Impacts of fertilizers and mushroom residue on CO2 emissions from soils under rice-wheat rotation in Chengdu Plain

摘要

The static chamber/gas chromatography method is adopted to observe the annual CO2 emissions of farmlands which have received different treatments of “returning mushroom residues to farmlands” in the rice-wheat rotational area in Chengdu Plain. The results showed that: (1) the CO2 emission amount from mushroom residues application in the wheat season is significantly lower than those from contrast treatment and from straws application treatment, while in the rice season, the CO2 emission amounts from all contrast treatment are significantly lower than those from mushroom residues application teatments and from straws application. (2) The CO2 emissions of farmlands receiving all treatments all change significantly over seasons. At the wheat seedling stage and tillering stage, the variations of CO2 emission flux are small. As the air temperature rises and the wheat grows vigorously, the CO2 emission amount increases rapidly, reaching peak values at the boot stage and the mature stage; in the paddy fields, the CO2 emission flux gradually increases after fertilization, and reaches peak values at the early tillering stage and at the jointing stage during water drainage and field drying. (3) There is significant correlation between the CO2 emission flux of farmland and the crop biomass, indicating that the growth of crops is a crucial factor that influences the seasonal variation of CO2 emission in farmlands. (4) The researchers hold that the application scheme T4 for mushroom residues to farmland is the best scheme.