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  • Cover crop field trial.

  • Roller crimper in a no-till system with sunn hemp cover crop.

  • Learning how to use the cover crop calculator.

  • Cover crops (left to right) cowpea, woolly pod vetch, sunn hemp with a black oat border.

  • Talking about cover crops at the Urban Garden Center.



1) Wang, K.-H., J. Bloese, J. Uyeda, J. Silva, H. Lutgen, K. Tavares, R. Manandhar. 2023-2028. Regenerating Soil Health through Shelterbelt Planting, Sheet Mulching and Tree Mulch Plant-Available Nitrogen Calculator. NRCS OnFarm Trial. NR233A750011G011

2) Wang, K.-H., J. Uyeda, J. Silva, D. Elliot, T. Radovich. 2022. Western Cover Crop Council Outreach Grant. U.S. USDA NIFA 2018-38640-28418 through Western SARE (WESP 19-01).

3) Wang, K.-H., K. Lawrence, B. S. Sipes, E. Sikora, Z. Cheng, R. Myers, R. Manandhar, J. Uyeda, S. Marahatta. 2021-2024. Organic sweetpotato IPM and soil health management for small- and mid-size farms. NIFA OREI (HAW09705-G).

4) Wang, K-H., J. Silva, and J. Uyeda. 2021-2023. Cover crop mix for orchard or trellis fruit and vegetable crops: Better soil health and weed management in Hawaii. NRCS CIG PIA (NR2192510002G002).

5) Wang, K.-H., J. Silva, and J. Hawkins. 2019-2021. Finding new friends for sunn hemp to revitalize degraded soil in the tropic. NRCS CIG PIA (NR1992510002G001).

6) Waisen, P. and K.-H. Wang. 2017-2019. “Cover Crop 5-in 1 Approach” for nematode management using mustard and oil radish. WSARE $25,000.

7) Wang, K.-H., Archana Pant, Jari Sugano, and Jensen Uyeda. 2015-2018. Improving water use efficiency through no-till cover cropping and solarization. NRCS CIG (Hawaii).

8) Wang, K.-H., T. Radovich, A. Pant, N. Andrew, N. Hue, J. Sugano and J. Uyeda. 2014-2017. Promoting the use of cover crop calculator for the tropics as nitrogen management tool and the use of cover crops for soil health management guideline. NRCS CIG (National).

9) Wang, K.-H., A. Pant, T. Radovich, J. Sugano, C. Tamaru, B. Fox, J. Uyeda, S. Chiang, C. Chan-Halbrandt. 2013-2016. Center of Rural Agriculture Training for Entrepreneurship (CRATE) for the Pacific. NIFA AFRI AE&RC

10) Wang, K.-H et al. 2013-2015. The influence of cover crops and tillage on soil quality, greenhouse gas emissions, pest community dynamics, and economics of fields transitioning to organic farming. NIFA ORG.

11) Wang, K.-H., L. Kaufman, B.S. Sipes, T. Radovich, and J. Sugano. 2010-2012. An innovative cover cropping system for organic cucurbit growers in Hawaii: From nematode and pickleworm management, improvement of pollinator habitat to soil conservation. NRCS CIG.

12) Wang, K.-H., C.R.R. Hooks, B.S. Sipes, J. Sugano, and A. Arakaki. 2010-2012. Using conservation tillage and cover crop mixtures to enhance natural enemies of nematode pests. TSTAR.

Selected Publications

To access PDF files of my publications, please visit ResearchGate at

  • Wang, K.-H. P. Waisen, R. Paudel, G. Chen, S.L.F. Meyer and C.R.R. Hooks. 2022. Effects of plasticulture and conservation tillage on nematode assemblage and their relationships with nitrous oxide emission following a winter cover cropping and vegetable production system. Horticulturae 8: 728.
  • Marquez, J., R. Paudel, B. S. Sipes, and Koon-Hui Wang. 2022. Successional effects of no-till cover cropping with black oat ( Avena olariza) vs. soil solarization on soil health in a tropical Oxisol.  Horticulturae 8: 527 (
  • Wang, K.-H., P. Waisen, A. W. Leslie, R. Paudel, S.L.F. Meyer and C.R.R. Hooks. 2022. Relationships between soil tillage systems, nematode communities and weed seed predation. Horticulturae 8: 425.
  • Paudel, R., P. Waisen, and K.-H. Wang. 2021. Exploiting the innate potential of sorghum/sorghum–sudangrass cover crops to improve soil microbial profile that can lead to suppression of plant-parasitic nematodes. MDPI-Microorganisms 9:1831
  • Manandhar, R., K.-H. Wang, C. R.R. Hooks, and M. Wright. 2017. Effects of strip-tilled cover cropping on the population density of thrips and predatory insects in a cucurbit agroecosystem. Journal of Asia-Pacific Entomology 192_R1.
  • Kokalis-Burelle, N., R. McSorley, K.-H. Wang, S. Saha, R. McGovern. 2017. Rhizosphere microorganisms affected by soil solarization and cover cropping in Capsicum annuum and Phaseolus lunatus agroecosystems. Applied Soil Ecology 119: 64-71.
  • Leslie, A., K.-H. Wang, S. Meyer, C. R.R. 2017. Hooks. Influence of cover crops on arthropods, free-living nematodes, and yield in a succeeding no-till soybean crop. Applied Soil Ecology 117-118: 21-31.
  • Quintanilla-Tornel, M.A., K.-H. Wang, J. Tavares, C.R.R. Hooks. 2016. Effects of mulching on above and below ground pests and beneficials in a green onion agroecosystem. Agriculture, Ecosystems, & Environment 224: 75-85.
  • Hinds, J., K.-H. Wang, and C. R.R. Hooks. 2015. Growth and yield of zucchini squash (Cucurbita pepo L.) as influenced by a sunn hemp living mulch. Biological Agriculture & Horticulture. 13 pp. DOI: 10.1080/01448765.2015.1017736.
  • Wang, K.-H., T. Radovich, A. Pant, and Z. Cheng. 2014. Integration of cover crops and vermicompost tea for soil and plant health management in a short-term vegetable cropping system. Applied Soil Ecology 82: 26-37. DOI: 10.1016/j.apsoil.2014.05.003
  • Hinds, J., K.-H. Wang, S. P. Marahatta, S. L.F. Meyer, and C. R.R. Hooks. 2013. Investigating the influence of sunn hemp cover cropping and organic fertilizer on the nematode community in a zucchini cropping system. Journal of Nematology 45: 265-271.
  • Marahatta, S.P., K.-H. Wang, B.S. Sipes, and C.R.R. Hooks. 2012. Effects of Tagetes patula on active and inactive stages of root-knot nematodes. Journal of Nematology 44: 26-30.
  • Marahatta, S. P., K.-H. Wang, B.S. Sipes, and C.R.R. Hooks. 2012. Effects of the integration of sunn hemp and soil solarization on plant-parasitic and free-living nematodes. Journal of Nematology 44: 72-79.
  • Marahatta, S. P., K.-H. Wang, B.S. Sipes, and C.R.R. Hooks. 2012. Effects of Crotalaria juncea on anhydrobiotic state of Rotylenchulus reniformis. Nematropica 42: 34-40.
  • Hooks,C. R.R., K.-H. Wang, S.L.F. Meyer, M. Lekveishvili, J. Hinds, E. Zobel, A. Rosario-Lebron, and M. Lee-Bullock. 2011. Impact of no-till cover cropping of Italian ryegrass on above and below ground faunal communities inhabiting a soybean field with special emphasis on soybean cyst nematodes. Journal of Nematology 43: 166-175.
  • Wang, K.-H., C.R.R. Hooks, and S.P. Marahatta. 2011. Can using a strip-tilled living mulch system enhance organisms higher up in the soil food web hierarchy? Applied Soil Ecology 49:107-117(doi:10.1016/j.apsoil.2011.06.008 ).
  • Hooks, C.R.R., K.-H. Wang, A. Ploeg, R. McSorley. 2010. Using marigold (Tagetes spp.) as a cover crop to protect crops from plant-parasitic nematodes. Applied Soil Ecology 46: 307-320.
  • Wang, K.-H., B.S. Sipes, and C.R.R. Hooks. 2011. Sunn hemp cover cropping and solarization as alternatives to soil fumigants for pineapple production. Acta Hort (ISHS) 902: 221-232.
  • Marahatta, S. P., K.-H. Wang, B.S. Sipes, and C.R.R. Hooks. 2010. Strip-till cover cropping for managing nematodes, soil microarthropods and weeds in a bitter melon agroecosystem. Journal of Nematology 42: 111-119.
  • Wang, K.-H., R. McSorley, R. N.Gallaher, N. Kokalis-Burelle. 2008. Cover crops and organic mulches for nematode, weed, and plant health management. Nematology 10: 231-242.
  • Wang, K.-H., R. McSorley, N. Kokalis-Burelle. 2006. Effects of cover cropping, solarization, and soil fumigation on nematode communities. Plant and Soil 286: 229-243.
  • Wang, K.-H., R. McSorley, A. J. Marshall, and R. N. Gallaher. 2004. Nematode community changes following decomposition of Crotalaria juncea amendment in litterbags. Appl. Soil Ecology 27:31-45.
  • Wang, K.-H., R. McSorley, R. N. Gallaher. 2004. Effect of Crotalaria juncea amendment on squash infected with Meloidogyne incognita. J. Nematol. 36: 290-296.
  • Wang, K.-H., R. McSorley, R. N. Gallaher. 2004. Relationship of soil management history and nutrient status to nematode community structure. Nematropica 34: 83-95.
  • Wang, K.-H., R. McSorley, R. N. Gallaher. 2003. Effect of Crotalaria juncea amendment on nematode communities in soil with different agricultural histories. J. Nematol. 35: 294-301.
  • Wang, K.-H., B. S. Sipes, and D. P. Schmitt. 2003. Intercropping cover crops with pineapple for the management of Rotylenchulus reniformis and Meloidogyne javanica. J Nematol. 35: 30-47.
  • Wang, K.-H., B. S. Sipes, and D. P. Schmitt. 2002. Crotalaria juncea as a cover crop for nematode management: A review. Nematropica 32: 35-57.
  • Wang, K.-H., B. S. Sipes, and D. P. Schmitt. 2003. Suppression of Rotylenchulus reniformis enhanced by Crotalaria juncea amendment in pineapple field soil. Agri. Eco. Environ. 94: 197-203.
  • Wang, K.-H., B. S. Sipes, and D. P. Schmitt. 2002. Management of Rotylenchulus reniformis in pineapple, Ananas comosus, by intercycle cover crops. J. Nematol. 34: 106-114.
  • Wang, K.-H., B. S. Sipes, and D. P. Schmitt. 2001. Suppression of Rotylenchulus reniformis by Crotalaria juncea, Brassica napus, and Tagetes erecta. Nematropica 31(2): 235-249.


Extension Publications at CTAHR




Procedure for sunn hemp strip till cover cropping.

  • 1. Plant sunn hemp in rows for 2-3 months.

  • 2. Cut down alternate rows of sunn hemp.

  • 3. Till in alternate rows of sunn hemp.

  • 4. Transplant cucumber seedlings, trim sunn hemp living mulch.

  • 5. Trim sunn hemp living mulch once a month and use as surface mulch.

  • 6. Sunn hemp is easier mowed by flail mower.

  • 7. Close up of flail mower.

  • 8. Flail mowed sunn hemp residues.

  • 9. Sunn hemp could also be mulched down using roller crimper.


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