Sorghum-Sudangrass Hybrids
Sorghum bicolor x S. bicolor var. sudanense

Sudex, Sudax (DeKalb reg brand)

Summer annual grass


  • Biomass/organic matter source (Dry Matter: 8,000-10,000 lbs/ac/yr)
  • Weed suppression
  • Nematode and disease suppression
  • Subsoil loosener
  • Forage
  • Insectary plant

Plant Highlights

  • EXCELLENT for taking up & storing excess N, for increasing organic matter and improving soil structure, for providing erosion control, for quick growth and establishment
  • VERY GOOD for suppressing weeds, for animal grazing (production, nutritional quality & palatability), for providing lasting residue.

Cultural Traits

  • Excellent heat tolerance
  • Excellent drought tolerance
  • Good shade tolerance
  • Good flood tolerance
  • Good tolerance to low fertility
  • pH range 5.5-8.3 (NRCS), prefers 6.0-7.0 (SAN)


Planting depth: 1/2 - 1.5 inches

Seeding Method

  • Drilled: Seed at 35 lb./A (1 bu/A)
  • Broadcast: Seed at 40-50 lb./A (1-1.25 bu/A)

Seed Cost: .21-.66 $/lb

Seed Availability: Readily available


Cultivars commonly recommended by the Hawai`i Natural Resources Conservation Service include: 'DeKalb SX-17+' and 'DeKalb ST-6E' (Sudex, Sudax)


with buckwheat, sesbania, sunn hemp, forage soybeans, cowpeas

Soil Improvements

  • Excellent for loosening subsoil
  • Good at releasing P and K
  • Good at loosening topsoil

Pest Control

  • Very good nematode suppression
  • Very good disease suppression
  • Excellent allelopathic properties (weed)
  • Excellent weed suppression
  • Good for attracting beneficial insects

Management Attributes

  • Good trafficability
  • Rapid establishment and growth ideal for short windows


  • For loosening hardpans, mowing when stalks reach 3 to 4 feet tall increases root mass and forces roots to penetrate deeper into the subsoil.
  • Sow at higher rates for best results as a weed smother crop. Allelopathic compounds secreted by the roots can last for weeks.
  • Plants become woody as they mature and tough residues can pose a management problem. Chopping to decrease residue size will help. Mowing when stalks are 3-4 feet tall keeps growth vegetative and less fibrous.
  • Nitrogen tie-up from residue can occur. To minimize this effect: 1) interplant a legume cover crop, 2) follow up with a legume cover crop, or 3) apply N and leave fallow to give time for residue to decompose.
  • Often sorghum-sudangrass hybrids are used effectively for nematode suppression. Effects vary with cultivars.


Uses in the Pacific Region

No information is available in this database on this topic.

Uses in Hawai`i

The Hawai`i Natural Resources Conservation Service Technical Guide includes Sorghum-Sudangrass hybrids (cv. 'DeKalb SX-17+', 'DeKalb ST-6E'). Their specification describes Sorghum-Sudangrass hybrids as follows:

  • Minimum broadcast seeding rates of 50 lbs. pure live seed/acre;
  • pH range from 5.5-8.3;
  • Approximate growing time 60 days;
  • Approximate dry matter yield 3 tons/acre;
  • Approximate N content 13 lbs./T dry matter;
  • Add 25 lbs. of nitrogen/ton dry matter at plow down;
  • Optimum planting period year round at elevations between 0-1000 ft;
  • Optimum planting period spring/summer at elevations between 0-2000 ft.

'DeKalb SX-17+' and 'DeKalb ST-6E' cultivars are root knot nematode resistant (Robert Joy, NRCS, personal communication).

A. Arakaki, UH Cooperative Extension Service, reports using sudax successfully on Moloka`i in areas with severe nematode problems.

For More Information

UC Davis On-line Cover Crop Index


1998. Managing Cover Crops Profitably, 2nd ed. Sustainable Agriculture Network, National Agricultural Library, Beltsville, USA. pp. 212.

1998. Managing Cover Crops Profitably, 2nd ed. Sustainable Agriculture Network, National Agricultural Library, Beltsville, USA. pp. 212.

USDA Natural Resources Conservation Service, Hawai`i Field Office Technical Guide, Section IV, Code 340 "Cover and Green Manure Crop" May 1992. Pacific Islands Area Field Office Technical Guide (eFOTG) - East Area

Text last updated on 9/23/02.

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These webpages were originally generated under a grant program from Western SARE entitled "Covering New Ground: Tropical Cover Crops for Improving Soil Quality" EW98-012 (1998-2002).