华北平原夏玉米不同施氮措施的综合增温潜势研究

Study on the global warming potential of summer maize under different nitrogen application rates in North China Plain

关键词:  华北平原  夏玉米  温室气体  生命周期  综合增温潜势

Key words:  North China Plain  summer maize  greenhouse gases  life cycle  global warming potential

摘要:

为探究和利用高固碳、低排放的农业管理措施，以华北平原夏玉米生产为研究对象，采用大田试验和生命周期评价方法，设置对照(CK)、低氮肥(LF)、适宜氮肥(SU)、减排(适宜氮肥+抑制剂，ER)以及高氮肥(HF)5种施氮处理，定量评估夏玉米生产全过程中的土壤排放温室气体增温潜势(GWP_Soil)、农业投入增温潜势(GWP_Indirect)、净初级生产力增温潜势(GWP_NPP)、净综合增温潜势(Net GWP)和农田经济效益。结果表明:不同处理总排放增温潜势(GWP_Soil+GWP_Indirect)为10 831.3~14 301.9 kg/hm²(以CO₂当量计)，由高到低依次为HF>SU>LF>ER>CK；HF的GWP_Soil及GWP_Indirect均为最高，较CK处理分别高10.9%和153.3%；GWP_Soil对总排放量的贡献较大(>70%)，农业投入中肥料对GWP_Indirect的贡献最大，为54.1%~69.7%(CK除外)，灌溉次之；华北平原夏玉米农田Net GWP为负值，是大气的碳汇，SU和ER处理Net GWP最大，绝对值分别较CK处理高 18.1% 和17.9%。综上，ER和SU处理净利润最高，属于高收益-高固碳种植管理模式，但ER与SU处理相比，ER的GWP_Soil降低了8.7%，更有利于温室气体减排，适合作为绿色农业发展模式在华北平原推广。

Abstract:

In order to explore and utilize agricultural management measures with high carbon sequestration and low emissions, summer maize production in the North China Plain was taken as the research object. Based on field experiments and life cycle assessment methods, five nitrogen application treatments including control check(CK), low nitrogen fertilization(LF), suitable fertilizer utilization(SU), emission reduction(suitable nitrogen with inhibitor, ER)and high nitrogen fertilizer(HF)were conducted to quantitatively evaluate the warming potentials of soil greenhouse gas emissions, agricultural inputs(GWP_Indirect), and net primary productivity(GWP_NPP). The net comprehensive warming potential(Net GWP)and the economic benefits in the whole process of summer maize production were also investigated. The results showed that: The total warming potential(GWP_Soil+GWP_Indirect)of emissions ranged from 10 831. 3 to 14 301. 9 kg/hm²(measured in CO₂ equivalent)under different treatments, with HF>SU>LF>ER>CK in descending order. The GWP_Soil and GWP_Indirect of HF were the highest, 10. 9% and 153. 3% higher than those of CK, respectively. GWP_Soil made major contributions to the total emissions(>70%), while fertilizer contributed the most to GWP_Indirect in agricultural inputs, accounting for 54. 1% to 69. 7%(except CK), followed by irrigation. The Net GWP of summer maize farmland in North China Plain was negative, which was the carbon sink of the atmosphere. SU and ER treatments had the largest Net GWP, which was 18. 1% and 17. 9% higher than CK treatment, respectively. To sum up, the net profits of ER and SU treatments were the highest and these two treatments belonged to the high yield-high Net GWP planting management mode. However, the GWP_Soil value of ER reduced by 8. 7% compared with SU treatment. Therefore, ER treatment was more conducive to realize greenhouse gas emission reduction and suitable to be promoted as a green agricultural development mode in the North China Plain.