Evaluate sorghum and sorghum-sudangrass hybrids as soil builders and microbial enhancer crops in the tropic.

Project Overview

Project Type: Graduate Student
Funds awarded in 2020: $25,000.00
Projected End Date: 08/31/2022
Grant Recipient: University of Hawaii
Region: Western
State: Hawaii
Graduate Student:
Major Professor:
Dr. Koon-Hui Wang
University of Hawaii
Major Professor:
Dr. Amjad Ahmad
University of Hawaii at Manoa
Roshan Paudel
University of Hawaii
Joshua Silva
University of Hawaii at Manoa, College of Tropical Agriculture a
Philip Waisen
University of Hawaii


  • Agronomic: sorghum (sweet), sorghum sudangrass
  • Vegetables: eggplant


  • Crop Production: cover crops, no-till, tissue analysis
  • Education and Training: demonstration, display, extension, on-farm/ranch research
  • Production Systems: agroecosystems
  • Soil Management: organic matter, soil analysis, soil microbiology, soil physics, soil quality/health

    Proposal abstract:

    Cover crops play important roles in maintaining soil health. This project focuses on identifying a cover crop that have additional benefits besides soil erosion control including disease suppression, and water conservation. In particular, I would like to devote my Ph.D. dissertation into evaluating the multi-facet benefits of sorghum and sorghum-sudangrass hybrids (I hear by refer this as SSgH) for their potential in suppressing plant-parasitic nematodes and soil borne fungi, while contributing to increase soil organic matter that will lead to soil moisture retention. This is the first year of my Ph.D. program. Although I am partially funded by other projects of my adviser, I do not have sufficient funding to carry out multiple components of the soil health assays for SSgH. I am proposing to work with researchers, two edible crop extension agents and three local farmers with different farming operations. I aim to evaluate SSgH as a viable tropical cover crop for their 1) soil building and water conservation properties; 2) plant growth enhancement potential following a no-till SSgH cover cropping practice, and 3) ability to enhance beneficial soil microbiome that are associated with various soil health improvement properties. While PI Wang had been demonstrating the great benefits of another tropical cover crop, sunn hemp, for soil health management, this project come in critical now as sunn hemp is suffering from soilborne fusarium disease throughout Hawaii. By collaborating with extension agents, we also will work with a new farmers training program in Hawaii to reach out to wider audience.

    Project objectives from proposal:

    The overall goal of this project is to identify sorghum and sorghum-sudangrass hybrids that are most efficient in tropical climate for suppressing soil-borne pathogens, improving soil water holding properties and enhancing soil microbiome that can contribute to better soil nutrient cycling and ecosystem functioning. Under a no-till cover cropping system, this healthy soil microbiome would not be disturbed and can help to increase soil organic matter faster. These would improve soil aggregates, water infiltration, thus a better water conservation. Specific objectives of this project are:

    1. Evaluate sorghum/sorghum-sudangrass hybrids for soil building and water conservation properties in a no-till farming eggplant agroecosystem (by Paudel, Wang, Silva)
    2. Evaluate eggplant growth and soil-borne disease suppression following no-till planting of different sorghum/sorghum-sudangrass hybrids (by Paudel, Ahmad).
    3. Identify sorghum/sorghum-sudangrass hybrids with distinct microbiome that are associated with good water conservation properties, soil-borne disease suppression and nutrient cycling (by Paudel, Wang, Waisen)

    This project will be carried out over a 2-year period at three locations, one at Poamoho Experiment Station, University of Hawaii, the others at Kahumana Farm, an organic farm advocate for permaculture, and Tolentino Farm, a family farm at Waianae. The best outcome of this study will also be demonstrated at a conventional leafy green farm that is always challenged by soil-borne fungal disease problem (Owen Kaneshiro Farm). Detail of measurable outcomes of each objective are listed in Materials and Methods section below. Field days will be organized by the PI and the collaborative extension agents who are also our co-PIs multiple times a year to update findings to local farmers in Hawaii, in particular to new farmers under GoFarm Hawaii New Farmers training program as well as clients of CTAHR Sustainable and Organic Agriculture Program (SOAP). We aim to provide more incentive for farmers to practice no-till cover cropping in Hawaii.

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.