CH4, CO2 and N2O emissions from grasslands and bovine excreta in two intensive tropical dairy production systems

The production of beef and milk has a significant impact on climate change, as these activities are responsible for a large proportion of the greenhouse gases emitted in agriculture. We used the static closed chamber technique to measure the rate of CH 4 -C, N 2 O-N and CO 2 -C emissions from pastures (102 days) and bovine excretions (27 days) in an intensive pasture monoculture (PM) and an intensive silvopastoral system (ISS) in the Cauca Valley of Colombia. Mean soil CO 2 -C (mg m 2 h −1 ), CH 4 -C and N 2 O-N emissions (μg m −2 h −1 ) were 236.7 versus 113.4; 46.7 versus 1.01 and 344.7 versus 40.1 for the PM and ISS, respectively. The accumulated flows for PM and ISS during the evaluation period were 751.6 and 424.3; 4.39 and − 0.41; and 12.75 and 1.55 (kg ha −1 ) for CO 2 -C, CH 4 -C and N 2 O-N, respectively. Regarding manure, the PM had lower CO 2 -C and CH 4 -C emissions (498.6 vs. 981.2 mg m −2 h −1 , and 1.9 vs. 4.7 μg m 2 h −1 ; p > 0.05), and higher N 2 O-N emissions (2967.3 vs. 1179.8 μg m −2 h −1 ; p = 0.02) than the ISS, respectively. For the urine patches, the ISS emitted only 47.9, 2.2 and 11.6% of the CO 2 -C, CH 4 -C and N 2 O-N emissions observed in the PM, respectively. Moreover, comparing both systems with a forest, CH 4 -C and N 2 O-N emissions from the ISS were not different ( p > 0.05), but the PM presented higher emissions for the three gases ( p