Effect of compost on aflatoxin production from Aspergillus flavus and com yield   Vanlada Sunathapongkuk Chaveevan Leaungvutivirog Udom Pupipar Pitayakon Limtong Prasode Thamakate Siangjeaw Piriyaprin Prachoom Juthawantana and Prawat Tunbuneak   ABSTRACT         Study on the influence of compost on aflatoxin production and corn yield as suwan 3 varieties in Pakchong soil series was conducted at National Corn and Sorghum Research, Nakornrachaseema province during 1991-1994. The experimental plan was randomized complete block design. There were 12 treatments and 3 replications which consisted of appied 0, 4 and 6 ton per rai of compost with 25 kg per rai of chemical fertilizer (16-20-0). Addition and non-inoculated plant pathogen (Aspergillus flavus) in soil and also apploed and without antagonistic microorganisms. The results indicated that application of compost at 4 ton per rai with antagonistic microorganisms and inoculated A. flavus after harvesting corn yield showed the cooperated role to contribute the efficient soil chemical, biological and physical properties. Bacterial actinomycetae and fungal population in soil were increase from 9.32, 8.82 and 5.04 to 10.77, 9.90 and 6.54 log no. per gm of soil. These microorganisms had effect decreasing plant pathogen from 4.63 to 2.08 log no. per gm of soil. Some soil nutrients were increase such as nitrogen content was changed in indicating significantly different from 0.11 to 0.19% comparing without compost application. Phosphorus, potassium, magnesium and calsium were raised from 122.0, 154.7, 206.6 and 2673 to 195.0, 290.7, 262.3 and 3290 ppm respectively. The microelements such as manganese and zinc were changed from 50.6 and 2.1 to 67.3 and 3.4 ppm. The level of siol pH was increase from 5.6 to 6.4 As the increment of soil microbial number had shown highly significantly different and affected to deleted aflatoxin content in soil from 37.7 to 11.9 ppb after applied antagonistic microbes with 4 ton per rai of compost. The distribution of plant disease was reduced which caused to decrease aflatoxin production in corn seed from 145.3 to 81.1 ppb. Percentage of seed-borne disease in corn was also deleted from 70.0 to 20.6% which had implemented soil potential for increasing corn yield from 417.3 to 554.7 kg per rai. In case of non-inoculated A. flavus in soil, after applied compost 4 ton perrai or biological microbes and coorperation had effect increasing soil microbial number less than in inoculated plant pathogen. But there were no signiticant in changed of soil nutrients and cornyield.         Keywords: compost, aflatoxin