RESULTS MATERIALS AND METHODS Assessing and maximizing ecosystem services provided by the soil food web in long-term organic and transitioning farming systems Bal, Harit K. 1, Kuhuk Sharma 2, Khandakar R. Islam 3, Edward L. McCoy 4, Subbu Kumarappan 5, Alan Sundermeier 6 and Parwinder S. Grewal 1,7 1 Department of Entomology, OARDC, The Ohio State University, Wooster, OH 44691; 2 Environmental Science Graduate Program, OARDC, The Ohio State University, Wooster, OH 44691; 3 OSU South Centers, Piketon, OH 45661; 4 School of Environment and Natural Resources, OARDC, The Ohio State University, Wooster, OH 44691; 5 Agricultural Technical Institute, Wooster, OH 44691; 6 Ohio State University Extension, Wood County, Bowling Green, OH 43402; 7 Current address: Department of Entomology and Plant Pathology, The University of Tennessee, Knoxville, TN ABSTRACT Soil management could enhance ecosystem services provided by the soil food web and help develop sustainable organic agro-ecosystems. We hypothesized that a combination of no-till, multi-functional cover crops, and organic amendments (mined Zeolite) would produce greater ecosystem services by increasing soil food web structural and functional complexity, reducing insect-pest pressure, enhancing arthropod diversity and natural belowground biocontrol activity in long-term organic farms at Bowling Green (BG) and West Salem (WS) and transitioning farm at Piketon (PI) in Ohio. We compared 2 levels of tillage (conventional till, CT and no-till, NT), 3 levels of zeolite (0, kg/ha) and 3 crop phases (corn-soybean-spelt) to evaluate the soil food web (represented by nematode community), pest/predator abundance using sweep nets, arthropod diversity using Pitfall traps and biocontrol activity using in-situ baiting technique. Nematode-faunal analysis showed that the soil food web in WS and BG was significantly enriched (Enrichment Index, EI: 40-54%), structured (Structure Index, SI: 45%) and mature (Maturity Index, MI: 2-2.3%) than in PI (EI: 42%; SI: 22%; MI: 1.9%), with greater fungal decomposition channels in PI (Channel Index, CI > 50%) and bacterial in WS and BG (CI < 50%). There was significantly greater biocontrol activity, predator abundance and arthropod richness at WS and BG whereas PI had greater arthropod diversity and plant damage. Although treatment effects were not detected, significantly greater predator abundance in NT than CT provides encouraging evidence of improving ecosystem services in no-till organic agro-ecosystems. Further, long-term soil management is required to establish enhanced ecosystem services provided by the soil food web. CONCLUSIONS  Soil management with a combination of no-till, multifunctional cover crops and soil amendment (zeolite) showed greater ecosystem services provided by the soil food web in long-term organic farms than the transitioning experimental farm.  This study gave useful insight into soil food web complexity, natural belowground biocontrol activity, pest pressure and arthropod diversity in differently managed organic farms during the 1 st year of investigation.  Although treatment effects were not detected, significantly greater predator abundance in NT than CT provides encouraging evidence of improving ecosystem services in no-till organic agro-ecosystems.  We suggest long-term soil management to establish enhanced ecosystem services provided by the soil food web. REFERENCES Bongers T The maturity index: an ecological measure of environmental disturbance based on nematode species composition. Oecologica 83:14–19. Briar SS, Grewal PS, Somasekhar N, Stinner D, Miller SA Soil nematode community, organic matter, microbial biomass and nitrogen dynamics in field plots transitioning from conventional to organic management. Applied Soil Ecology 37:256–266. Ferris H, Bongers T, de Geode RGM A framework for soil food web diagnostics: extension of the nematode faunal analysis concept. Applied Soil Ecology 18:13–29. Frey SD, Elliot ET and Paustian K Bacterial and fungal abundance and biomass in conventional an no-tillage agroecosystems along two climactic gradients. Soil Biology and Biochemistry 31: Hendrix PE, Parmelee W, Crossley Jr DA, Coleman DC, Odum EP and Groffman PM Detritus food webs in conventional and no-till agroecosystems. Bioscience 36: Acknowledgements: We thank Dr. Ruisheng An, Amr Badawy, Muhammad Raheel for their valuable help. BACKGROUND  Ecosystem services provided by the soil food web are the basis of sustainability in all terrestrial ecosystems, but these webs in agroecosystems are degraded, short and dominated by opportunists at the entry level.  Previous research has shown the negative impact of tillage on the structural and functional complexity of the soil food web (Hendrix et al. 1986; Frey et al. 1999; Briar et al. 2007).  With growing research on the environmental benefits of organic farming, development of alternative soil management strategies to avoid the negative effects of tillage on soil health could help in developing sustainable and environmentally sound organic agro-ecosystems.  Therefore, our long-term goal is to build highly efficient organic farming systems that rely more heavily on the ecosystem services provided by the soil food web and generate positive environmental outcomes. OBJECTIVE Evaluate the effects of various combinations of conservation tillage practices, multi-functional cover crops and a soil amendment (Zeolite) on the following soil health parameters: - Structural and functional diversity of the soil food web- Pest and Predator abundance - Arthropod diversity- Natural biocontrol services HYPOTHESIS: We hypothesized that a combination of no-till, multi-functional cover crops, and organic amendments will produce greater ecosystem services by increasing soil food web structural and functional complexity, reducing insect-pest pressure, enhancing arthropod diversity and natural belowground biocontrol activity in long-term organic and transitioning farming systems. Soil food web complexity (Nematode-faunal analysis) Fig.2. Nematode-faunal analysis showing differences between tillage and sites in the abundance of nematodes belonging to 5 trophic groups [Bacteria feeding (BF), fungus feeding (FF), plant parasitic (PPN), predatory (PR), omnivorous (OM)] and indicator indices [Maturity index (MI), plant-parasitic index (PPI), combined maturity index (CMI), enrichment index (EI), structure index (SI) and channel index (CI)]. Soil food web complexity Represented by nematode-faunal analysis. Nematodes were extracted from 10 g composite soil sample per plot using the Baermann funnel technique and identified to genus level. Each nematode genus was classified into 5 tropic groups: bacteria feeding, fungus feeding, plant parasitic, predatory, and omnivorous. Calculated nematode community indices: maturity index, plant-parasitic index, combined maturity index, enrichment index, channel index and structure index (Bongers 1990; Ferris et al. 2001) Insect-pest pressure Stand Counts (Corn and Soybean): Chose 2 random 10’ transects per plot. Recorded total plant count in each transect, type of damage and number of damaged plants. Pest/Predator Abundance (Soybean): Sweep net sampling between crop rows. 10 sweeps per plot, collected in one plastic bag. Insect-pests and predators were identified and counted. Experimental Design Research Sites in Ohio: –Long-term Organic farms: Bowling Green (Hirzel Research Site) West Salem (Farmer’s field) –Transitioning Experimental farm (Piketon) Experimental Design: RCB Treatments: –2 Levels of Tillage: Conventional till (CT); No-till (NT) –3 Levels of Zeolite: 0, 50 and 100 Kg/ha –3 Crop phases: Corn, soybean, spelt (Each crop planted each year) Multi-functional cover crops: –Winter pea and crimson clover (N-fixers) –Oats and cereal rye (weed suppressors) –Oilseed radish (reactive N and P recycler, compaction alleviator, and disease minimizer) Fig.1. Research sites in Ohio: Bowling Green (BG), West Salem (WS) and Piketon (PI). Natural belowground biocontrol In-situ baiting technique using last instar wax moth Galleria mellonella larvae as bait insects (5/bait trap). Buried 2 bait traps/plot, cm below the soil surface for 48hr. Collected baited insects in Petri dishes lined with filter paper and examined for ant infestation and bacterial, fungal and entomopathogenic nematode (EPN) infections. Arthropod Diversity Installed 2 Pitfall traps per plot for 48 hr. Preserved arthropods in 70% ethanol; identified to order or family level. Calculated Shannon Diversity Index, Evenness Index and Margalef Richness Index. Data Analysis General linear model was used to analyze all the data with significant treatment differences at P < 0.05 (Minitab 16). ab c a b c a a b a a b b b b a aaa bb a a a a bb a a b a b b Insect-pest/Predator Abundance Insect-pest pressure Fig.3. Insect-pest/predator abundance in soybean and insect-pest pressure in corn-soybean in CT vs NT and at 3 sites, Bowling green (BG), Piketon (PI) and West Salem (WS). Predator abundance was significantly greater in NT than CT. * a b b b b a a a b Arthropod Diversity Natural belowground biocontrol ab a b a bb a b c * a b b a b a b b a b a b c Fig.5. Natural belowground biocontol activity of bacteria, fungi, ants and entomopathogenic nematodes (EPNs) in CT vs NT and at 3 sites, Bowling green (BG), Piketon (PI) and West Salem (WS). Fig.4. Arthropod diversity indicated by indices: Shannon diversity index (ShI), Evenness index (EI) and Margalef richness index (RI) in CT vs NT and at 3 sites, Bowling green (BG), Piketon (PI) and West Salem (WS).