Soil bacteria Department of Primary Industries（土壤细菌的主要产业）.pdfVIP

Soil bacteria Bacteria are some of the smallest and most abundant are all examples of free-living, nitrogen-fixing microbes in the soil. In a single gram of soil, there bacteria, often associated with non-legumes. To date, can be billions of bacteria. There are an estimated inoculating the soil with these organisms has not 60,000 different bacteria species, most which have proved an effective means of increasing nitrogen yet to be even named, and each has its own particular fixation for non-legume crops. roles and capabilities. Most live in the top 10cm of Disease suppressors soil where organic matter is present. Bacillus megaterium is an example of a bacterium Characteristics of bacteria that has been used on some crops to suppress the Some bacteria species are very fragile and can be disease-causing fungus Rhizoctonia solani . killed by slight changes in the soil environment. Pseudomonas fluorescens may also be useful against this disease. Bacillus subtilis has been used to Other species are extremely tough, able to withstand severe heat, cold or drying. Some can lie dormant for suppress seedling blight of sunflowers, caused by Alternaria helianthi . decades waiting for favourable conditions. Others can extract nitrogen directly from the air or break down A number of bacteria have been commercialised some toxic substances. worldwide for disease suppression. However, Populations of microbes can boom or bust in the suppression is often specific to