A new operation for producing disease-suppressive compost from grass clippings

Area of Science:

• Agricultural Science
• Microbiology
• Plant Pathology

Background:

• Rhizoctonia large-patch disease poses a significant threat to mascarene grass turf.
• Effective and sustainable disease management strategies are crucial for golf course maintenance.
• Utilizing organic waste materials for compost production offers environmental and economic benefits.

Purpose of the Study:

• To evaluate golf course grass clippings as a raw material for suppressive compost production.
• To develop a composting procedure using Bacillus subtilis N4 to control Rhizoctonia large-patch disease.
• To optimize composting conditions for high populations of the suppressive bacterium.

Main Methods:

• Grass clippings were used as the composting substrate.
• Bacillus subtilis N4 was introduced as an inoculum at a specific stage.
• Composting temperatures were controlled: 80°C for 1 day, then 40°C for 3 days, followed by 60°C.
• Population density of Bacillus subtilis N4 was monitored throughout the process.

Main Results:

• A composting procedure was established using grass clippings and Bacillus subtilis N4.
• Controlled temperatures ensured initial reduction of mesophilic bacteria and subsequent high populations of the inoculum.
• The final compost demonstrated suppressiveness against Rhizoctonia solani AG2-2 in a disease prevention assay.

Conclusions:

• Golf course grass clippings can be effectively transformed into a suppressive compost.
• The developed composting method successfully produced a high concentration of Bacillus subtilis N4.
• The resulting compost is a viable biological control agent for Rhizoctonia large-patch disease in mascarene grass.