Dep. of Agronomy, Horticulture and Plant Science, South Dakota State Univ., Brookings, SD, 57007, USA.
J Environ Qual. 2020 May;49(3):628-639. doi: 10.1002/jeq2.20063. Epub 2020 Mar 31.
An integrated crop-livestock system (ICLS), when managed properly, can help in mitigating soil surface greenhouse gas (GHG) fluxes, especially carbon dioxide (CO ), methane (CH ), and nitrous oxide (N O). However, the impacts of an ICLS on GHG fluxes are poorly understood. The present study was conducted at two sites (northern Brookings [Brookings-N] and northwestern Brookings [Brookings-NW]) established in 2016 and 2017, respectively, under loamy soils in South Dakota. The specific objective was to evaluate the impact of cover crops (CCs) and grazed CCs under oat (Avena sativa L.)-CCs-maize (Zea mays L.) rotation on GHG fluxes. Study treatments included the following: (a) a legume-dominated CC (LdC), (b) a cattle-grazed LdC (LdC+G), (c) a grass-dominated CC (GdC), (d) a cattle-grazed GdC (GdC+G), and (e) one without CC or grazing (NC). Greenhouse gas monitoring occurred weekly during the growing crop seasons in 2016 and 2017 for Brookings-N and in 2017 and 2018 for Brookings-NW. Data showed that cumulative CO and N O fluxes at Brookings-N were lower for GdC+G (4042 kg C ha for CO and 1499 g N ha for N O) than for LdC+G (4819 kg C ha for CO and 2017 g N ha for N O), indicating the superiority of GdC+G over LdC+G in reducing GHG fluxes. However, no effect from grazed CC on cumulative CO and N O fluxes were observed at the Brookings-NW site. Cumulative CH flux was not affected by an ICLS at either site. This short-term investigation showed that, in general, CCs and grazing of CCs and maize residue did not impact GHG fluxes.
一个综合的作物-牲畜系统（ICLS），如果管理得当，可以帮助减轻土壤表面温室气体（GHG）通量，特别是二氧化碳（CO ）、甲烷（CH ）和氧化亚氮（N O）。然而，ICLS 对 GHG 通量的影响还不太清楚。本研究分别于 2016 年和 2017 年在南达科他州的粉质土壤上建立了两个地点（北布鲁金斯[布鲁金斯-N]和西北布鲁金斯[布鲁金斯-NW]）进行，目的是评估覆盖作物（CCs）和放牧 CCs 对 GHG 通量的影响。在燕麦（Avena sativa L.）-CC-玉米（Zea mays L.）轮作下的黑麦草（LdC）和放牧 LdC（LdC+G）、黑麦草（GdC）、放牧 GdC（GdC+G）和无 CC 或放牧（NC）的处理。温室气体监测在 2016 年和 2017 年布鲁金斯-N 的作物生长季节每周进行一次，在 2017 年和 2018 年布鲁金斯-NW 进行。数据表明，在布鲁金斯-N，GdC+G（CO 的 4042kgC ha 和 N O 的 1499gN ha）的累积 CO 和 N O 通量低于 LdC+G（CO 的 4819kgC ha 和 N O 的 2017gN ha），表明 GdC+G 在减少 GHG 通量方面优于 LdC+G。然而，在布鲁金斯-NW 站点，放牧 CC 对累积 CO 和 N O 通量没有影响。在这两个地点，累积 CH 通量都不受 ICLS 的影响。这项短期研究表明，一般来说，CCs 和 CCs 以及玉米残茬的放牧并没有影响 GHG 通量。
