Soil & Environmental Responses to Dedicated Bioenergy Crops on Marginally Productive Croplands Humberto Blanco, Associate Professor, Applied Soil Physics and Soil Management, Department of Agronomy and Horticulture, University of Nebraska-Lincoln, NE Robert Mitchell, Research Agronomist, USDA-ARS Virginia L. Jin, Research Soil Scientist with USDA-ARS

THREE EXPERIMENTS Perennial warm-season grasses and corn with and without stover removal and cover crops. Start: 2012. Perennial grass monocultures and polycultures. Experiment start: 2009. Nitrogen, phosphorus, and potassium fertilization of switchgrass “Shawnee” Experiment start: 2010. Location of the 3 experiments: UNL Agricultural Research Development Center (ARDC)

BIOFUELS NEED TO BE DONE RIGHT Need to develop biofuels from systems that: Reduce net emissions of GHG. Maintain or increase soil C pools. Reduce soil erosion Do not compete with food crops Improve wildlife habitat and diversity.

Aerially seeded cover crops before corn harvest Strategies to ameliorate possible negative effects of residue removal effects on soil and environment Aerially seeded cover crops before corn harvest

Improvement in Soil Properties, wildlife habitat, reduced soil erosion, water quality Reduced bulk density, increased porosity, increased water retention, increased soil aggregate stability, and enhanced soil organic C aacumulation

What is the effect of dedicated bioenergy crops on soil properties when grown in marginally productive croplands? Soil physical processes and properties. Water erosion. Wind erosion. Soil carbon sequestration. Others

EXPERIMENT I Perennial warm-season grasses and corn with and without stover removal and cover crops. Start: 2012. Ocassionally floded 2 acre whole plots 4 Feedstocks Big bluestem – Bonanza/Goldmine Switchgrass – Liberty Low diversity mix (BB, IN, SO) Corn (150 lbs N/acre) 3 replicates (1 acre subplots 2 N fertilizer rates (perennial grass) N1 = 50 lbs N/acre, N2 = 100 lbs N/acre No stover removal or 50% removal on ½ & add triticale cover crop (corn) 40% OF THE SITE IS MARGINALLY PRODUCTIVE DUE TO PONDING; 29% IS ERODED WITH 2-6% SLOPE Eroded

Spring 2014 SOIL PROPERTIES MEASURED SOIL DEPTH RATIONALE Nutrients 0-7.5, 7.5-15, 15-22.5 cm Changes in soil fertility Soil organic C Changes in soil C Particulate Organic Matter Changes in SOM dynamics Wet aggregate stability Risks of water erosion Dry aggregation 0-5 cm Risks of wind erosion Saturated hydraulic conductivity Intact cores: 0-7.5, 7.5-15 cm Changes in water flow and retention Moisture retention characteristics Soil compactiblity Changes in soil’s susceptibility to compaction

Water-stable soil aggregate stability Soil compaction parameters

Where is the risk of water erosion higher?

Where is the risk of wind erosion higher?

WATER EROSION RISKS WIND EROSION RISKS Perennials reduce water erosion risks WATER EROSION RISKS Residue removal increases water erosion risks Perennials reduce wind erosion risks WIND EROSION RISKS Residue removal increases water erosion risks

EXPERIMENTS II: Perennial grass monocultures and polycultures EXPERIMENTS II: Perennial grass monocultures and polycultures. Experiment start: 2009. EXPERIMENTS III: Nitrogen, phosphorus, and potassium fertilization of switchgrass “Shawnee” Experiment start: 2010. We studied changes in root biomass, soil organic C, total N, C:N ratio, water-stable aggregates, P, K, and bulk density after 5 yr in warm-season grass monocultures and polycultures and after 4 yr of inorganic fertilization of switchgrass.

Experiment II: Grass Monocultures and Polycultures Experiment consisted of five high yielding perennial grass monocultures and polycultures. Monocultures 1. Switchgrass “Shawnee”, 2. Switchgrass “Kanlow N1” 3. Miscanthus Polycultures Big bluestem (Goldmine) + indiangrass (Warrior) + switchgrass (Shawnee) Big bluestem (Bonanza) + indiangrass (Scout) + switchgrass (Shawnee)

Experiment III: Fertilization and Harvest Date Two factors: two switchgrass harvest dates (August and November) and NPK fertilizer rates N (0, 60, and 120 kg ha-1): Main plots P (0, 22, and 44 kg ha-1): Split plots K (0, 11, and 22 kg ha-1): Split-split plots. Four 100 cm long soil cores were sampled in spring 2014.  The soil cores were sliced at: 0- 10, 10-20, 20-40, 40-60, and 60-80 and 80-100 cm depths.

Root biomass and soil C did not differ among perennial grass monocultures and polycultures after 4 yr. Mean root biomass was 6.75 Mg/ha in the 0 to 10 cm depth and 2.5 Mg/ha in the 10 to 100 cm depth. Inorganic (NPK) fertilization of switchgrass had no effect on root biomass, soil organic C, total soil N, water- stable soil aggregates, bulk density, and soil pH. Significant differences may develop in the long term.

TAKE HOME MESSAGE Dedicated energy crops such as perennial grasses maintain or improve soil properties and environmental quality compared with crop residue removal in marginally productive lands. Monocultures and polycultures appear to have similar effects on root biomas, soil C, total, and other properties in the short term. Inorganic fertilization of switchgrass may not affect soil properties in the short term.

OUR BIG THANKS TO THE NC-SUN GRANT CENTER FOR FUNDING THIS PROJECT. ACKNOWLEDGEMENT OUR BIG THANKS TO THE NC-SUN GRANT CENTER FOR FUNDING THIS PROJECT. Field and lab team: Leonard Kibet, postdoctoral researcher Brian E. Maust, research technologist Bulent Sezer (research scientis Dallas M. Williams, undergraduate student Carolyn Fox, undergraduate student Liao Yi-nan. Northwest A&F Univ., China Yang Ming. Northwest A&F Univ., China Brian Maust, research technologist Liao Yi-nan and Yang Ming. Northwest A&F Univ., China From left to right Rob Mitchell (Co-PI), Leonard Kibet, (post doc), Bulent Sezer (research scientist)

Publications/Presentations/Training: ITEM NUMBER Abstracts    4 (Meetings in USA and Germany). Peer Reviewed Publications  2 in preparation. The first one will be submitted on March 31, 2015. The second in July 30, 2015 Professional Presentations 4 presentations (Summer Ressearch Symposiums at UNL, Long Beach, CA, Nov. 2-5, and Liepzig, Germany, Nov 23-25) Post-Docs Supported 1 postdoctoral researcher (Dr. Leonard Kibet): Two poster presentations. Prepared one manuscript almost ready for submission. Undergraduate Students Supported 4 undergraduate students Investigators Supported  1 Research Technologist (Brian Maust)

Invited as keynote speaker to the “Biomass for energy – Lessons from the Bioenergy Boom” Conference, Leipzig, Germany, 24-25 November, 2014. Organized by the Department of Bioenergy of the Helmholtz Centre for Environmental Research (UFZ) in cooperation with Deutsches Biomasseforschungszentrum (DBFZ)

SSSA Division: Soil & Water Management & Conservation Oral Session Business Meeting--Soil & Water Management & Conservation Organizer: David R. Huggins Oral Session Developing Sustainable Bioenergy Cropping Systems: I Organizer: Humberto Blanco Oral Session Developing Sustainable Bioenergy Cropping Systems: II Organizer: Humberto Blanco Poster Session Developing Sustainable Bioenergy Cropping Systems: III Organizer: Humberto Blanco

TIME FOR QUESTIONS