Biomass Production and N Removal by Switchgrass under Irrigation

Biomass Production and N Removal by Switchgrass under Irrigation Hal Collins, USDA-ARS Vegetable and Forage Crops Unit 24106 N. Bunn Rd. Prosser WA 99350 Stephen Fransen 2, and Rick Boydston 1, 1 USDA-ARS Prosser, WA 2 Washington State University-IAREC, Prosser, WA Switchgrass Production Workshop, Prosser, WA, Dec 8, 2010

Projected U.S. Ethanol Production billion gallons 25 20 15 10 5 0 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Demand for all-e10 represents Scenario a 15 billion Baseline gallon market Other estimates suggest a maximum of 26 32 billion gals of ethanol production by 2016. (not all from corn grain)

Projected Utilization of U.S. Corn million bushels 7000 6000 5000 39 M ac - 400 From Tokgoz, et al., 2007. CARD, Iowa State Univ. 4000 3000 2000 23 M ac 14 M ac +1800 -- Additional 12 M acres - 500 1000 0 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 Feed Fuel HFCS Seed Food, Other Exports U.S. corn production was 13 billion bushels in 2007 and projected to increase to ~15 billion bushels by 2010. Yield 150 bu/ac

Corn Exports: Food Production Impacts of ethanol production on food production: Global Grain market reserves have fallen from 120 days in 2000 to 40 days in 2008. With continued diversion of corn acreage, reserves could fall to 20 day reserves by 2010. Reductions in U.S. exports will be made up by increased production and exports from South America. What impact will this have on U.S. corn exports when corn-based ethanol production declines?

Near-term:Where will the acres come from? 34 M acres of corn needed to support the 15 billion gal ethanol industry in 2010. (36%) To support the projected need for 12 million acres of corn in 2010.. 6 M acres - will come from a reduction in the supply of feed corn and export markets. Soybean acreage - currently 63 M acres Other crops (small grains other than wheat) CRP lands 37 million acres nation wide. - 7.2 M acres are considered less erodible and suitable for corn production. (source USDA, 2008).

Long-term:Where will the acres come from? Projected U.S. Ethanol Production - by 2016 will be ~30 billion gals - if from corn would need 68 M acres (72%) - would need alternative source for 15 billion gals

Long-term:Where will the acres come from? Projected U.S. Ethanol Production - by 2016 will be ~30 billion gals - if from corn would need 68 M acres (72%) - would need alternative source for 15 billion gals Ethanol: Cellulosic (crop residues, switchgrass) Crop residues (corn stover, small grain residues) - No new lands required - DOE estimated 428 M dry t of residues. (2006) - 34 billion gals of ethanol - 28% (120 M dry t) will be available for conversion - 8.4 billion gals of ethanol Dedicated crops - perennial crops (switchgrass, poplars, etc.)

Biomass for Cellulosic Ethanol Dedicated Crops Crop Residues Wheat, barley, grass seed Tall wheat grasses for CRP Switchgrass (15-20 T/A) Arundo donax (20-25 T/A) Corn stover

Acres to support a 20M gal ethanol facility. Precipitation Zone Arid Zone (<12 in yr -1 ) Low Zone (12-15 in. yr -1 ) Medium Zone (15-17 in. yr -1 ) High Zone (17-23 in yr -1 ) Residue Yield ton acre -1 Ethanol Yield gal ac -1 Acres to support a 20 M gal Facility 0.7 56 357,100 1.1 88 227,300 2.3 184 108,700 3.4 272 73,500 Irrigated Zone 5.0 400 50,000 Estimated ethanol yield from wheat straw is 80 gal/ton).

Availability of field residue WSU Cook Agronomy Farm, Pullman, WA

Soil Degradation:? The downward spiral of soil degradation. Adapted From Topp et al., 1995

Switchgrass yields Table 1. Switchgrass yields for Kanlow and Cave in Rock across the U.S. Switchgrass cultivar State Kanlow (L) Cave in rock (U) ----- dry T ac -1 ----- Texas 4.5 2.4 Upper South 5.5 4.2 Alabama 8.3 4.2 Iowa 5.8 -- Nebraska 9.2 7.3 Oklahoma 8.1 -- Washington* 14.0 9.4

Energy flow Table 3. Energy flow In producing ethanol from corn grain, corn stover, wheat straw and switch grass under irrigation. (After McLaughlin and Walsh, 1998) Process Crop Production a 30.3 37.4 37.4 28.3 --------------- GJ ha -1 yr -1 -------------- Biomass energy b 257.8 315.8 240.7 521.6 Energy ratio c 7.0 8.4 7.8 17.2 Ethanol Production d Corn (grain) 54.2 Corn (stover) 10.3 Wheat (straw) 10.3 Switchgrass 10.3 Energy in ethanol e 126.4 75.4 52.3 221.8 Total energy ratio f 1.37 1.58 1.35 5.46 Net energy gain g 37% 58% 35% 446% a Crop production based on budget data from USDA, 2002. b Biomass energy based on crop yield data. C Biomass energy/production energy. d Processing distribution energy, credits for co-products of corn and combustion of lignin from switchgrass. e Ethanol yields, 23.3 MJL -1, assumed %60 removal of corn stover and wheat straw. f Total output energy/input energy.

Soils: Sands to silt loams; SOC ranges 0.4 to 1.0% soil Elevation: 300 900 ft; Precipitation: 7.5 in. MAT: 50.9 o F FFD: 170 d Ellensburg Quincy Moses Lake WSU-Othello Field Site Royal City Mattawa Othello WSU-IAREC Field Site Prosser Tri-cities ARS Field Site Walla Walla Boardman Hermiston

Biomass Trials:Wheat, Corn, Switchgrass Biomass trials at the USDA-ARS Integrated Cropping Systems Research Field Station, Paterson, WA and estimates of acres needed to support a 20 M gallon ethanol facility. Crop Cultivar Biomass Yield T acre -1 Ethanol Yield gal ac -1 Acres support a 20 M gal Facility % of Planted Crop Acreage Wheat (straw) *5.8 400 83, 300 62.7 Corn (grain) *5.6 515 34, 500 55.2 Corn (stover) 8.4 580 71,800 82.1 Corn (grain+stover) 14.0 1095 23, 300 32.9 Switchgrass (3 rd yr) Cave in Rock (U) 9.1 728 27, 475 16.7 Shawnee (U) 10.5 840 23, 800 14.4 Kanlow (L) 14.0 1020 19, 600 11.9 *Yields from wheat and field corn trials were 148 and 200 bu ac -1, respectively. Estimated ethanol yield from wheat straw and corn stover was 69 gal/t, from corn grain was 103 gal/t and switchgrass biomass was 80 gal). Assumes 60% removal of wheat and corn residues. Percentage of hectares needed are based on data reported in the WA. Ag. Stats. for irrigated wheat (WW, SW), field corn and forage (alfalfa/hay).

N-Uptake of Switchgrass System Yield Range N uptake T ac -1 lb ac -1 1-cut 3-9 50-300 2-cut 5-9 50-200 2-cut split 5-14 100-300 No clear relationship between fertilizer N rate and N uptake Yield and nutrient uptake is site specific, depending on cultivar, soils, climate and rates of fertilization. Fertilizer recommendations, typically 50-100 lb N ac -1

Objective To determine switchgrass biomass production, nutrient concentration and response of switchgrass to N fertilization grown under irrigation. Few studies on N nutrition of switchgrass have been done in soilless medium where N availability is more readily defined or plants that are solely dependent upon N applied Parrish and Fike, 2005. CRPS.

USDA-ARS Integrated Cropping Systems Research Field Station, Paterson, WA Switchgrass Trials Study initiated in 2004 (taken out of shrub-steppe 2002) Split-plot in randomized complete blocks w/ 7 reps - main plot was switchgrass cultivar Kanlow, Shawnee, Cave in Rock - the sub-plot fertilization rate. (split appl.) 100 lb N ac -1, 200 lb N ac -1 ½ prior to breaking dormancy, ½ after 1 st cut 57 lb P 2 O 5 ac -1, 200 lb K 2 O ac -1, 20 lb S ac -1, and 1.0 lb B ac -1 - Irrigation ~25 in y -1 Measurements: - Aboveground biomass - Soil N pools (TN, NH 4, NO 3 ) - Root biomass - Tissue N & C by dry combustion - Macro- & micro-mineral composition by ICP

Switchgrass Variety Trials: Biomass 16 USDA-ARS Integrated Cropping Systems Research Field Station, Paterson, WA Yield (Dry T ac -1 ) 14 12 10 8 6 4 2 Establishment year Kanlow Shawnee Cave in Rock Cool Season Grasses Alfalfa 0 2004 2005 2006 2007 Year 2008 2009 Sum of Two Annual Harvests

Switchgrass Yield by Fertilizer N Rate (2006) 12 Aboveground Biomass (T acre -1 ) 10 8 6 4 2 Kanlow Shawnee Cave in Rock 0 0 50 100 150 200 Seasonal N Fertilizer Rate (lbs N ac -1 )

Aboveground Biomass and N Content 2006 Harvest 0 lb N ac -1 Cultivar Harvest Date Yield (DM) N Conc. Total N T ac -1 % lb ac -1 Kanlow 13 Jul 1.5 a 0.98 a 29 a Shawnee 1.7 a 1.16 a 39 a Cave in Rock 1.6 a 1.14 a 38 a Kanlow 10 Oct 0.5 a* 0.58 a* 5.8 a* Shawnee 0.5 a* 0.42a* 4.2 a* Cave in Rock 0.6 a* 0.47 a* 5.6 a*

Aboveground Biomass and N Content 2006 Harvest 100 lb N ac -1 : split appl. 50 lb N ac -1 Cultivar Harvest Date Yield (DM) N Conc. Total N T ac -1 % lb ac -1 Kanlow 13 Jul 5.3 a 1.33 a 140 a Shawnee 4.6 ab 1.31 a 119 b Cave in Rock 3.9 b 1.50 a 115 b Kanlow 10 Oct 4.1 a* 0.82 a* 67 a* Shawnee 3.5 ab* 0.79 a* 55 a* Cave in Rock 2.5 b* 0.57 b* 28 b* 200 lb N ac -1 Yields were ~ 1 T ac -1 higher

Switchgrass Root Biomass

Switchgrass Trials: Root Biomass 0 6 Depth (inches) 12 18 24 30 Kanlow Shawnee Cave in Rock 36 0 1000 2000 3000 4000 5000 Root DM (lb ac -1 ) Figure 2. Root biomass (DM dry matter) in increments to 0.9 m depth for Kanlow, Shawnee and Cave in Rock cultivars sampled in 2006. Root biomass was plotted at the bottom of each sampling increment. Horizontal bars are standard errors of the mean.

Root Biomass and N Content Table 2. Profile root biomass and root N of three year old switchgrass stands collected on 30 October 2006. Cultivar Root Biomass N Conc. Root N T ac -1 % lb ac -1 Kanlow 3.7 (0.5) 1.17 (0.1) 90.6 (12) Shawnee 4.1 (0.3) 1.31 (0.1) 108.0 (10) Cave in Rock 4.7 (1.2) 1.21 (0.1) 118.1 (30) Root biomass includes both live and dead roots. Crown biomass not included. Standard error of the mean in parentheses. Values are average of four replicates.

N Budget Table 3. Cumulative sources and sinks for soils with 100 lb N ac -1 y -1 for 2004-2006 crop years. Sources Sinks Cultivar Soil Fert Soil N Soil Total Plant N 2004 2006 Total Diff Soil Test N N-Min N AGBM Root N Test ------------------------------------ lb N ac -1 ------------------------------------- Kanlow 80 200 188 468 402 90 492-24 18 Shawnee 80 200 188 468 380 108 488-20 33 Cave in Rock 80 200 188 468 304 118 422 +46 73 ~ 20-30 lb N ac -1 can be added through irrigation waters. ~ 4 lb N ac -1 can be added by air deposition.

Nitrogen Uptake Dry matter produced per unit of N in 2006. Cultivar AGDM Roots TDM ApSN TDM/N 2006 -------- T ac -1 -------- lb ac -1 lb DM / lb N Kanlow 9.4 3.7 13.1 243 108 Shawnee 8.0 4.1 12.1 243 100 Cave in Rock 6.3 4.7 11.0 243 90 ApSN applied and soil N: 80 lbs in soil profile; 100 lbs added as fertilizer; 60 lbs mineralized. ~0.010 lb N to produce a lb of biomass.

Nitrogen Uptake Table 5. Comparison with 2 sites in Oklahoma. N Rate Measured Predicted T ac -1 Uptake Yield Uptake Chickasha, OK lb ac -1 T ac -1 lb ac -1 100 160.2 6.5 130.0 200 161.5 6.6 145.2 400 194.8 7.8 171.6 Perkins, OK 100 59.9 4.2 92.4 200 86.5 4.7 94.0 400 114.7 5.0 100.0 ~0.010 lb N to produce a lb of biomass.

Added 200 lb N ac -1 10% 15N enrichment So 20 lbs was labeled. Nitrogen cycling in switchgrass using stable isotopes IAREC, Prosser Warden Silt Loam

Nitrogen Uptake Total N uptake N uptake lbs/ac 180 160 140 120 100 80 60 40 20 0 Blackwell Shawnee biomass tons/ac 1.99 1.73 7.76 7.57 2007 2009

Switchgrass: Nutrient Removal Estimate of nutrient removal based on 2006 production levels. Biomass yield: 10 T acre -1 (Kanlow cultivar) Planted: 24,750 acres (to support 20 gal facility) Total Biomass Harvested: 250,000 T Nutrient % lbs acre -1 T* Nitrogen 1.22 245 3,050 Phosphorus 0.15 31 375 Potassium 1.51 305 3,775 Calcium 0.27 54 675 Magnesium 0.24 48 600 Sulfur 0.05 10 125 Other (Fe, B, Mn, Cu, Zn) <0.04 8 100 *Tons of nutrient delivered to ethanol facility. Lignin - ~15% = 37,500 T ---- Burned for energy, other products?

Corn Stover Biomass

Table 5. Average export of nutrients from soil with removal of corn stover and wheat residues. Nutrient Corn (lbs/a) Wheat (lbs/a) N 115.00 (grain 136) 27.20 P2O5 40.00 6.80 K2O 167.00 47.60 Ca 30.00 8.16 Mg 23.00 4.08 S 16.00 6.80 Cu 0.06 0.01 Mn 1.72 0.22 Zn 0.34 0.20 from Hatfield, 2008, Fluid Journal As with switchgrass nutrients would be delivered to the refinery, potential for nutrient recovery and reuse.

USDA-ARS Integrated Cropping Systems Research Field Station, Paterson, WA Switchgrass Trials

Characteristics of C 3 and C 4 Plants C 3 C 4 Examples CO 2 fixed δ 13 C Range δ 13 C Avg. Wheat, oats, Rice, oaks 3-C PGA -23 to -40-26 Corn, sudangrass Switchgrass 4-C malic, aspartic -9 to -19-13 δ 13 C = 13 C/ 12 Csample 13 C/ 12 C standard 13 C/ 12 C standard

Switchgrass Trials: C Sequestration Table 3. Switchgrass dry matter, root C, soil organic C, δ 13 C and percent of C derived from C 4 cropping for the surface foot. Switchgrass Soil AGDM Root Total Percent C derived Cultivar C C Plant C SOC δ 13 C C 4 -C from C 4 ------------------ lbs acre -1 --------------- % lbs acre -1 Kanlow 9,105 3,312 12,417 9,750-22.1 23.5 2,290 Shawnee 7,511 3,828 11,339 9,470-22.2 22.8 2,150 Cave in Rock 6,715 4,436 11,151 8,435-21.8 25.8 2,180 Native ------------------- lbs acre -1 --------------- % lbs acre -1 Native 1,835 3,300 5,135 8,150-25.2 0 0 AGDM above ground dry matter. Average of 0-6 and 6-12 in. depth increments. Above and belowground biomass for a native sagebrush-bunchgrass site on the Hanford Reservation in Eastern WA (Rickard and Vaughan, 1988). Native plant residues were assumed to be 42 % C on a dry weight basis.

Biomass Trials:Wheat, Corn, Switchgrass

Energy or Feed? First yr 3 T/acre Fourth yr 14 T/acre

hal.collins@ars.usda.gov Questions?

Switchgrass Trials: Irrigation 26.5 in Period for Water Savings 17.0 in 10 Mg ha -1 9.5 in 12 Mg ha -1

Questions?