Biomass Production of ‘Alamo’ Switchgrass in Response to Nitrogen, Phosphorus, and Row Spacing

Abstract

yr Ϫ1 ; Wolf and Fiske, 1995; Brejda, 2000). The compromise between yield and quality does not apply to bio-Management practices for biomass production of bioenergy grasses mass production for bioenergy feedstock because the may differ from management for forage. Our objective was to determine the yield and stand responses of 'Alamo' switchgrass (Panicum goal generally is to maximize production of lignocelluvirgatum L.) to N and P fertilization as affected by row spacing. A lose (Sanderson et al., 1999a). Thus, management praccombination of five rates each of N and P were applied to plots during tices that maximize biomass production may differ from 1992 to 1998 at Stephenville, TX and 1993 to 1995 at Beeville, TX.that for herbage production. Annual yield of several Three row-spacing treatments were applied as subplots. Biomass proswitchgrass cultivars in Texas fertilized with 134 kg N duction was determined each year with a single harvest in late summer. ha Ϫ1 ranged from 8 to 20 Mg ha Ϫ1 , depending mainly Tiller density and tiller mass were measured during 1993 to 1996 at on seasonal rainfall variations (Sanderson et al., 1999b). Stephenville. Biomass production was not influenced by the additionAlamo switchgrass was the most adapted cultivar for of P. Biomass production response to N at Beeville was greater in the south-central USA. narrow rows than wide rows during the establishment year only. Bio-Phosphorus fertilizer recommendations for switchmass production responses to N were quadratic in 5 of 7 yr at Stephenville and linear at Beeville. A maximum yield of 22.5 Mg ha Ϫ1 occurred grass depend on soil pH, P supplying power of the soil, during 1995 at Stephenville at 168 kg N ha Ϫ1 . Lodging occurred atand soil test P (Brejda, 2000). In the central Great Plains, both locations but only at the 224 kg N ha Ϫ1 rate. Tiller density and P recommendations for switchgrass ranged from 0 to mass increased as row width increased. Tiller mass also increased 35 kg ha Ϫ1 , depending on soil test P (Brejda, 2000). In Oak Ridge Natl. Lab. managed by Martin Marietta Energy Systems.

Biomass Yield and Nutrient Responses of Switchgrass to Phosphorus Application

“…ischaemum), and native ranges that included switchgrass in Oklahoma [29]. Unlike a previous study where no yield response to 39 kg Pha −1 was observed for switchgrass in Texas [5], the increased yield obtained with 45 kg Pha −1 in this study may have resulted from better stand development, increased soil plant available P, and better P scavenging by the roots. The low P response may be due to inherent ability of switchgrass to efficiently use P or extract fixed P in the soil.…”

“…However, there is limited information on its fertilizer requirement including phosphorus (P) rates needed to optimize biomass yields. Previous research in this region has generally shown that switchgrass biomass yields respond to nitrogen (N) fertilizer rates of up to 168 kg ha −1 , depending on ecotype and location [4][5][6]. Phosphorus, a plant macronutrient reported to limit plant growth and productivity in 40% of the world's arable soil [7], is a constituent of macromolecular structures like nucleic acids and is critical for synthesis of energy transfer organic compounds such as adenosine triphosphate in plants [8].…”

Managing and enhancing switchgrass as a bioenergy feedstock

“…Switchgrass did not respond to applied P in Texas 25 or in low P soils in Iowa. 28 However, research in Nebraska suggested switchgrass may respond to applied P if P availability in the soil is low.…”

“…However, Stephenville and Beeville, respectively. 25 Biomass production declined over years without applied N, and was sustainable only with the application of at least 168 kg N ha −1 yr −1 . In Alabama, Ma et al 26 reported switchgrass yields increased as N rate increased up to 224 kg N ha −1 .…”

Economic Evaluation of Switchgrass Feedstock Production Systems Tested in Potassium-Deficient Soils

“…Extensive soil testing has revealed that a substantial percentage of acres in the southern Great Plains are deficient in potassium (K), primarily those in the eastern areas that are comprised of sandy soils and receive greater than 889 mm of rainfall each year [2]. At present, most switchgrass fertilizer management studies have mainly focused on the benefits and costs associated with nitrogen (N) fertilizer as the primary limiting nutrient [3][4][5] and a few studies have focused on phosphorus (P) fertilizer [1,6,7]. However, little information is available regarding the costs and benefits associated with N and K fertilization on switchgrass produced in K-deficient soils.…”