Yield and Stand Persistence of Switchgrass as Affected by Cutting Height and Variety

Ashworth, Amanda J.; Keyser, Patrick D.; Holcomb, Elizabeth D.; Harper, Craig A.

doi:10.1094/fg-2013-0043-rs

Cited by 10 publications

(8 citation statements)

References 15 publications

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“…Therefore, bermudagrass tended to encroach and outcompete switchgrass under repeated forage harvests and under greater N fertility, based on terminal community composition (Figure 2). Similar declines have been observed when multiple pre‐ or postanthesis harvests are conducted per annum due to continued growing‐point removal (at ∼15 cm) during the growing season (Ashworth, Keyser, Doxon, & Harper, 2014; Thomason et al., 2005). This suggests that, although multiple growing season harvests may produce more forage in early stand years, a decline in switchgrass vigor after 3–4 yr of intensive harvest management may occur, as observed by Thomason et al.…”

Section: Resultssupporting

confidence: 54%

Switchgrass nitrogen fertility response and nutrient cycling in a hay system

Ashworth

Moore

King³

et al. 2020

Agronomy Journal

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Nitrogen (N) requirements for switchgrass (Panicum virgatum L.) forage production in the Mid-south are largely unknown. This study determined switchgrass forage yield, quality, N removal, and soil fertility response in a two-forage harvest (pre-anthesis) system after split applications of 0, 84, 168, 252, and 336 kg N ha -1 yr -1 from 2014 to 2016. Controls were represented by no fertilizer and a 0 N rate with supplemental P, K, Mg, and S. For all experimental years, yield did not benefit from supplemental P, K, Mg, and S, suggesting N was the limiting nutrient. Yield also did not differ between the 252 and the 336 kg N ha -1 yr -1 rates (9.2 and 9.4 Mg ha -1 , respectively), indicating no further growth beyond the 252 kg N ha -1 threshold in a two-cut forage system. At greater N fertility rates (336 kg N ha -1 ), the majority of the soil nutrient concentrations were reduced compared with the 252 kg N ha -1 rate, owing to greater nutrient removal in harvested plant tissue. Tissue N removal was greatest for the highest N application, albeit not different from the 252 kg N ha -1 rate; N use efficiency had an inverse relationship with N removal, peaking during the lowest N application (84 kg N ha -1 ). Forage quality varied, but, in general, digestibility improved under greater N fertility. Quantifying trends in forage yield and quality based on N fertility are useful for predicting break-even prices per fertilizer response.Abbreviations: ADF, acid detergent fiber; CP, crude protein; NDF, neutral detergent fiber; NUE, nutrient use efficiency; TDN, total digestible nutrients.This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.

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Section: Resultssupporting

confidence: 54%

Switchgrass nitrogen fertility response and nutrient cycling in a hay system

Ashworth

Moore

King³

et al. 2020

Agronomy Journal

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“…crop economIcs, proDuctIon, AnD mAnAgement 'Kanlow' but not for the upland-type 'Cave-in-Rock' (Ashworth et al, 2014). To date, there is limited information on defoliation management effects for cv.…”

Section: Core Ideasmentioning

confidence: 99%

Defoliation Management Affects Productivity, Leaf/Stem Ratio, and Tiller Counts of ‘Performer’ Switchgrass

2018

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Core Ideas Defoliation management resulted in a wide range of plant responses that varied by year, with deleterious responses more evident in the second year. Greater leaf/stem ratios occurred with more frequent defoliation treatments. Frequent defoliations such as every 3 wk should maintain a stubble height of at least 40 cm, defoliation frequencies ≥6 wk to 20‐cm stubble height, and ≥9 wk to 10 cm stubble height are warranted to ensure stand persistence. ‘Performer’ switchgrass (Panicum virgatum L.) was released in 2006 by the USDA‐NCSU forage program because of its greater digestibility compared to standard cultivars grown in the southeastern United States. Forages with greater digestibility have potential to positively impact animal responses, however, defoliation management can influence its productivity and persistence. The objectives were to determine the effect of the factorial combination of four defoliation heights (DH) (clipped to 10, 20, 30, and 40‐cm) and four defoliation frequencies (DF) (clipped every 3, 6, 9, and 12 wk) on productivity, leaf/stem ratio, and tiller counts. The experiment was conducted in 2016 and 2017 at the Central Crops Research Station, Clayton, NC. The 16 treatments were allocated in a complete randomized block design replicated four times. In 2016, total dry matter (DM) yield ranged from 4.2 to 13.1 Mg ha−1 being greatest for the 9‐ and 12‐wk DF at 10‐ and 20‐cm DH and lowest for all DH at 3‐wk defoliation frequency. In 2017, the DM yield range was wider ranging from 0.5 to 14.0 Mg ha−1 with lower tiller counts for the 10‐ and 20‐cm DH, 3‐wk DF treatments. Leaf/stem ratio was greater for the more frequently defoliated treatments in both years. ‘Performer’ switchgrass is a productive forage and on the basis of total DM harvested, leaf/stem ratio, and tiller counts, frequent defoliations such as every 3 wk to 40‐cm stubble height, ≥6 wk to 20‐cm stubble height, and ≥ 9 wk to 10 cm stubble height, are warranted to ensure stand persistence.

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“…Ashworth, Keyser, Holcomb, and Harper () reported that the effects of switchgrass defoliation management varies by cultivar. Clipping to ≤20‐cm stubble height reduced stands of lowland switchgrass ‘Alamo’ and ‘Kanlow’ but not for the upland‐type ‘Cave‐in‐Rock’ (Ashworth et al., ). Bekewe, Castillo, and Rivera (, ) reported that clipping to 10‐cm stubble height resulted in lower dry matter yield and greater weed infestation of ‘Performer’ switchgrass when defoliation occurred every 3 wk, but not when compared to defoliating every 9 or 12 wk.…”

Section: Introductionmentioning

confidence: 99%

Defoliation management effects on nutritive value of ‘performer’ switchgrass

et al. 2020

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Forage species with greater nutritive value have the potential to positively affect animal responses. 'Performer' switchgrass (Panicum virgatum L.) was released because of greater digestibility and lower lignin concentrations as compared to 'Alamo' and 'Cave-in-Rock.' However, the relationship between nutritive value, canopy characteristics, and dry matter yield for this species has not yet been established. The goal of this study was to determine in vitro true digestibility (IVTD), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) as a function of a wide range of defoliation management strategies to aim optimize production of nutritious forage. Treatments were the factorial combination (4 × 4) of defoliation height (DH; clipped to 10, 20, 30, and 40 cm) and defoliation frequency (DF; clipped every 3, 6, 9, and 12 wk). The range of digestibility values was greater due to DF (from 590-779 g kg −1 when averaged across DH treatments) than DH treatments (from 675-692 g kg −1 when averaged across DF treatments). In general, frequent defoliation resulted in greater IVTD and CP but lower yields; however, there were interaction effects of DF × DH for all response variables. With the exception of NDF, all response variables had strong correlations with dry matter yield, canopy height, and leaf/stem ratio. Although there are tradeoffs when managing for productivity and nutritive value, there is a wide range of defoliation management options for 'Performer' switchgrass that provide flexibility in terms of harvesting schedules to optimize productivity and persistence of nutritious forage.

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Yield and Stand Persistence of Switchgrass as Affected by Cutting Height and Variety

Cited by 10 publications

References 15 publications

Switchgrass nitrogen fertility response and nutrient cycling in a hay system

Switchgrass nitrogen fertility response and nutrient cycling in a hay system

Defoliation Management Affects Productivity, Leaf/Stem Ratio, and Tiller Counts of ‘Performer’ Switchgrass

Defoliation management effects on nutritive value of ‘performer’ switchgrass

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