روند تولید 2CO و تغییر کربن بیومس میکروبی در خاک‌های تیمار شده با کود اوره و مرغی

The addition of organic and inorganic substrates to calcareous soils low in organic matter and nitrogen contents may change soil microbial biomass and activity. In order to investigate the effect of chemical and organic fertilizers on soil CO2 production and microbial biomass C, a field experiment was conducted under maize cultivation. The experimental design was split-plot arranged in randomized complete blocks with 7 treatments including 3.8, 7.6 and 11.5 ton ha-1 broiler litter and 100, 200 and 300 kg nitrogen ha-1 from urea and a control with 4 replications. The results showed that fertilizer, manure and sampling day had a significant effect (P<0.05) on soil CO2 fluxes. Mean soil CO2 emissions increased from 21.8 g C m-2 soil in control treatments to 24.1 in the second level of broiler litter. Furthermore, the CO2 fluxes in broiler litter treatments were significantly greater than those in urea-treated plots. Similar to CO2 fluxes, the amount of soil microbial biomass C was also affected significantly (P<0.05) by fertilizer and manure applications. Soil microbial biomass C was 28% higher in broiler litter-amended plots than that in urea-amended plots. In contrast, the microbial metabolic quotient (qCO2) in urea-treated soils was 10% higher than that in broiler litter-treated soils. In conclusion, broiler litter and urea fertilizer improved biological properties in this calcareous soil, but broiler litter, especially the highest litter loading, was more effective than urea fertilizer.