Nitrogen removal in switchgrass biomass under two harvest systems

Reynolds, J. H.; Walker, Cynthia L.; Kirchner, Miranda

doi:10.1016/s0961-9534(00)00042-8

Cited by 100 publications

(74 citation statements)

References 11 publications

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“…Because cultivars differ in phenology (Berdahl et al 2005, Casler 2005, Parrish and Fike 2005, and locations differ in day length and growing season, it is not surprising that the period of sensitivity might vary among studies. Management factors play a role as well; low rainfall in August-September reduced yields in a two-cut, but not in a one-cut system (Reynolds et al 2000). Soil texture and depth, topography (e.g., distance from a stream), supplemental irrigation, different cultivar requirements, or excess rainfall close to harvest could all confound an overall relationship between yield and annual or "growing season" precipitation (Cassida et al 2005b).…”

Section: Precipitationmentioning

confidence: 99%

Exploring Potential U.S. Switchgrass Production for Lignocellulosic Ethanol

Gunderson¹,

Davis²,

Jager³

et al. 2008

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Section: Precipitationmentioning

confidence: 99%

Exploring Potential U.S. Switchgrass Production for Lignocellulosic Ethanol

Gunderson¹,

Davis²,

Jager³

et al. 2008

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“…Nonetheless, substantial amounts of soil nutrients are removed with the harvested shoot biomass. For example, total N removed with biomass varied from 31 to 63 kg N ha −1 year −1 in a one-cut fall harvest after senescence, compared to 90 to 144 kg ha −1 year −1 for a twocut system with the first harvest prior to senescence, over 5 years of measurements [6]. Such nutrient withdrawal rates inevitably deplete soil N and necessitate the addition of fertilizer N to maintain switchgrass productivity.…”

Section: Introductionmentioning

confidence: 99%

PvNAC1 and PvNAC2 Are Associated with Leaf Senescence and Nitrogen Use Efficiency in Switchgrass

et al. 2014

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Two full-length cDNAs encoding NAM, ATAF, and CUC (NAC)-family transcription factors (TFs) were isolated from two different cultivars of Panicum virgatum L. (switchgrass) and named PvNAC1 and PvNAC2. Phylogenetic analysis of PvNAC1 and PvNAC2 grouped them with NAC proteins involved in senescence in annual plant species. Transcript profiling revealed that both PvNAC1 and PvNAC2 are induced during leaf senescence. Expression of a PvNAC1-green fluorescent protein (GFP) fusion in plant cells revealed a nuclear location of the protein, consistent with a role in transcriptional regulation. Expression of PvNAC1 in an Arabidopsis nap stay-green mutant suppressed its senescence defect. Expression of PvNAC1 in wild-type Arabidopsis triggered early leaf senescence and remobilization. Transcriptome analysis implicated leaf protein degradation and nitrogen recycling enzymes in NAC-dependent seed protein increase in Arabidopsis. Overexpression of pvNAC2 in switchgrass resulted in increased aboveground biomass associated with increased transcript levels of key nitrogen metabolism genes in leaves and nitrate and ammonium transporter genes in roots. The results indicate that NAC TFs play conserved roles in leaf senescence in the plant kingdom not only in annual monocots and dicots but also in perennial plants such as switchgrass. PvNAC1 and PvNAC2 hold promise for improving nutrient use efficiency in switchgrass through genetic manipulation.

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“…Fertilizer N is the main energy input and source of greenhouse gases emissions during switchgrass cultivation for biofuel purposes (Adler et al, 2007;Schmer et al, 2008). The N fertilizer requirement of switchgrass is dependent, in part, on the amount of crop N removal at harvest, which is related to the number and timing of annual harvest operations (Reynolds et al, 2000;Heaton et al, 2009). In addition, harvest practices also affect biomass biofuel quality (Adler et al, 2006), such as biomass moisture content and mineral concentration.…”

Section: Introductionmentioning

confidence: 99%

Productivity, ¹⁵N dynamics and water use efficiency in low‐ and high‐input switchgrass systems

et al. 2014

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Sustainable and environmentally benign switchgrass production systems need to be developed for switchgrass to become a large-scale dedicated energy crop. An experiment was conducted in California from 2009 to 2011 to determine the sustainability of low-and high-input irrigated switchgrass systems as a function of yield, irrigation requirement, crop N removal, N translocation from aboveground (AG) to belowground (BG) biomass during senescence, and fertilizer 15 N recovery (FNR) in the AG and BG biomass (0-300 cm), and soil (0-300 cm). The low-input system consisted of a single-harvest (mid-fall) irrigated until flowering (early summer), while the high-input system consisted of a two-harvest system (early summer and mid-fall) irrigated throughout the growing season. Three N fertilization rates (0, 100, and 200 kg N ha À1 yr À1) were applied as subtreatments in a single application in the spring of each year. A single pulse of 15 N enriched fertilizer was applied in the first year of the study to micro-plots within the 100 kg N ha À1 subplots. Average yields across years under optimal N rates (100 and 200 kg ha À1 yr À1 for low-and high-input systems, respectively) were 20.7 and 24.8 Mg ha À1 .However, the low input (372 ha mm) required 47% less irrigation than the high-input system (705 ha mm) and achieved higher irrigation use efficiency. In addition, the low-input system had 46% lower crop N removal, 53% higher N stored in BG biomass, and a positive N balance, presumably due to 49% of 15 N translocation from AG to BG biomass during senescence. Furthermore, at the end of 3 years, the low-input system had lower fertilizer 15 N removed by harvest (26%) and higher FNR remaining in the system in BG biomass plus soil (31%) than the high-input system (45% and 21%, respectively). Based on these findings, low-input systems are more sustainable than high-input systems in irrigated Mediterranean climates.

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Nitrogen removal in switchgrass biomass under two harvest systems

Cited by 100 publications

References 11 publications

Exploring Potential U.S. Switchgrass Production for Lignocellulosic Ethanol

Exploring Potential U.S. Switchgrass Production for Lignocellulosic Ethanol

PvNAC1 and PvNAC2 Are Associated with Leaf Senescence and Nitrogen Use Efficiency in Switchgrass

Productivity, ¹⁵N dynamics and water use efficiency in low‐ and high‐input switchgrass systems

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Nitrogen removal in switchgrass biomass under two harvest systems

Cited by 100 publications

References 11 publications

Exploring Potential U.S. Switchgrass Production for Lignocellulosic Ethanol

Exploring Potential U.S. Switchgrass Production for Lignocellulosic Ethanol

PvNAC1 and PvNAC2 Are Associated with Leaf Senescence and Nitrogen Use Efficiency in Switchgrass

Productivity, 15N dynamics and water use efficiency in low‐ and high‐input switchgrass systems

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Productivity, ¹⁵N dynamics and water use efficiency in low‐ and high‐input switchgrass systems