Impacts of crop rotational diversity and grazing under integrated crop-livestock system on soil surface greenhouse gas fluxes

Abstract

Integrated crop-livestock (ICL) system is beneficial in enhancing soil organic carbon and nutrient cycling. However, the benefits of the ICL system on mitigation of GHG emissions are poorly understood. Thus, the present study was initiated in 2011 to assess the effect of crop rotation diversity and grazing managed under the ICL system on GHG emissions. The cropping system investigated here included spring wheat grown continuously for five years and a 5-yr crop rotation (spring wheat-cover crops-corn-pea/barley-sunflower). Each phase was present each year. Yearling steers grazed only the pea/barley, corn and cover crops plots in 2016 and 2017. Exclusion areas avoided the grazing in these crops to compare the GHG fluxes under grazed vs. non-grazed areas. The GHG fluxes were measured weekly from all crop phases during the growing season for both years using a static chamber. Cumulative CO 2 and CH 4 fluxes were similar from all crop phases over the study period. However, continuous spring wheat recorded higher cumulative N 2 O fluxes (671 g N ha -1 ) than that under spring wheat in rotation (571 g N ha -1 ). Grazing decreased cumulative CO 2 fluxes (359 kg C ha -1 ) compared to ungrazed (409 kg C ha -1) , however, no effect from grazing on cumulative CH 4 and N 2 O fluxes over the study period were found. The present study shows that grazing and crop rotational diversity affected carbon and nitrogen inputs, which in turn affected soil CO 2 and N 2 O fluxes. Long-term monitoring is needed to evaluate the response of soil GHG emissions to grazing and crop rotation interactions under the ICL system.

Fertilizer timing affects nitrous oxide, carbon dioxide, and ammonia emissions from soil

“…These results are similar to those reported by Abagandura et al. () and Linn and Doran (). The lowest N 2 O emissions (0.165 ± 0.002 g N 2 O‐N ha −1 h −1 ) occurred in the early winter which corresponded to low soil moisture contents (0.234 ± 0.014 cm 3 cm −3 ) and low CO 2 ‐C (285 ± 67 g CO 2 ‐C ha −1 h −1 ), whereas the highest emissions occurred in the early spring when soil moisture and CO 2 emissions were high.…”

“…The correlation analysis between the individual components shows that N 2 O-N emissions were influenced by both soil temperature and soil moisture (Table 7). Others have reported similar findings (Abagandura et al, 2019). However, our research also showed that while temperature is correlated to N 2 O emissions, this relationship may be positive in the fall and negative in the spring (Figure 4).…”

“…Even though the influence of temperature and soil moisture on N 2 O emissions has been widely studied (Linn & Doran, 1984;Sainju, Stevens, Caesar-Tonthat, & Liebig, 2012;Wagner-Riddle & Thurtell, 1998), interactions between management and these factors in the field are poorly understood (Abagandura et al, 2019). If management can produce predictable and consistent impacts on emissions, then these findings can provide a justification for adjusting the calculated agricultural carbon footprint (DeKlein et al, 2006;Han, Walter, & Drinkwater, 2017;IPCC, 2007;Snyder, Bruulsema, Jensen, & Fixen, 2009).…”

Effects of Biochar and Manure Applications on Soil Carbon Dioxide, Methane, and Nitrous Oxide Fluxes from Two Different Soils

“…The cumulative CH 4 fluxes in the 2013, 2014, and 2015 seasons under biochar and manure treatments for the two soils are shown in Table 2. No significant differences were observed in cumulative CH 4 fluxes from biochar and manure treatments in both soils (Table 2), perhaps due to the similar soil water content among treatments (Abagandura et al, 2019). Kammann et al (2012) and Wang et al (2012) also reported no significant effect of biochar on soil CH 4 fluxes compared with the CNT in the dryland cropping system.…”

“…Wagle and Kakani (2014) and Wegner et al (2018) also reported CO 2 peaks as a response to heavy precipitation. It is likely that heavy precipitation in 2014 increased microbial activity and C mineralization, causing an increase in CO 2 flux (Abagandura et al, 2019; Sainju et al, 2008, 2010).…”