摘要
为揭示村域氮素排放特征,以河北正定新安村为例,通过2016—2018年两个轮作周期对农户作物管理、作物产量等信息实地调研、取样分析,运用NUFER-Farm模型系统,研究了新安村氮素时空排放特征及其与作物种类、施氮量、灌溉、土壤质地等的关系。结果表明,两个轮作周期单位面积农田氮素总排放量和氧化亚氮排放量差异不显著,而硝态氮淋洗量和氨挥发量差异显著,第二个轮作周期单位面积农田硝态氮淋洗量和氨挥发量分别比第一个轮作周期增长60.1%和减少13.8%,造成差异显著的原因主要是气象条件和作物种类。季节上,两年单位面积农田氮素总排放量均为秋冬春季显著大于夏季。村内临近田块氮素排放差异较大,空间分布规律不明显;但到村域尺度,不同方位氮素排放空间分布上存在一定规律,如西北、东北、东南、西南方位单位面积农田氮素总排放量平均值分别为66.8、60.2、59.6、52.3 kg N·hm^-2,其中西南方位氮素排放显著低于其他方位。村域农田氮素排放受到作物种类、施氮量、灌溉次数与土壤质地等因素显著影响。其中当地主要作物冬小麦、夏玉米和大豆单位面积农田氮素总排放平均值分别为40.5、28.5 kg N·hm^-2和5.3 kg N·hm^-2,差异显著;两个轮作体系氮素总排放量均随施氮量、灌溉次数的增加而呈现增加的趋势;土壤质地对农田氮素总排放量也有较大影响,其中砂土、砂壤土和壤土单位面积农田氮素总排放平均值分别为78.2、60.4 kg N·hm^-2和51.0 kg N·hm^-2,依次降低。总之,村域农田氮素排放具有较大的时空差异,更多受到田块作物种类、土壤条件、管理因素的影响,因此,村域氮素减排要针对田块采取优化施氮、节水灌溉、调整作物布局等措施。
A case study was conducted in Xinan Village,Zhengding County,Hebei Province to reveal the characteristics of nitrogen emissions at the village level.It was based on sampling analyses and field investigations of crop management by farmers.Crop yield and other characteristics were also considered over two rotation cycles from 2016 to 2018.The NUFER-Farm model system was used to study the spatial and temporal characteristics of nitrogen emissions from Xinan village and their correlation with crop types,nitrogen input levels,frequency of irrigation,and soil texture.The results showed that total nitrogen(TN)emission and nitrous oxide(N2O)emissions per unit area of farmland were not significantly different over the two rotation cycles.In contrast,the nitrogen losses caused by nitrate-nitrogen leaching and ammonia volatilization were significantly different.Compared with the first rotation cycle,the nitrate-nitrogen leaching and ammonia volatilization per unit area of farmland in the second rotation cycle increased by 60.1%and decreased by 13.8%,respectively;these significant differences were attributed to meteorological conditions and crop types.In terms of season,the TN emissions per unit area of farmland was significantly greater in autumn-winter-spring than in summer throughout the two years.The difference in the nitrogen emissions between adjacent fields in the village was large,and there was no clear spatial distribution law.However,considering the village as a whole,there were certain patterns in the spatial distribution of the nitrogen emissions in different directions.The average TN emission rate in the northwest,northeast,southeast,and southwest were 66.8,60.2,59.6 kg N·hm^-2,and 52.3 kg N·hm^-2,respectively;the nitrogen losses in the southwest were significantly lower than those in other directions.The nitrogen emissions of farmlands at village level were significantly affected by crop type,nitrogen input level,frequency of irrigation,and soil texture.The average TN emission rate of local main crops presented significant differences;for example,the values for winter wheat,summer maize,and soybean were 40.5,28.5 kg N·hm^-2,and 5.3 kg N·hm^-2,respectively.The nitrogen emissions presented an increasing trend with a high nitrogen fertilizer input and irrigation frequency over the two crop rotation systems.The soil texture of the farmland also had a great influence on the nitrogen emissions.The nitrogen emission rate of sand,sandy loam,and loam soil were 78.2,60.4 kg N·hm^-2,and 51.0 kg N·hm^-2,respectively.In short,nitrogen emissions at the village level displayed a large temporal and spatial variation and were affected mainly by crop types,soil conditions,and management measures.Therefore,measures to reduce the nitrogen emissions at this level should be applied to optimize nitrogen fertilization irrigation,and distribution of crops.
作者
陈帅
辛思颖
佟丙辛
吕敏娟
吉庆凯
马文奇
魏静
CHEN Shuai;XIN Si-ying;TONG Bing-xin;LÜMin-juan;JI Qing-kai;MA Wen-qi;WEI Jing(College of Resources and Environment Sciences,Hebei Agricultural University,Baoding 071000,China)
出处
《农业环境科学学报》
CAS
CSCD
北大核心
2020年第6期1351-1358,共8页
Journal of Agro-Environment Science
基金
“十三五”国家重点研发计划项目(2016YFD0200403)。
关键词
种植体系
农田氮素
时空变化
影响因素
planting system
farmland nitrogen
spatio-temporal variation
influencing factor