黄河流域农业生产活性氮排放的时空特征研究

Spatio-temporal characteristics of reactive nitrogen emission from agricultural production in the Yellow River Basin

黄河流域是我国的粮食主产区,流域生态保护和高质量发展是当前生态文明建设的核心内容.而活性氮排放是造成水体、大气及气候变化等环境问题的重要因素,已经严重威胁到人类的健康和安全.通过排放因子法对黄河流域2000、2005、2010年农业生产活性氮(Reactive Nitrogen, Nr)排放量进行核算,探讨其时空变动特征.结果表明:(1)3个年份黄河流域农业生产中活性氮排放总量分别为2185.24、2474.03、2239.96 Gg,其中,N_(2)O排放量分别为43.95、49.96、48.63 Gg, NH_(3)排放量分别为615.39、715.08、680.70 Gg,进入到水体的Nr(Nr-wp)排放量分别为1522.01、1704.95、1505.82 Gg, NO_(x)排放量分别为3.89、4.04、4.82 Gg;(2)Nr-wp、NH_(3)、N_(2)O、NO_(x)排放占总量的比重分别为67.23%~69.65%、28.16%~30.39%、2.01%~2.17%、0.16%~0.22%;(3)黄河流域活性氮年平均排放量最高的省份为河南,达到579.40 Gg,其他省份由高到低依次是陕西、山西、山东、甘肃、宁夏、内蒙古、青海、四川,其中,四川的年均排放量最低为94.41 Gg,呈中下游省份排放大于上游省份的分布态势;活性氮排放年均增长率以内蒙古最高,达4.78%,其他省份由高到低依次为宁夏、甘肃、四川、青海、河南、陕西、山东、山西,其中,山西年均增长率最低为-2.57%,年均增长率分布与年均排放量相反,呈中下游省份低于上游省份的格局;(4)各省份4种形态活性氮排放量的组成与黄河流域整体相似:山西4种形态活性氮排放量均呈下降趋势,山东NH_(3)、N_(2)O和Nr-wp排放量有所下降,其他省份均呈增长趋势;Nr-wp、NH_(3)年均排放量最大和最小的省份均为河南、四川;N_(2)O、NO_(x)年均排放量最小的省份均为青海,年均排放量最高的省份分别为河南、山西.通过分析黄河流域农业生产中活性氮排放的时空格局,可为协调黄河流域的人地关系提供科学基础,对黄河流域制定活性氮减排策略具有重要的参考意义.

The Yellow River basin is the main grain-producing area in China.Ecological protection and high-quality development in the basin are the core contents of ecological civilization construction.Reactive nitrogen emission is an important factor causing environmental problems such as water and atmosphere pollutions and climate change,which have seriously threatened human health and safety.The emission factor method was used to calculate the active nitrogen emissions from agricultural production in the Yellow River Basin in 2000,2005 and 2010,and the spatial-temporal variation characteristics were discussed.The results showed that:(1)The total reactive nitrogen emissions in the Yellow River basin in the three years were 2185.24,2474.03 and 2239.96 Gg.N2O emissions were 43.95,49.96 and 48.63 Gg,respectively.NH3 emissions were 615.39,715.08 and 680.70 Gg,respectively.Nr-wp emissions were 1522.01,1704.95 and 1505.82 Gg respectively.NO_(x) emissions were 3.89,4.04 and 4.82 Gg,respectively.(2)Nr-wp,NH3,N2O and NO_(x) accounted for 67.23%~69.65%,28.16%~30.39%,2.01%~2.17%and 0.16%~0.22%,respectively.(3)The province with the highest annual average emissions in the Yellow River basin is Henan,with 579.40 Gg;It is followed by Shaanxi,Shanxi,Shandong,Gansu,Ningxia,Inner Mongolia,Qinghai and Sichuan,among which Sichuan has the lowest annual average emissions of 94.4 Gg,showing the distribution trend that the emissions of middle and lower provinces are greater than those of the upper provinces.The provinces with the highest annual growth rates in emissions is Inner Mongolia,reaching 4.78%.It is followed by Ningxia,Gansu,Sichuan,Qinghai,Henan,Shaanxi,Shandong and Shanxi,among which the average annual growth rate of Shanxi was the lowest with-2.57%.Its distribution was contrary to the average annual emissions,showing a pattern that the middle and lower reaches provinces were lower than the upper reaches.(4)The variation of four forms of Nr emissions in each province is similar to that in the Yellow River basin as a whole.In Shanxi,the emission of NH3,N2O and Nr-wp decreased,while in other provinces,the emission of NH3,N2O and Nr-wp increased.Henan and Sichuan are the provinces with the largest and smallest annual Nr-wp and NH3 emissions.The provinces with the smallest annual emissions of N2O and NO_(x) are Qinghai,and the highest annual emissions are Henan and Shanxi.By analyzing the temporal and spatial pattern of reactive nitrogen emission in agricultural production in the Yellow River Basin,it can provide a scientific basis for coordinating the human-land relationship in the Yellow River Basin,and it is of great reference significance for the formulation of reactive nitrogen emission reduction strategies in the Yellow River Basin.