Swedish University of Agricultural Sciences, Department of Biosystems and Technology, P.O. Box 190, SE-234 22 Lomma, Sweden.
Swedish University of Agricultural Sciences, Department of Biosystems and Technology, P.O. Box 190, SE-234 22 Lomma, Sweden.
Sci Total Environ. 2022 Sep 1;837:155634. doi: 10.1016/j.scitotenv.2022.155634. Epub 2022 May 2.
Establishing a cover crop after harvest of a main crop in late summer or early autumn can have several advantages, including weed control, decreased nitrate leaching and an increased potential for carbon sequestration. However, the addition of fresh plant material to the soil in late autumn or winter, either by active termination of the cover crop or by frost damage, could be a risk factor for nitrous oxide emissions, due to the simultaneous occurrence of wet soil conditions and freeze-thaw cycles. We measured field emissions of nitrous oxide from three cover crops - oilseed radish, (Raphanus sativus var. oleiformis), phacelia (Phacelia tanacetifolia) and oats (Avena sativa) - over a 43-day period in winter. All three cover crops were sensitive to frost and died, wilted and started to decompose during this period. The cover crops increased nitrous oxide emissions, relative to controls that were ploughed in autumn, by 1.8, 0.7 and 0.6 kg NO-N ha, for oilseed radish, phacelia and oats, respectively. We conclude that the choice of cover crop species and management options for cover crops need to be further researched to minimise their contribution to nitrous oxide emissions from agriculture.
在夏末或初秋收获主要作物后种植覆盖作物有几个优点，包括控制杂草、减少硝酸盐淋失和增加碳固存的潜力。然而，在深秋或冬季向土壤中添加新鲜植物材料，无论是通过主动终止覆盖作物还是通过霜害，都可能成为氧化亚氮排放的风险因素，这是由于湿土条件和冻融循环同时发生。我们在冬季的 43 天内测量了三种覆盖作物（油菜籽、苤蓝（Phacelia tanacetifolia）和燕麦（Avena sativa））的田间氧化亚氮排放。所有三种覆盖作物都对霜敏感，在此期间死亡、枯萎并开始分解。与秋季犁耕的对照相比，油菜籽、苤蓝和燕麦分别将氧化亚氮排放量增加了 1.8、0.7 和 0.6 千克 NO-N ha。我们得出的结论是，需要进一步研究覆盖作物的物种选择和管理选项，以尽量减少它们对农业氧化亚氮排放的贡献。
