation with winter wheat were evaluated in a replicated rotation study from 2008 to 2011 in the Northern Great Plains (NGP), focusing on the effects on wheat yield and overall profitability of the cropping system. Average winter wheat yields were 2401 and 1858 kg ha −1 following camelina and barley, respectively, representing a 13.2 and 32.8% winter wheat yield reduction compared to the fallow–winter wheat rotation (2766 kg ha −1 ). Lower winter wheat yield in the alternative systems were offset by 907 kg ha −1 camelina and 1779 kg ha −1 barley yields. Economic analyses revealed that at existing market prices and production costs, the traditional fallow–winter wheat rotation provides greater net returns to growers due to substantially lower variable costs of the system. Scenario analyses that use more optimized, lower cost camelina production practices show that the net profits of camelina–wheat system could be closer to those in the fallow–wheat system. However, higher grain price and/or greater grain yield of camelina are essential to attract producers to include camelina in their cropping systems. Although the fallow–wheat system resulted in higher short-run net returns, the total biomass production and crop residue return to soil is much greater in camelina–wheat than fallow–wheat rotation, which is likely to improve soil quality and productivity in the long run. [ABSTRACT FROM AUTHOR]

Abstract: Biomass from land enrolled in the Conservation Reserve Program (CRP) is being considered as a biofuel feedstock source. A quick, accurate and nondestructive method to estimate biomass yield would be valuable for land managers to ensure sustainable production. The purpose of this study was to compare the ability of regression models to estimate biomass yields using data from satellite and ground based remote sensing platforms. Biomass yields and plant spectral responses were obtained at different phenological stages over two growing seasons (2011–2012) on an 8.1 ha CRP pasture in central Montana. Regression models were constructed using the normalized difference vegetation index (NDVI) and various band combinations from a hand held Crop Circle sensor and from Landsat satellite images. All models showed reasonable accuracy in estimating biomass, with a difference of <276 kg ha−1 or 8% of measured values. None of the models showed statistically significant differences (p > 0.05) between actual and estimated biomass. Results suggest that the usefulness of the spectral regions is a function of phenological growth stage. Red, red edge, and the near-infrared bands are more responsive at boot and peak growth stages while bands in the short-wave infrared increased the accuracy for the dormant stage biomass estimations. Land managers may construct spectral models to more effectively manage biomass resources. [Copyright &y& Elsevier]

Preferential flow allows agricultural chemicals to rapidly move past crop root zone to subsoil, potentially contaminating groundwater. Deep shrinkage cracks in a shrink/swell soil may serve as preferential flow channels. Design and operation of an irrigation system is critical in shrink/swell soils in order to reduce or eliminate preferential flow while providing sufficient water for plant growth. The objective of this study was to compare microsprinkler irrigation (MI) and surface flood irrigation (FI) systems for their ability to reduce preferential flow and chemical leaching through a shrink/swell soil in a pear orchard. The MI system applied water at a rate of 2.8 mm h−1, and the FI followed the traditional orchard irrigation method. Bromide tracer was applied to the pear orchard. Soil cores and percolate samples from passive capillary samplers (PCAPS) installed at 1.2 m depth were collected to test for the presence of Br tracer in the soil and percolate. The MI system greatly decreased water and Br leaching from soil to the PCAPS in comparison to FI. The percolate in MI was nearly zero. Most of the loss of Br occurred in the first one or two FI events. MI systems, such as that used in this study should be considered as an alternative to FI in such shrink/swell soils to reduce macropore flow. [Copyright &y& Elsevier]

Camelina ( Camelina sativa ) is a promising biofuel feedstock to fill the fallow period in dryland wheat ( Triticum aestivum ) −fallow cropping system of the U.S Northern Great Plains (NGP). Responses of camelina to tillage system (conventional tillage [CT] and no-till [NT]), nitrogen (N) rate (0, 45, 90 kg ha −1 ), and nitrogen source (urea and an enhanced efficiency nitrogen fertilizer [EENF] containing urease and nitrification inhibitors) were evaluated in a 2-yr (2013–2014) field experiment in a dryland farming system of central Montana. Grain yield, biomass, oil content, and oil yield of camelina displayed significant first-order effects of tillage, N rate, and N source when averaged across each of the other factors, but interaction effects were not significant. Camelina tended to yield greater in CT than NT by about 26%. Application of EENF significantly increased grain yield when compared with U, which was more pronounced under CT. Dose response of camelina grain yield, biomass, and grain protein to N rate in the range of 0 to 90 kg ha −1 was linear, whereas N fertilization showed a detrimental effect on oil accumulation in seeds. Although oil content declined in response to N application, oil yield (kg ha −1 ), which is the most important criterionin seedoil derived biofeedstock, positively responded to N application. Our results clearly demonstrated the need for further research to optimize management strategies for successful camelina production under NT system. Our results also indicated the potential of EENF in enhancing the yield of camelina, especially under CT system. Irrespective of tillage system and source of N, application of 90 kg N ha −1 (minus soil mineral N) led to the highest yield of camelina in this environment, but yield gain in response to N application greater than 45 kg ha −1 was very small. [ABSTRACT FROM AUTHOR]

Despite the great potential of camelina ( Camelina sativa L. Crantz) as a promising biofuel feedstock, in-farm energy flow of the crop and its associated environmental impacts has not received sufficient attention from researchers. In order to assess net energy gain and to identify energy saving and environmental friendly production operations, a two year study was conducted at central Montana. We investigated the effects of tillage method (CT (conventional tillage) vs. NT (no-tillage)) and N (nitrogen) fertilizer rate (0, 45, 90 kg N ha −1 ) on energy balance and GHG (greenhouse gas emission) of dryland camelina production. Results indicated that energy input and GHG emission were 5 and 8% lower in NT than in CT. Application of 45 and 90 kg N ha −1 increased camelina energy input by 186 and 365%, while increased energy output by only 21 and 64%, respectively. There was no significant difference in net energy gain in response to N fertilization, but lower energy efficiency in response to higher N inputs. Averaged across tillage systems, the GHG emission was 32.0 kg C eq ha −1 with 0 N applied, and the GHG emission increased by 206 and 389% when 45 and 90 kg N ha −1 was applied. Overall, N fertilizer had the biggest share in total energy input. Averaged over all experimental treatments, 14,945 MJ ha −1 net energy was obtained from camelina crop in this study which shows the potential of this crop as a bioenergy feedstock. Our result showed that implementation of NT is strongly recommendable for camelina production in this region. Moreover, improvement of N use efficiency has the highest priority to improve energy performance and reduce GHG emissions in camelina production. [ABSTRACT FROM AUTHOR]

Organic matter (OM) oxidized by slightly alkaline KMnO 4 , termed permanganate-oxidizable carbon (POXC), has recently emerged as a standardized indicator of active, labile carbon within soil quality frameworks. Yet, qualitative information on POXC, particularly in semiarid drylands, is very scarce. The aim of this study was to characterize POXC within three long-term field experiments in Montana, USA: (i) across a wide range of edaphic (e.g., % clay) and management conditions (e.g., cropping intensity) ( n  = 148); and (ii) to identify the molecular composition of soil OM before and after KMnO 4 treatment using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The content of POXC was significantly greater under perennial (382–685 mg/kg) or annual cropping (404–607 mg/kg) than fallow-wheat (359–543 mg/kg) systems. Soil OM changes, however, were equally or better expressed when considering soil organic carbon (SOC) concentration. The occurrence of POXC paralleled SOC ( R  = 0.87; P  < 0.001) and total nitrogen (TN) ( R  = 0.82; P  < 0.001) concentrations, regardless of soil textural differences. The ESI FT-ICR MS analyses of aqueous soil extracts indicated that the KMnO 4 reaction oxidized dissolved OM of diverse molecular character. OM molecular composition after KMnO 4 treatment was enriched by strongly reduced chemical constituents (O/C < 0.4) at greater condensed aromaticity (AI > 0.67) and hydrogen saturation (aliphatic composition; H/C > 1.5) across all heterogeneous groups (C c H h N n O o S s ). Although POXC is a rapid assay widely used for characterizing soil OM dynamics, it may not provide a clear advantage over SOC concentration in semiarid drylands. The view of POXC as a merely labile, simple biodegradable OM fraction needs to be reconsidered. [ABSTRACT FROM AUTHOR]

Reduction of ammonia (NH 3 ) emission in agricultural systems is highly important from agronomic, ecologic, and economic standpoints. We studied NH 3 volatilization from surface applied urea and SuperU ® (urea containing urease and nitrification inhibitors) and its interaction with tillage system (conventional tillage and no-tillage) in a dryland arable soil. Agronomic efficiency of the fertilizers was also assessed by measuring yield, agronomic N-efficiency, and apparent N-use of camelina ( Camelina sativa L.). Results indicated significant variation between the field and laboratory experiments. Due to wet spell around the time of fertilization, cumulative volatilization was significantly lower in the field study. NH 3 emission associated with SuperU in the field study was about 45% lower than regular urea, which was attributed to a) activity of urease inhibitor delayed SuperU hydrolysis for about five days and b) a rainfall occurred four days after fertilization that likely carried more fertilizer into the soil from SuperU than urea. In the incubation study, NH 3 loss was notable and superiority of SuperU was not seen. The results suggest that just replacing urea with SuperU would not result in mitigation of NH 3 emission, but it provides a greater chance for N to enter the soil by one way or another (rainfall in our study). Our results did not show any appreciable interaction between N fertilizers and tillage systems. Application of SuperU in the first year of the study resulted in a significantly higher camelina yield and agronomic N-efficiency, but in the second year, due to unfavorable environmental condition, camelina did not grow well thus did not respond positively to N fertilization. The superiority of SuperU over urea in terms of NH 3 volatilization and agronomic efficiency may be achieved if farmers apply the fertilizer timely in accordance with weather conditions. [ABSTRACT FROM AUTHOR]

The Northern Great Plains of the United States and Canada have seen an increase in pulse crops like pea, lentil, and chickpea acreage in dryland and irrigated systems. Rotating pulse crops into cereal crop production systems could reduce the demand for nitrogen fertilizer due to the symbiotic relationship with nitrogen fixing bacteria called diazotrophs. Legume-diazotroph relationships are well studied, but little is known about the free-living bacteria of the bulk soil in the legume-cereal rotation systems. Here we determine the community structure of the overall (16S) and diazotroph (nifH) soil microbiome in pulse-cereal rotations across the state of Montana. Many variables influenced the microbial community structure, but and among them, irrigation caused a significant shift in the composition of the communities and co-occurrence network topology. Interestingly, the diazotrophic communities in dryland soil are more robust and contain more generalist compared to irrigated soils. Co-occurrence networks support the identification of different diazotrophic keystone taxa such as Firmicutes in irrigated and Proteobacteria in dryland soils. Linking farm management practices and crop productivity with microbial community structure dynamics is an initial step in establishing a knowledge base for farmers to exploit the soil microbiota to maintain healthy soil for crop production. • Geographic location, farm management, and edaphic factors affect the free-living microbiome. • Irrigation disrupts general (16S) and diazotroph (nifH) bacteria communities differently. • Co-occurrence shifts in diazotrophic communities are due to irrigation. • Nitrogen-fixing keystone species are affected by irrigation in bulk soil [ABSTRACT FROM AUTHOR]