Nutrient management has led to unprecedented increase in crop production, but with significant carbon (C) trade-off that has close nexus with energy flow. We quantified the impacts of nutrient management on emission of greenhouse gases, net ecosystem C budget (NECB) and energy flow in three cropland ecosystems (rice–wheat, maize–wheat and cotton–wheat). Carbon dioxide (CO₂) and nitrous oxide (N₂O) emissions were significantly (p < 0.05) higher in rice than cotton, while maize ecosystem was in-between. The greenhouse gas intensity was significantly higher for rice–wheat (by 0.2 kg CO_2e kg⁻¹ grain) and maize–wheat (by 0.1 kg CO_2e kg⁻¹ grain), compared with cotton–wheat. The higher carbon emission ratio for maize–wheat (9.59) and rice–wheat (8.07) suggested their higher potential to fix C per unit loss, compared with cotton–wheat (7.03). Atmospheric CO₂ assimilated into net primary production (NPP) totalled 14.1 ± 0.18, 11.5 ± 0.13 and 9.7 ± 0.13 Mg C ha⁻¹ for rice–wheat, maize–wheat and cotton–wheat ecosystems, respectively. With an estimated net ecosystem exchange of 9.5 ± 0.29, 5.8 ± 0.19 and 2.7 ± 0.23 Mg C ha⁻¹, respectively, for three ecosystems, rice–wheat (2427 kg C ha⁻¹ year⁻¹) had significantly higher NECB, compared with maize–wheat (27.1 kg C ha⁻¹ year⁻¹) and cotton–wheat (− 3834 kg C ha⁻¹ year⁻¹). Rice–wheat had significantly higher C addition in soil organic carbon (SOC) pool, compared with other two ecosystems. Conversely, cotton–wheat had depletion of SOC pool (− 817 kg C ha⁻¹). Although the three ecosystems did not differ significantly for fertilizer-related energy input (E_I), energy output (E_O), energy ratio (E_R) and net energy gain were significantly higher for cotton–wheat, compared with other ecosystems.

营养管理已导致作物产量空前提高，但碳（C）的权衡取舍与能量流动密切相关。我们量化了养分管理对三种农田生态系统（稻－小麦，玉米－小麦和棉花－小麦）中温室气体排放，净生态系统碳预算（NECB）和能量流的影响。 水稻中的二氧化碳（CO ₂）和一氧化二氮（N ₂ O）排放量显着高于棉花（p <0.05），而玉米生态系统介于两者之间。温室气体强度显著更高为稻麦（0.2公斤CO _2E 千克^-1谷物）和玉米小麦（0.1公斤CO _2E千克^-1谷物），而不是棉麦。与棉麦（7.03）相比，玉米-小麦（9.59）和水稻-小麦（8.07）较高的碳排放比表明它们具有更高的固定单位损失碳的潜力。稻麦，玉米麦和棉麦生态系统中，被吸收为净初级生产（NPP）的大气CO ₂总计分别为14.1±0.18、11.5±0.13和9.7±0.13 Mg C ha ^-1。估计三个生态系统的净生态系统净交换量分别为9.5±0.29、5.8±0.19和2.7±0.23 Mg C ha ^-1，相比之下，稻麦（2427 kg C ha - ¹ 年^-1）的NECB显着更高。玉米-小麦（27.1 kg C公顷- ¹ 年^-1）和棉花-小麦（− 3834 kg C公顷- ¹ 年^-1）。与其他两个生态系统相比，稻麦在土壤有机碳（SOC）库中的碳添加量明显更高。相反，棉/小麦的SOC储备不足（− 817 kg C ha ^-1）。尽管三种生态系统的肥料相关能量输入（E _I）没有显着差异，但是与其他生态系统相比，棉小麦的能量输出（E _O），能量比（E _R）和净能量获取显着更高。