1. High Biomass Cover Crops and Organic Mulch Effects on Yields, Soil Carbon, & Weed Populations during No-Till Herbicide-Free Collard Production Michael J. Mulvaney Auburn University

2. Introduction Conservation tillage offers: –↓ Erosion –↑ SOM –↑ Soil moisture –Improved soil structure –Soil temperature moderation Kip Balkcom, 2008

3. Problem #1 problem: Weed suppression How to suppress weeds without tillage or herbicides?

4. Solution? High biomass cover crops (killed mulches) Mulch Ted Kornecki, 2008

5. Rationale Combine cover crops and mulches Improve soil quality on productive field Effects on: –Yields, soil, weeds

6. Objective Determine the effects of organic mulches and forage soybean as a summer cover crop on: SOC C mineralization Total soil N Aggregate stability Collard yield Weed populations in a no-till system without the use of herbicides during limited-input fall collard production

7. Methods 3 years: 2005-2008 Central-Eastern AL 2x4 RCB: 2 summer cover crops: –Forage soybean, weed fallow 4 organic mulches: –Lespedeza, mimosa, straw, control –6.7 Mg ha -1 yr -1 (3 t/ac/yr)

8. Cropping Schedule JanFebMarMayJunJulSepAprOctNovDecAug Soybean or Control CollardsRye Mulch application

9. Methods C & N: –Dry combustion C mineralization: –Lab incubation –NaOH trap Aggregate stability: –Water immersion Yield: –65 DAP –2.8 m 2 (30 ft 2 )

10. Methods Weed coverage –Transects 50 count transects 2x per plot Classified: –Broadleaves –Grasses –Sedges –Soil –Identified to species level 2x in 2008

11. Statistics SAS: –Proc Means: Means and standard errors –Proc Glimmix: Model variable selection –95% CL for treatment comparisons

12. SOC after 3 yrs ABCBCC

13. Soil organic carbon

14. ABCBCDD

15. Other results C mineralization –No treatment differences, 0-10 cm depth –Ave: 12.1 mg C kg -1 soil day -1 over 34 d @ 25 ºC Aggregate stability –No treatment differences 0-5 cm depth –Ave: 91% stable

16. Yields Collard Yields: –No treatment differences –Ave in SC (2001) 12,000 lbs/ac –Ave: 17,900 kg ha -1 = 16,000 lbs/ac –Assuming 25% waste & 1.1 lbs/bunch: ATL market, Nov. 18, 2009: –25 lbs/ctn: $12/ctn $5,760/ac – No premium assumed

22. Conclusions: Soils Conversion to no-till increased SOC Forage soybean did not affect SOC, TSN Forage soybean decomposes quickly C mineralization, aggregate stability, yields not affected by mulching or forage soybean

23. Conclusions: Weeds Forage soybean does not effectively suppress weeds Broadleaves and sedges suppressed under high biomass no-till Grasses control: highly variable Population shifts from broadleaves toward grasses

24. CARBON AND NITROGEN MINERALIZATION AND PERSISTANCE FROM ORGANIC RESIDUES Objective: –To quantify mass loss and nutrient release rates from decomposing organic residues under conservation and conventional tillage.

25. Methods E.V. Smith Research Center Plant Breeding Unit –S. Tallassee, AL –Wickham fine sandy loam, 0 to 2 % slope –3 yrs in no-till Lespedeza, Mimosa, Oat Straw, Soybean Packed into litterbags –6.7 Mg/ha (3 t/ac)

26. Methods Randomized split-plot design Buried or surface-placed Retrieved periodically –0, 3.5, 7, 14, 28, 56, 112, 224, & 364 days after Oct. 7, 2007 Samples dried, weighed, analyzed for C and N Ash-free dry weight

27. Statistics –SAS Proc Mixed, Proc GLM –95% Confidence Level Regression: –Sigmaplot –Double exp. decay: Y = Ae -k1t + Be -k2t Time Mass or nutrient remaining

28. Mass remaining

30. Carbon remaining

33. Nitrogen remaining

35. LespedezaMimosaStrawSoybean Buried Season 126 216 Surface Season 11820322 Seasonal N Mineralization (kg ha -1 ), May 1 – Oct. 7

36. Assumes decay models valid >1yr LespedezaMimosaStrawSoybean Buried Season 126 216 Season 291025 Surface Season 11820322 Season 2111339

37. LespedezaMimosaStrawSoybean Buried Season 126 216 Season 291025 Season 33411 Surface Season 11820322 Season 2111339 Season 37924 Seasonal N Mineralization (kg ha -1 ), May 1 – Oct. 7 Assumes decay models valid >1yr

38. LespedezaMimosaStrawSoybean Buried Season 126 216 Season 291025 Season 33411 Year 3 total3840522 Surface Season 11820322 Season 2111339 Season 37924 Year 3 total3642835 Seasonal N Mineralization (kg ha -1 ), May 1 – Oct. 7 Assumes decay models valid >1yr

39. Conclusions Mass/nutrient loss is faster with buried residue Surface residue may act as slow-release fertilizer More OC & N accumulation from surface residue over time Nutrient fate is not determined in this study

40. Acknowledgements Dr. Wes Wood Committee: –Dr. Kip Balkcom –Dr. Joe Kemble –Dr. Dennis Shannon Dr. Andrew Price SARE Auburn University

41. Part II: Qualifications SANREM CRSP Phase IV: Increase smallholder food security through conservation agriculture production systems.

42. Goals Develop conservation agriculture production systems for rain-fed, staple crop, smallholder production systems; and Identify and test effective strategies through which smallholders can transition to sustainable CA.

43. Qualifications PhD, Agronomy & Soils  No-till crop production  Vegetables & agronomic crops  Soil fertility management  C and N cycling in agroecosystems  Limited-input, smallholder food systems  BS, Organic chemistry  Knowledge of C rxns

44. Outside of dissertation  Soil H 2 O retention under no-till cover crops  Alley cropping  Gas emissions  J. Environ. Qual. 37:2022–2027 (2008)  Consulting, Agroinnovations, Inc.  C & H 2 O inventories on landscape levels  Sludge application  Land use maximization

45. Outside of dissertation  Auburn Community Garden Coordinator  Vegetable production for food insecure

46. International Development Agricultural Extension Volunteer U.S. Peace Corps, Bolivia: Jan. 2000-May 2002 –Managed, implemented ag projects in Quechua villages –Wrote grants, budgets & progress reports

47. Animal Husbandry Vaccination of cattle, sheep & goats throughout region Castration of pigs and bulls

48. Pit Latrines ApicultureEducationGreenhouses

49. Water Systems Gravity systems built for 51 families in 2 communities Water used for irrigation &/or personal use

50. Central China May-June 2009 Northwestern A&F University

51. International experience 40+ countries on 5 continents

52. Foreign Languages English (Native speaker) Spanish (Proficient) Quechua (Working knowledge) Vietnamese (One year university level)

53. Conservation Agriculture Conservation tillage Alley cropping Limited input agriculture Nutrient management Water management Crop rotations Weed management Pest management Gas emissions

54. Soil C Sequestration/Cycling Developed soil C inventories Modeled C sequestration in no-till systems Organic C decomposition Knowledge of organic C rxns

55. Communication Skills Peer reviewed publications: Michael J. Mulvaney*, A.J. Price, and C.W. Wood. Cover crop residue and organic mulches provide herbicide-free weed control during no-till collard production. Currently under review, Journal Sustainable Agriculture. Michael J. Mulvaney*, K.A. Cummins, C.W. Wood, B.H. Wood, & P.J. Tyler. 2008. Ammonia emissions from field-simulated cattle defecation and urination. Journal Environmental Quality 37(6): 2022-2027. S.A. Pratt, M.F. Goble, M.J. Mulvaney & P.G.M. Wuts. 2000. Dialkylhydrazides for directed orthometalations. Tetrahedron Letters 41:3559. +4 more pubs from dissertation

56. Conference Presentations Mulvaney, M.J., C.W. Wood, and B.H. Wood. 2009. Conservation tillage effects on carbon, nitrogen and mass loss from organic residues. ASA-CSSA-SSSA International Annual Meetings, Pittsburgh, PA. Nov. 1-5, 2009. “Food Insecurity and the Auburn Community Garden” Seminar Series on Hunger Research and Intervention. Dept. of Nutrition and Food Science, Auburn University, Auburn, AL. Oct. 14, 2009. Mulvaney, M.J., C.W. Wood, and B.H. Wood. 2009. Persistence and nutrient release from organic mulches and cover crops. 106 th Southern Assoc. of Agricultural Scientists, Atlanta, GA. Feb. 1-3, 2009. “Food Security Issues Facing the Rural South” Panel presentation at the Professional Agricultural Workers Conference. Committee on the Role of Faith Based Organization in Rural Community Development, Tuskeegee University, Tuskeegee, AL. Dec. 8, 2008. Mulvaney, M.J., C.W. Wood, B.H. Wood, K.S. Balkcom, J. Kemble, and D. Shannon. 2008. High biomass cover crops and organic mulch effects on soil moisture and weed distribution during collard production. ASA-CSSA-SSSA Joint National Conference, Houston, TX. Oct. 5-9, 2008. Mulvaney, M.J., C.W. Wood, and B. Wood. 2008. Nutrient release rates from organic mulches and cover crops. Proc. 8th Annual Conservation Production Systems and Training Conference, Tifton, GA. July 29-31, 2008.

57. Conference Presentations Mulvaney, M.J., C.W. Wood, K.A. Cummins, B.H. Wood and P.J. Tyler. 2008. Ammonia emissions from grazing cattle. 18 th GSC Research Forum, Auburn, AL. Mar. 11-12, 2008. Mulvaney, M.J., K.A. Cummins, C.W. Wood, B.H. Wood and P.J. Tyler. 2008. Ammonia volatilization from field-simulated cattle defecation and urination. 105 th Southern Assoc. of Agricultural Scientists, Dallas, TX. Feb. 2-5, 2008. Mulvaney, M.J., C.W. Wood, K.S. Balkcom, B. Meso, and B. Wood. 2007. Effects of tillage, location and variety on nitrogen release from peanut residue. 17 th GSC Research Forum, Auburn, AL. Mar. 7-8, 2007. Mulvaney, M.J., K.S. Balkcom, C.W. Wood, B. Meso, and B. Wood. 2007. Effects of nitrogen, tillage and variety on nitrogen release from peanut residue under field conditions. Proc. 104th Southern Association of Agricultural Scientists, Mobile, AL. Feb. 3-6, 2007. Mulvaney, M.J., C.W. Wood, K.S. Balkcom, and B. Meso. 2006. Nitrogen release from peanut residue. In R.C. Schwartz, R.L. Baumhardt, and J.M. Bell (eds.) Proc. 28th Southern Conservation Systems Conf., Amarillo, Texas. June 26-28, 2006, USDA-ARS Conservation and Production Research Laboratory Report No. 06-1, Bushland, TX.

58. Awards  First Place, Graduate Oral Competition, Soils Division. Southern Assoc. of Agricultural Scientists. Atlanta, GA, Feb. 2, 2009  A. L. Smith Outstanding Graduate Student Award, Ph.D. candidate category, Dept. of Agronomy & Soils. Auburn University, AL. Jan. 16, 2009  Soil Science Society of America Graduate Student Award National Competition, Soil & Water Management & Conservation Division. Houston, TX, Oct. 6, 2008  First Place, Graduate Oral Competition, Soils Division. Southern Assoc. of Agricultural Scientists. Dallas, TX, Feb. 5, 2008  First Place, Graduate Oral Competition, Soils Division. ASA, Southern Branch. Mobile, AL, Feb. 6, 2007

59. Approved Grants $2,529, International Scholars Program, “Professional Collaboration between Auburn University and the Pan- American Agricultural School”, Honduras, 9/08 $1,149,000, Transportation Enhancement Program, “Wire Road Bicycle Facilities” 11/07 $10,000, SARE (Sustainable Agriculture Research & Education) Graduate Student Grant, “Organic mulches and high residue no-till for collard production in Alabama” 8/05 $3,500, Peace Corps Agricultural Extension Partnership Grant, “Community greenhouses and rural water systems” 9/00

60. Summary PhD Soil Science 2.5 yrs experience in int’l agricultural development Soil C cycling/sequestration Conservation agriculture English, Spanish & others U.S. citizen

61. Summary Proven publication record Successful grant writing Award-winning communication skills Team management Media relations Self-motivated Resourceful

62. Thank you www.auburn.edu/~mulvamj