A New Operation for Producing Disease-Suppressive Compost from Grass Clippings

Abstract

This study evaluated the use of grass clippings discharged from golf courses as the raw material for production of a suppressive compost to control Rhizoctonia large-patch disease in mascarene grass. Bacillus subtilis N4, a mesophilic bacterium with suppressive effects on the pathogenic fungusRhizoctonia solani AG2-2, was used as an inoculum in a procedure developed with the aim of controlling composting temperatures and inoculation timing. The population density of mesophilic bacteria in the raw material was reduced to around 5 log10 CFU/g (dry weight) of composting material in the self-heating reaction at the initial stage of composting by maintaining a temperature of 80°C for 1 day. The inoculum was applied immediately, and the composting material was maintained at 40°C for 3 days. This served both to highly concentrate the suppressive bacterium and to achieve sporulation. The temperature was then raised to 60°C and maintained, enabling hygienic, high-speed composting while maintaining the population density of the suppressive bacterium as high as 8 log10 CFU/g (dry weight) in the compost. The suppressiveness of compost made in this way was confirmed in a turf grass disease prevention assay.

Predominant Culturable Bacillus Species in Japanese Arable Soils and Their Potential as Biocontrol Agents

“…1b). Nakasaki et al 19) found that compost from grass clippings suppressed Rhizoctonia patch disease on the inoculation of B. subtilis N4. This study demonstrated that the suppressive effect of PMC was enhanced by the inoculation of B. megaterium N2S6.…”

“…Recently, Felske et al 6,7) reported that Bacillus species, especially B. benzoevorans, constitute a majority of the bacteria in Dutch soil using culture-independent and culture-dependent methods. It is known that Bacillus species produce at least 66 different antibiotics 13) and certain Bacillus strains are antagonistic to plant pathogenic fungi and bacteria and thereby function as a biocontrol agent 3,4,9,19,24,27) .…”

High Culturability of Bacteria in Commercially Available Personal Composters for Fed-batch Treatment of Household Biowaste

“…The available information on viable counts of microorganisms in compost differs greatly among studies. For example, numbers of viable bacteria detected as CFU g -1 (dry wt) of compost in previous studies had an order of magnitude of 10 9 in continuously thermophilic composting processes 19) , 10 8 in thermophilic stages of composting 16) , 10 9 in municipal waste compost 7) and 10 6 to 10 9 in a field-scale composter 17) . Michel et al 15) found much greater population densities of thermophilic bacteria (10 11 CFU g -1 dry wt) in a temperature-controlled laboratory-scale composting process.…”

Rhizosphere-enriched microbes as a pool to design synthetic communities for reproducible beneficial outputs

“…Several studies using cultivation-based techniques allowed the identification of antagonistic bacteria and fungi that when proliferating in the rhizosphere promoted plant growth and protected host plants from pathogens. In several cases, such isolated strains have been used to fortify composts and improve their consistency to control diseases 57,58 . Herein, we extend on our previous work by evaluating the antifungal and growth promotion potential of the bacteria enriched in the rhizosphere of tomato plants 26 , and by designing synthetic communities we aim to understand how the composition of microbial consortia can explain the enhanced growth and protection observed against the fungal wilt pathogens of tomato.…”