The effects of nitrogen fertilization on N2O emissions from a rubber plantation

Abstract

To gain the effects of N fertilizer applications on N2O emissions and local climate change in fertilized rubber (Hevea brasiliensis) plantations in the tropics, we measured N2O fluxes from fertilized (75 kg N ha−1 yr−1) and unfertilized rubber plantations at Xishuangbanna in southwest China over a 2-year period. The N2O emissions from the fertilized and unfertilized plots were 4.0 and 2.5 kg N ha−1 yr−1, respectively, and the N2O emission factor was 1.96%. Soil moisture, soil temperature, and the area weighted mean ammoniacal nitrogen (NH4+-N) content controlled the variations in N2O flux from the fertilized and unfertilized rubber plantations. NH4+-N did not influence temporal changes in N2O emissions from the trench, slope, or terrace plots, but controlled spatial variations in N2O emissions among the treatments. On a unit area basis, the 100-year carbon dioxide equivalence of the fertilized rubber plantation N2O offsets 5.8% and 31.5% of carbon sink of the rubber plantation and local tropical rainforest, respectively. When entire land area in Xishuangbanna is considered, N2O emissions from fertilized rubber plantations offset 17.1% of the tropical rainforest’s carbon sink. The results show that if tropical rainforests are converted to fertilized rubber plantations, regional N2O emissions may enhance local climate warming.

Irrigation and tillage effects on soil nitrous oxide emissions in maize monoculture

“…The increase in total available soil nitrogen content (ammonium and nitrate) after N fertilizer applications had an impact on soil N 2 O fluxes in both irrigation systems, as it is demonstrated in a relationship shown (Figure 5b). This relationship agrees with other studies (Hoben, Gehl, Millar, Grace, & Robertson, 2011;McSwiney & Robertson, 2005;Zhou et al, 2016) which pointed out the key role of N fertilizer applications on the N 2 O emitted from the soil (Dobbie & Smith, 2003;Vallejo, García-Torres, Diez, Arce, & Lopez-Fernandez, 2005). Moreover, the soil N 2 O flux peaks observed during the top dressing application were related not only with the high N fertilizer rates applied (200 kg N ha −1 ) but also with the high soil temperatures measured, similar to the observations reported by other authors (Dobbie & Smith, 2001;Zhou et al, 2016).…”

Nitrogen‐Related Constraints of Carbon Uptake by Large‐Scale Forest Expansion: Simulation Study for Climate Change and Management Scenarios

“…The effect of N inputs on soil processes is often neglected and only the stimulating effect on plant growth is assessed (e.g., Thomas et al, ). Zhou et al () found a range of 5.8%–31.5% offset of C sequestration by N 2 O emissions for rubber plantations replacing tropical rain forests, which is similar to the range found in this study by applying lower and upper limits for the N 2 O EF. Hence, fertilizer application is a method to trigger for instance boreal expansion of forests that would otherwise be hampered by N limitation; however, the gain in C sequestration can be offset to a large part by emitted N 2 O.…”

Soil greenhouse gas emissions from inorganic fertilizers and recycled oil palm waste products from Indonesian oil palm plantations

“…During this period, the share of N 2 O emissions from the different organic amendments accounted for 34%–51% of annual total cumulative N 2 O emissions (Figure ). Lou and Nair () reviewed that N 2 O emissions were higher at the starting of the decomposition process (He et al, ) due to the availability of labile organic C and higher microbial metabolism activity which serves as an energy and electron source for denitrifiers (Zhou et al, ).…”