Comparison of Soil Respiration in Typical Conventional and New Alternative Cereal Cropping Systems on the North China Plain
Figure 2
CO2 emissions of different cropping systems.
Con.W/M, Opt.W/M, W/M-M, W/S-M and M represent conventional winter wheat–summer maize in one year, optimized winter wheat–summer maize in one year, winter wheat–summer maize (or summer soybean) –spring maize three harvests in two years and single spring maize system in one year; W, M1, M2, S and F represent winter wheat, summer maize, spring maize, soybean and fallow.