Soil respiration and its affecting factors in dry-land maize field under different tillage systems

To explore the effects of different tillage systems on soil reparation during the summer maize crop growing season, the tillage systems included deep tillage (DT), no tillage (NT), rotary tillage (RT) and plow tillage (PT) was designed. The soil respiration, its affecting factors and the relationship of soil respiration rate with soil moisture, soil temperature, soil organic matter, total nitrogen and soil pH was elucidated. The results indicated that soil respiration rate was first increased then decreased during the whole crop period in all kinds of tillage systems. The maximum of soil respiration rate was DT, followed by PT, RT, NT. Soil temperature of PT was the highest, followed by DT, RT, NT from seeding to jointing stage; that of NT was the highest, followed by RT, DT, PT from tasseling to maturity stage. Soil organic matter, and Total nitrogen were gradually increased from planting to flowering stage, those of PT.was higher than those of NT. Soil pH value were significantly different during the growth stages, that of PT was the maximum, followed by RT, NT, DT. Soil moisture and soil temperature were significant correlated with soil respiration (P>0.05). DT and PT were significantly correlated with soil moisture and soil temperature; soil organic matter were negatively correlated with soil respiration rate, and similarly significantly negative correlation was recorded between soil organic matter contents of DT and soil respiration rate. The negative correlations (P>0.05) were recorded between total nitrogen and soil pH value for soil respiration under DT, RT, PT. The study provides a guideline for the complement of soil respiration and emission mechanism, the assessment of regional carbon input and output balance, and the establishment of feasible soil carbon regulation.