Nitrous oxide emissions from wetland soil amended with two types of cattle manure

Purpose The implications of increased applications ofhigh quality cattle manure to agricultural systems in Africaon N2O emissions are still only partially understood.Methods A field experiment was carried out in a wetlandin central Zimbabwe to determine the effects of cattlemanure quality on emissions of N2O during the growingseasons of rape and tomato crops. The static chamber andgas chromatography techniques were used to capture andmeasure fluxes of N2O.Results The substitution of low N by high N manuresignificantly increased N2O fluxes and total N lost throughN2O emission. Emissions of N2O increase with increasingcontent of N in applied manure.Conclusions Given that N2O in agricultural soil is producedpredominantly through the microbial transformationsof inorganic N, the potential of a soil to emit N2Oincreases with the increasing availability of N and consequentlythe N content in applied manure. The applicationsof lower rate of high and low N manures werefollowed by lower emissions of N2O, a result that isfavorable to the objective of lowering the contribution ofagricultural sources to the global greenhouse gas emissions.The loss of N in emissions of N2O expressed perunit mass of harvested dry matter yield decreases withincreasing manure application, dry matter yield and Nuptake. Improved agronomic practices for increased cropproductivity can be used as a mitigation factor forreducing the contribution of agriculture in the globalemissions of N2O.

کلیدواژه ها:

Agriculture GHGs Wetlands