Effects of Straw Bio-reactor on Microorganism Population and Soil Enzyme Activity in the Watermelon Replant Soil

Abstract:

Corn straw bio-reactors were constructed in 2-, 4-, and 8-year replant soils grown with watermelon, while the 2-, 4-, and 8-year replant soils (without bio-reactors) were used as controls, respectively. The soil nutrient contents, pH, microorganism quantities, and soil enzyme activities were determined to evaluate the effectiveness of corn straw reactor’s improvement on soil health. Results showed that the soil organic matter content, microorganism quantities, and soil enzyme activities were increased significantly after 1- or 2- yearcorn straw bio-reactor treatments. In the 8-year replant soil treated with 2-year corn straw bio-reactors, the organic matter content reached 2.41%, the number of bacteria was 1.65 × 108 CFU/g, the actinomycetes was 3.12 × 106 CFU/g, the fungi was 0.5 × 105 CFU/g, and the abuscular mycorrhizal fungal spore density was 57/50 mL soil, which were 2.2, 5, 1.44, 1.36, and 3.2 times of their respective controls; while the polyphenol oxidase and sucrose invertase activities were 1.25 and 2.13 times of their controls, respectively. It was suggested that the corn straw bio-reactor be benefitial to rehabilitate replant soil.