Effect of fungus chaff on soil microbe population and enzyme activity of three crop soils

Application of fungus chaff is an important measure improving soil healthy and plant growth. A filed experiment was conducted to investigate the effects of fungus chaff of vinegar residue incorporation on the population of soil microorganism, soil microbial biomass carbon, soil microbial biomass nitrogen and enzyme activity in three crops (maize, sorghum and waxy maize) soil at different growth stages. The experiment contained six treatments, three crops not treated and treated with 25 000 kg·hm2 of fungus chaff. The results showed that the incorporation of fungus chaff significantly increased bacteria, actinomyces and fungi population in the rhizosphere soil layer. The number of soil bacteria increased by 32%54% for the three crops after fungus chaff application throughout the growth period. At maturity, actinomyces population significantly increased, especially in maize rhizosphere soil layer where there was the largest increment of 101%. The trend in fungi population increased at jointing and heading stages after decreasing at maturity stage. The use of fungus chaff in rhizosphere soil increased the activities of enzymes (urease, catalase and invertase). Soil urease activity under sorghum, corn and waxy corn increased with 239%, 189%, and 184%, respectively. Soil catalase activity was highest at heading stage, with a maximum increment of 40%. Three crops showed different trends in soil invertase activity at each stage. The activity of soil invertase under maize was not significantly different among growth stages, with increment of 38%, 28% and 48% respectively at jointing, heading and mature stages. Soil microbial biomass carbon and nitrogen increased in all the crops after fungus chaff application. The increase in soil microbial carbon content was 58.10–407.67 mg.kg^-1 and that in microbial nitrogen content was 11.98–27.55 mg.kg^-1 across the growth periods of the three crops. This implied that the application of fungus chaff could be used to boost the population of soil microorganisms and enhance soil microbial biomass carbon and nitrogen, and enzyme activity under the three crop types. This in turn enhanced crop yield and made soil productivity more sustainable. It was therefore recommended to apply fungus chaff of vinegar residues to protect and improve future environmental conditions.