NOVELTY - Antagonists comprises Bacillus amyloliquefaciens strain XZ-173 (CGMCC 4160). The bacterial strain XZ-173 has main biological characteristics comprise Gram farbung of G+, rod-shaped cell, catalase is positive, amylolysis is negative, Voges-Proskauer (VP) reaction is negative, methyl red experiment is positive, gelatin hydrolysis is positive, nitrate reduction is positive, and indole test is negative.    USE - Antagonists used for preparing microorganism organic fertilizer for preventing tomato Ralstonia solanacearum or knot nematode (claimed).    ADVANTAGE - The organic fertilizer when added into soil can make antagonists fast breed for forming heterotic group in soil, so that prevention ratio for tomato R. solanacearum is more than 70%, and can reduce more than 80% numbers of knot nematodes in knot nematode diseased soil.    DETAILED DESCRIPTION - Antagonists comprises Bacillus amyloliquefaciens strain XZ-173 (CGMCC 4160). The bacterial strain XZ-173 has main biological characteristics comprise Gram farbung of G+, rod-shaped cell, catalase is positive, amylolysis is negative, Voges-Proskauer (VP) reaction is negative, methyl red experiment is positive, gelatin hydrolysis is positive, nitrate reduction is positive, and indole test is negative. It uses citrate and tartrate for generating ammonia, and fermented dextrose for generating acid and gas. It further uses fermented xylitol, L-arabinose, mannose, cane sugar, and fructose to generate acid. An INDEPENDENT CLAIM is included for manufacture of microorganism organic fertilizer by inoculating antagonists XZ-173 into improved beef extract liquid culture medium for processing fermentation at pH of 7-7.2, cultivating temperature at 30-35 degrees C, and stirring speed of 170 revolutions per minute; forming germ in fermentation middle back period to obtain antagonists liquid containing bacterium or germ at greater than or equal to 1x 1010 cfu/ml; processing solid fermentation to mixture formed by antagonists XZ-173, which is decaying pig manure with rapeseed meal microorganism zymolyte; adding 50 l antagonists liquid per ton solid organic material; turning once during solid fermentation process for each day, so that solid fermentation temperature does not exceed 50 degrees C; finishing after fermenting for 5 days so that content of antagonists is more than 2x 107 cfu/ml; obtaining microorganism organic fertilizer containing antagonists XZ-173; evaporating water content of microorganism organic fertilizer at less than or equal to 60 degrees C until water content is lower than 30%; and packaging product, i.e. microorganism organic fertilizer.