Fertility Issues in Switchgrass Production Joint Meetings of SERA-ieg 6, NEC-17 and NCRA Nashville, Tennessee Donald Tyler University of Tennessee

DOE UT Switchgrass Project Burt English (Co-director) Daniel DeLaTorre Ugarte (Co-director) Chris Clark Clark Garland Ken Goddard Kim Jensen Roland Roberts Larry Steckel Donald Tyler Marie Walsh

Sources of Ethanol in USA Corn – starch based Sugarcane – sugar – (Brazil) Corn – limited suitable land - competes for corn as food - high inputs - FFE of 1.1 to 1.2 to 1

Cellulosic Ethanol Wood wastes (expensive) Corn and wheat stover (limited) Crops: Switchgrass (Panicum virgatum) FFE 5.2 to 1 Giant miscanthus Hybrid poplar (North USA)

Status No surplus or production advantage for corn or soybean production in TN. Our competitive advantage is perennial switchgrass. Thrust for cellulosic ethanol production and use at national and state level. Lack of efficient switchgrass production strategies in TN.

Switchgrass Perennial Relatively low input crop Other species & biomass sources Competitive advantage in the Southeast Native species Planted with seed No specialized planting or harvesting equipment

Dedicated Energy Crops Estimated using POLYSYS analytical system, Daniel De La Torre Ugarte and Burton English

Dedicated Energy Crops Estimated using POLYSYS analytical system, Daniel De La Torre Ugarte and Burton English 160 million tons of switchgrass from 19 million acres

Dedicated Energy Crops Estimated using POLYSYS analytical system, Daniel De La Torre Ugarte and Burton English 362 million tons of switchgrass from 35 million acres

Research in Progress Soil / landscape suitability Seeding / nitrogen rate interactions Cultivar selection Weed control strategies On – farm demonstrations Switchgrass production:

Seeding Rate – Nitrogen Study Nitrogen rates: 0, 60, 120, 180 lbs. N per acre as NH 4 NO 3. Spring applied starting the 2 nd season. Seeding rates: 2.5, 5.0, 7.5, 10.0 and 12.5 lbs. PLS per acre. Alamo variety

Nitrogen Being evaluated Responses vary Presently 60 lbs. N/A after first year

Seeding Rate 60 lbs. N/A 11.0 a 10.0 a 10.1 a 11.5 a 9.6 a 11.3 ab 10.6 ab 12.6 a 10.5 b DM Yield in T/A Lbs./ A PLS Well drained to moderately well drained level upland 180 lbs. N/A 0 lbs. N/A 8.5 a 9.4 a 8.9 a 9.2 a 7.7 a 120 lbs. N/A 10.8 a 10.7 a 11.3 a 10.7 a 10.0 a Values within a nitrogen rate followed by the same letter are not significantly different at P = 0.05 <

Seeding Rate 60 lbs. N/A 2.4 b 4.6 a 4.5 a 4.8 a 3.8 ab 5.1 b 6.8 a 7.2 a 7.0 a DM Yield in T/A Lbs./ A PLS poorly drained floodplain 180 lbs. N/A 0 lbs. N/A 2.6 b 3.1 ab 3.0 ab 3.4 ab 3.8 a 120 lbs. N/A 4.0 a 5.2 a 5.0 a 5.4 a 5.2 a Values within a nitrogen rate followed by the same letter are not significantly different at P = 0.05 <

Phosphorus Removed tissue concentration ( 8 locations over 5 years) 0.09% P 8 tons to the acre = 14 lbs P/A or 32 lbs P 2 O 5 Low testing (Mehlich 1) = 40 lbs P 2 O 5 /A

Potassium Removal tissue concentration (8 locations over 5 years) 0.52% K 8 tons/A = 83 lbs K/A or 100 lbs K 2 O/A Low testing (Mehlich 1) = 80 lbs K 2 O/A

Soil Acidity No lime recommended pH 5.0 and above O. M. complexing Al and Mn

Summary Establishment – 6 lbs./A PLS – Tilled or no-tilled ½ inch or less coverage. Fertilization – 60 lbs./A N after 1 year – 40 lbs./A P 2 O 5 & 80 lbs./A K 2 O at low soil test. Weed Control – Broadleaf available – Grass control in process. Harvest – Big round or square bales – Modules? – Stack storage? – In field processing?