Abstract

Conservation tillage management can improve soil moisture and reduce or increase soil CO2 emission. Soil CO2 flux rate, soil moisture, and the relationship between soil respiration and temperature on North China Plain throughout a 3-year period was determined. Tillage systems were rotary tillage without crop residues (CT), rotary tillage with crop residues incorporated into the soil in winter, and no-tillage with crop residues used as mulch in summer (TW), and rotary tillage with crop residues incorporated into the soil in summer and no-tillage with crop residues used as mulch in winter (TS). Soil respiration was measured with a LI-8100 and the gravimetric method was used to identify soil water content. Soil temperature at 5 cm depth also was measured directly by Li- 8100 through a temperature sensing probe during the CO2 measurement time. The crops were winter wheat (Triticum aestivum L) and summer maize (Zea mays L). During the wheat and maize growing period, TS reduced CO2 emission when compared with CT and TW. For the first two years of this study, CT and TW had higher soil water content when compared with TS. Thus, this study suggests that conservation tillage can be useful for North China plain farmers; however, TW emitted CO2 at the highest rate level, therefore further research is needed on long term effects of those three tillage practices on respiration rate and soil moisture in that area.

Key words: Crop residue, tillage, CO2, soil water content, soil respiration, North China plain.