Biomass Yield of Switchgrass Cultivars under High- versus Low-Input Conditions

Switchgrass (Panicum virgatum L.) is undergoing development as a biomass crop to support conversion of cellulosic biomass to energy. To avoid the competition of biomass with food or feed crops, most commercialization proposals suggest that switchgrass should be grown exclusively on marginal lands that are not fit for food or feed production. The objective of this study was to investigate the potential for cultivar x environment interactions that would affect the methods and approaches for breeding and evaluating switchgrass cultivars, including both upland and lowland types, for high-input versus low-input types of environments. Biomass yield was measured on 14 cultivars that were present in 28 replicated field experiments representing seven regions, ranging from 75 to 100° W and spanning USDA Hardiness Zones 4 through 7. Region was the most important environmental factor interacting with cultivars, supporting the idea that the north-central and northeastern United States should have independent switchgrass breeding programs. Cultivars interacted with soil phosphorus concentration in New Jersey and with depth of the A and B horizons in New York and showed mild interactions with rate of nitrogen fertilizer at several locations. Cultivar rank correlation coefficients between the two rates of nitrogen fertilization (100 vs. 0 kg N ha−1) ranged from 0.23 to 0.88, suggesting a possible benefit to breeding and selection without applied nitrogen fertilizer

THE SOIL/PLANT/PATHOGEN ASPECTS OF POTATO LATE BLIGHT

PhD DissertationOospores of Phytophthora infestans produced in vitro and in planta, were exposed to a variety of environments and their survival was assessed. Viability of oospores as measured by plasmolysis declined slightly over a period of 18 months whether they were stored in water at 4?C, in soil at 18?C, or in soil under natural field conditions. In comparison, viability as measured by germination was lower overall, but appeared to increase after storage in soil. Oospores produced in planta buried in the field were capable of infecting both tomato and potato leaflets when recovered after eighteen months, including two winters. Soil samples collected from the central highlands of Mexico (center of diversity for Phytophthora infestans) were evaluated for suppressive activity to P. infestans. A New York soil was used for comparative analysis. Even though both mating types are known to cohabit these regions of Mexico no evidence of oospores was found in the soil samples. No significant differences were observed between the Mexican and New York soils in terms of their influence on survival and infectivity of P. infestans. Bacterial diversity in the different soil types was investigated using terminal restriction fragment length polymorphism analysis (T-RFLPs). Foliar and tuber resistance to Phytophthora infestans were evaluated in a mapping population (n = 94) developed between two Solanum tuberosum breeding lines, NY121 x NY115. Foliar disease severity of the progeny clones was measured by the area under the disease progress curve (AUDPC) in field tests in 2004 and 2005. Correlation analysis of AUDPC values with amplified fragment length polymorphism (AFLP) molecular markers revealed that 56 %, 53 %, and 52 % of the quantitative phenotypic variance for resistance were associated with markers PCTMATC 184, PATMATA 171, and PATMACT 236, respectively, located on a chromosome V homolog derived from NY121 (p < 0.00001). The genetic component of tuber blight variance was much smaller than the foliar blight component, but still these three markers were correlated (p < 0.01 ? 0.10) with tuber blight resistance and explained 3-8 % of the variance

Development of Superabsorbent Polymer (SAP) Seed Coating Technology to Enhance Germination and Stand Establishment in Red Clover Cover Crop

Drought conditions after sowing threaten the seedling establishment of all seeds, including cover crops. Cover crops are commonly broadcast and, thus, are often susceptible to drought stress after sowing. Our hypothesis was that seed coating with superabsorbent polymers (SAPs) would enhance germination in the lab and stand establishment in the field by increasing water availability to single seeds. Red clover (Trifolium pratense L.) seeds were coated with the following selected SAP formulations at 2% of their seed weight: cross-linked potassium polyacrylate (PAL), cross-linked polyacrylamide-based polymer (PAM), PAM with graphite (PAM+G), and Starch-g-2-Propenoic acid (potassium salt) (STR). The water absorbency of each SAP formulation was >200 g water/g of polymer; STR had the greatest absorbency, at 352 g water/g of polymer. A seed coating method was developed, resulting in the uniform application of SAP from seed to seed. All SAP coating treatments increased germination compared to the 0% SAP coating in controlled environment studies in the lab. Three field trials were conducted for each seed coating treatment, providing a range of climatic soil conditions. Within each field trial, the STR with the greatest water absorbency had a higher stand for treatments sown by broadcasting followed by raking to incorporate seeds. The first two trials were conducted under more stressful conditions. PAM+G performed best in the first two trials by broadcasting seeds with no raking. Collectively, the selected SAP seed coating improved field stands compared to the non-treated controls

Tomato Seed Coat Permeability: Optimal Seed Treatment Chemical Properties for Targeting the Embryo with Implications for Internal Seed-Borne Pathogen Control

Seed treatments are frequently applied for the management of early-season pests, including seed-borne pathogens. However, to be effective against internal pathogens, the active ingredient must be able to penetrate the seed coat. Tomato seeds were the focus of this study, and the objectives were to (1) evaluate three coumarin fluorescent tracers in terms of uptake and (2) quantify seed coat permeability in relation to lipophilicity to better elucidate chemical movement in seed tissue. Uptake in seeds treated with coumarin 1, 120, and 151 was assessed by fluorescence microscopy. For quantitative studies, a series of 11 n-alkyl piperonyl amides with log Kow in the range of 0.02–5.66 were applied, and two portions, namely, the embryo, and the endosperm + seed coat, were analyzed by high-performance liquid chromatography (HPLC). Coumarin 120 with the lowest log Kow of 1.3 displayed greater seed uptake than coumarin 1 with a log Kow of 2.9. In contrast, the optimal log Kow for embryo uptake ranged from 2.9 to 3.3 derived from the amide series. Therefore, heterogeneous coumarin tracers were not suitable to determine optimal log Kow for uptake. Three tomato varieties were investigated with the amide series, and the maximum percent recovered in the embryonic tissue ranged from only 1.2% to 5%. These data suggest that the application of active ingredients as seed treatments could result in suboptimal concentrations in the embryo being efficacious

A Seed Coating Delivery System for Bio-Based Biostimulants to Enhance Plant Growth

A novel delivery method for the application of bio-based biostimulants as seed coatings was developed using different sources of liquid and powder forms of vermicompost and soy flour. Micronized vermicompost (MVC) and soy flour (SF) were mixed in different combinations as dry seed coating blends and applied using rotary pan seed coating equipment. The physical properties of coated seeds were measured, and as binder concentration increased, coating strength increased. The rates and percentages of germination of the newly developed coating formulations of SF+MVC did not decrease the germination parameters and were not significantly different than the control. However, the SF, SF with concentrated vermicompost extract, and SF + MVC from dairy manure increased the seedling vigor index by 24, 30, and 39 percent, respectively, compared to the control. Plant biometric parameters and nitrogen uptake per plant were also significantly higher for SF and SF+MVC coated seeds than the control, in a greenhouse environment. This is the first seed coating study to show an enhancement of plant growth with vermicompost, and vermicompost in combination with a plant-based protein that serves as a dry seed coating binder and biostimulant, respectively. Seed coatings developed in this study can serve as a model for development of the delivery systems of seeds for the application of bio-based biostimulants to enhance early plant growth

Evaluation of Industrial Hemp Seed Treatments for Management of Damping-Off for Enhanced Stand Establishment

The purpose of this research was to collect efficacy data on biological, biochemical, and chemical fungicide seed treatments on hemp (Cannabis sativa L.) to mitigate damping-off and enhance field stand establishment. Seed treatments were evaluated in fields in New York (NY), North Dakota (ND), and Virginia (VA) and at two planting dates in each state in 2020. A single seed lot of a dual-purpose (fiber + grain) cultivar (‘Anka’) was treated using a laboratory-scale rotary pan coater. Five biological, two biochemical, and four chemical seed treatments were tested. A laboratory germination test revealed that seed treatments did not exhibit phytotoxicity when compared to the non-treated control. A laboratory bioassay with naturally infested soil was used to assess the preliminary activity of seed treatments for protection against damping-off. The biochemical seed treatment Ultim® (active ingredient; organic copper) performed as well as the chemical treatments Apron XL® + Maxim® 4FS and Mertect® 340F in preventing damping-off whereas the biological treatments did not differ from the non-treated control in terms of disease incidence. In all field tests, biological seed treatments did not improve plant stands compared to the non-treated control. Biochemical seed treatments Prudent 44® with Nutrol® (active ingredient; phosphite) and Ultim®, along with chemical seed treatments, had acceptable efficacy and improved stand establishment compared to the non-treated control across field locations. Based on efficacy results from laboratory and field trials, the copper seed treatment has potential for both conventional and organic hemp production

Switchgrass nitrogen response and estimated production costs on diverse sites

Switchgrass (Panicum virgatum L.) has been the principal perennial herbaceous crop investigated for bioenergy production in North America given its high production potential, relatively low input requirements, and potential suitability for use on marginal lands. Few large trials have determined switchgrass yields at field scale on marginal lands, including analysis of production costs. Thus, a field-scale study was conducted to develop realistic yield and cost estimates for diverse regions of the USA. Objectives included measuring switchgrass response to fertility treatments (0, 56, and 112 kg N ha-1) and generating corresponding estimates of production costs for sites with diverse soil and climatic conditions. Trials occurred in Iowa, New York, Oklahoma, South Dakota, and Virginia, USA. Cultivars and management practices were site specific, and field-scale equipment was used for all management practices. Input costs were estimated using final harvest-year (2015) prices, and equipment operation costs were estimated with the MachData model ($2015). Switchgrass yields generally were below those reported elsewhere, averaging 6.3 Mg ha-1 across sites and treatments. Establishment stand percent ranged from 28$70 and $63 Mg-1, respectively. For some sites, typically promoted N application rates may be economically unjustified; it remains unknown whether a bioenergy industry can support the breakeven prices estimated for sites where N inputs had positive effects on switchgrass yield

Switchgrass nitrogen response and estimated production costs on diverse sites

Switchgrass (Panicum virgatum L.) has been the principal perennial herbaceous crop investigated for bioenergy production in North America given its high production potential, relatively low input requirements, and potential suitability for use on marginal lands. Few large trials have determined switchgrass yields at field scale on marginal lands, including analysis of production costs. Thus, a field-scale study was conducted to develop realistic yield and cost estimates for diverse regions of the USA. Objectives included measuring switchgrass response to fertility treatments (0, 56, and 112 kg N ha−1) and generating corresponding estimates of production costs for sites with diverse soil and climatic conditions. Trials occurred in Iowa, New York, Oklahoma, South Dakota, and Virginia, USA. Cultivars and management practices were site specific, and field-scale equipment was used for all management practices. Input costs were estimated using final harvest-year (2015) prices, and equipment operation costs were estimated with the MachData model ($2015). Switchgrass yields generally were below those reported elsewhere, averaging 6.3 Mg ha−1 across sites and treatments. Establishment stand percent ranged from 28$70 and $63 Mg−1, respectively. For some sites, typically promoted N application rates may be economically unjustified; it remains unknown whether a bioenergy industry can support the breakeven prices estimated for sites where N inputs had positive effects on switchgrass yield.This article is published as Fike, J. H., Pease, J. W., Owens, V. N., Farris, R. L., Hansen, J. L., Heaton, E. A., Hong, C. O., Mayton, H. S., Mitchell, R. B. and Viands, D. R. (2017), Switchgrass nitrogen response and estimated production costs on diverse sites. GCB Bioenergy, 9: 1526–1542. doi:10.1111/gcbb.12444. </p

Untapped Potential : Opportunities and Challenges for Sustainable Bioenergy Production from Marginal Lands in the Northeast USA

Over two million hectares of marginal land in the Northeast USA no longer used for agriculture may be suitable and available for production of second-generation cellulosic bioenergy crops, offering the potential for increased regional bioenergy production without competing with food production on prime farmland. Current yields of perennial bioenergy grasses and short-rotation woody crops range from 2.3 to 17.4 and 4.5 to 15.5 Mg/ha, respectively, and there is great potential for increased yields. Regional advantages for bioenergy development include abundant water resources, close proximity between production and markets, and compatibility of bioenergy cropping systems with existing agriculture. As New York and New England (a subset of the Northeast region) account for ~85 % of the nation’s heating oil consumption, production of bioheat, biopower, and combined heat and power could substantially reduce the region’s dependence on imported petroleum. While numerous grassroots efforts are underway in the region across supply chains, bioenergy development faces several challenges and unknowns in terms of environmental impact, production, yields, socioeconomics, and policy. We explore the opportunities for second-generation bioenergy production on the unused marginal lands of the Northeast USA and discuss the challenges to be addressed to promote sustainable bioenergy production on the region’s underutilized marginal land base

Key environmental and production factors for understanding variation in switchgrass chemical attributes

Switchgrass (Panicum virgatum L.) is a promising feedstock for bioenergy and bioproducts; however, its inherent variability in chemical attributes creates challenges for uniform conversion efficiencies and product quality. It is necessary to understand the range of variation and factors (i.e., field management, environmental) influencing chemical attributes for process improvement and risk assessment. The objectives of this study were to (1) examine the impact of nitrogen fertilizer application rate, year, and location on switchgrass chemical attributes, (2) examine the relationships among chemical attributes, weather and soil data, and (3) develop models to predict chemical attributes using environmental factors. Switchgrass samples from a field study spanning four locations including upland cultivars, one location including a lowland cultivar, and between three and six harvest years were assessed for glucan, xylan, lignin, volatiles, carbon, nitrogen, and ash concentrations. Using variance estimation, location/cultivar, nitrogen application rate, and year explained 65%–96% of the variation for switchgrass chemical attributes. Location/cultivar × year interaction was a significant factor for all chemical attributes indicating environmental-based influences. Nitrogen rate was less influential. Production variables and environmental conditions occurring during the switchgrass field trials were used to successfully predict chemical attributes using linear regression models. Upland switchgrass results highlight the complexity in plant responses to growing conditions because all production and environmental variables had strong relationships with one or more chemical attributes. Lowland switchgrass was limited to observations of year-to-year environmental variability and nitrogen application rate. All explanatory variable categories were important for lowland switchgrass models but stand age and precipitation relationships were particularly strong. The relationships found in this study can be used to understand spatial and temporal variation in switchgrass chemical attributes. The ability to predict chemical attributes critical for conversion processes in a geospatial/temporal manner would provide state-of-the-art knowledge for risk assessment in the bioenergy and bioproducts industry.This article is published as Hoover, Amber N., Rachel Emerson, Marnie Cortez, Vance Owens, Ed Wolfrum, Courtney Payne, John Fike et al. "Key environmental and production factors for understanding variation in switchgrass chemical attributes." GCB Bioenergy (2022). doi:10.1111/gcbb.12942. Posted with permission. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited