Figure 2

Temporal changes in the CO2 emission rate at the (a) Lusaka and (b) Kabwe sites. Different shapes represent the different fertilizer treatments. The levels of significance at the top of the panels were based on mixed model results for repeated measurements. Error bars represent the standard deviation of the mean (n = 3). CF: chemical fertilizer treatment, CM: cattle manure treatment, PM: poultry manure treatment, MR: maize residue treatment, and NF: no fertilizer treatment.