Effects of conservation tillage on soil respiration and microorganism amount in maize rhizosphere soil in Loess Plateau

The study was executed to analyze the influence of no tillage and residue retention on soil respiration and microorganism of maize rhizosphere soil in Qingyang Loess plateau after 10 years implementation of conservation tillage. Soil respiration was measured using LICOR640009, soil Respiration Chamber completed with Infrared Gas Analyzer under 10years conservation tillage, and microorganism amount of maize rhizosphere soil was measured by the method of dilution plate counting. The results showed that no tillage and residue retention significantly decreased the soil respiration rates of maize anthesis by 8.3% and 7.8% as well as harvesting period by 15.5% and 13.6%. The top 10 cm ground temperature and the soil respiration rates were the same and the top 10 cm ground temperature under traditional tillage treatment was the highest. The amount of bacteria, fungi and actinomycosis under no tillage and residue retention were higher than that in conventional tillage treatment and the ratio between three kinds microbe was not changed. Soil respiration rate had negative correlation with the amount of bacteria, fungi and actinomycosis, which was not significant (P0.05). Many factors can influence the soil respiration rate, and the soil temperature was the main factor for soil respiration rate.