Greenhouse Gas Fluxes in an Eastern Corn Belt Soil: Weather, Nitrogen Source, and Rotation

Abstract

Relative contributions of diverse, managed ecosystems to greenhouse gases are not completely documented. This study was conducted to estimate soil surface fluxes of carbon dioxide (CO(2)), methane (CH(4)), and nitrous oxide (N(2)O) as affected by management practices and weather. Gas fluxes were measured by vented, static chambers in Drummer and Raub soil series during two growing seasons. Treatments evaluated were corn cropped continuously (CC) or in rotation with soybean (CS) and fertilized with in-season urea-ammonium nitrate (UAN) or liquid swine manure applied in the spring (SM) or fall (FM). Soybean (SC) rotated with CS and restored prairie grass (PG) were also included. The CO(2) fluxes correlated (P <or= 0.001) with soil temperature (rho: 0.74) and accumulated rainfall 120 h before sampling (rho: 0.53); N(2)O fluxes correlated with soil temperature (rho: 0.34). Seasonal CO(2)-C emissions were not different across treatments (4.4 Mg ha(-1) yr(-1)) but differed between years. Manured soils were net seasonal CH(4)-C emitters (0.159-0.329 kg ha(-1) yr(-1)), whereas CSUAN and CCUAN exhibited CH(4)-C uptake (-0.128 and -0.177 kg ha(-1) yr(-1), respectively). Treatments significantly influenced seasonal N(2)O-N emissions (P < 0.001) and ranged from <1.0 kg ha(-)(1) yr(-1) in PG and SC to between 3 and 5 kg ha(-1) yr(-1) in CCFM and CSUAN and >8 kg ha(-1) yr(-1) in CCSM; differences were driven by pulse emissions after N fertilization in concurrence with major rainfall events. These results suggest fall manure application, corn-soybean rotation, and restoration of prairies may diminish N(2)O emissions and hence contribute to global warming mitigation.

In-Field Management Practices for Mitigating Soil CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; Fluxes under Corn (&lt;i&gt;Zea mays&lt;/i&gt;) Production System in Middle Tennessee

“…The generally low values and net uptake of CH 4 presented in our study were consistent with those reported for other cornfields [7] [14] [21]. Soil CH 4 is often formed under anaerobic conditions by methanogens [18].…”

“…Similar results were also revealed in some other cornfields studies [7] [14] [30]. However, several studies reported that no-tillage, alternative fertilizer sources (manure) and soil management (biochar application) can significantly alter soil CH 4 flux [18]- [21]. Different results from these studies are probably due to the differences in soil texture or climate.…”

“…Methane is produced when organic C decomposition in oxygen-deprived conditions, notably from crop grown under flooded conditions [17]. The processes of CH 4 flux, including production, oxidation, and transport into the atmosphere are influenced by agricultural practices [18]- [21]. For instance, no-tillage reduces CH 4 emissions from paddy soils because soil conditions under no-tillage are more oxidative than those of conventional tillage [19] [20].…”

“…For instance, no-tillage reduces CH 4 emissions from paddy soils because soil conditions under no-tillage are more oxidative than those of conventional tillage [19] [20]. Applications of swine manure in a continuous corn cropping system result in net CH 4 emission, whereas similar plots receiving urea fertilizer are sinks of CH 4 in the eastern United States [21]. Similarly, biochar applications were reported to decrease emissions of CH 4 in many croplands [18].…”

Technical options for the mitigation of direct methane and nitrous oxide emissions from livestock: a review

“…Wet soils tend to promote N 2 O emissions, and therefore application timing (e.g. avoiding application before a rain event) can be important (Hernandez-Ramirez et al, 2009;Smith and Owens, 2010;Meada et al, 2011).…”