基于GIS的河南省小麦区域节肥减排潜力评价

GIS-BASED EVALUATION OF THEIR MITIGATION POTENTIAL OF FERTILIZER APPLICATION AND GREENHOUSE GAS EMISSION AT DIFFERENT WHEAT PLANTATION REGIONS IN HENAN, CHINA

关键词:  地理信息系统  节肥潜力  空间变异  温室气体排放  生命周期评价

Key words:  GIS  fertilizer saving potential  spatial variation  greenhouse gas emission  life cycle assessment

摘要:

目的 为研究河南省小麦节肥减排潜力。方法 文章基于农业统计数据、2 063份农户小麦调研数据和1 582组小麦田间试验数据，采用ArcGIS系统分析河南省农户习惯管理下小麦氮磷钾肥施用量及区域间差异，评价不同区域与推荐施肥相比的节肥潜力；应用生命周期评价（life cycle assessment，LCA）方法，定量河南省及不同区域小麦温室气体（greenhouse gas，GHG）减排潜力及区域性差异，为我国农业可持续发展和环境保护提供科学依据。结果 （1）河南省农户小麦习惯施氮量平均198 kg/hm²（174~259 kg/hm²），其中东部和北部相对较高，中部和南部较低；在节氮量方面，小麦单位面积节氮量平均为42 kg/hm²，在县域水平上差异很大，整体上由南往北逐渐增加。（2）农户小麦习惯施磷量平均为121 kg/hm²（64~210 kg/hm²），呈现北高南低、中部高低交错。平均单位面积节磷量为16 kg/hm²，以15~55 kg/hm²范围内的区域所占比例最大。（3）全省农户小麦钾肥习惯施用量平均50.4 kg/hm²，变化范围19~112 kg/hm²，施钾量普遍偏低，东部和北部及信阳南部县市施钾量仅19~35 kg/hm²；小麦节钾量范围为-45~62 kg/hm²，平均为-15 kg/hm²，有71.4%的县市需要增施钾肥。（4）在节肥总量方面，河南省小麦氮磷钾节肥总量分别为23.10万t、8.88万t、-5.31万t。（5）河南省小麦GHG减排总量为348.65万t CO₂ eq，单位面积温室气体减排潜力整体呈现出由南向北逐渐增加的趋势，范县、辉县、濮阳等县市的单位面积减排潜力可高达>1 000 kg CO² eq/hm²。结论 在当前河南省小麦施肥状况下，推荐施肥具有很大的节肥和减排潜力，但也表现出很强的区域性差异，根据不同区域小麦习惯施肥量和推荐量，确定节肥减排目标并制定相关措施，对小麦生产中资源节约和环境保护有重要意义。

Abstract:

Based on databases from 2 063 farmers' surveys and 1 582 wheat field trails, this study firstly employed the ArcGIS system analysis to evaluate nitrogen (N), phosphorus (P) and potassium (K) fertilization rates under the local farmers' practice and the NPK fertilizer mitigation potential compared with their recommended fertilization; and employed the Life Cycle Assessment (LCA) to quantify the differences in reduction potential of greenhouse gas (GHG) emission, in different wheat plantation regions of Henan province for a sustainable agriculture development and environmental protection. Results showed that the N fertilization rates by the farmers' practice in Henan ranged from 174 to 259 kg/hm², with an average of 198 kg/hm², which was generally relatively low in the central and southern regions, while relatively high in the eastern and northern regions. The averaged N fertilizer application was reduced by 42 kg/hm² and varied greatly with a gradual increase trend from the south to north regions at the county level. The P fertilization rates ranged from 64 to 210 kg/hm² (averaged in 121 kg/hm²) and varied with a change trend of low in the south and high in the north region, while a mixed high and low fluctuation trend in the central region. The averaged P fertilizer application was reduced by 16 kg/hm² (15~55 kg/hm² in most regions). The K fertilization rates were traditionally generally low in the whole Henan, ranged from 19 to 112 kg/hm² (averaged in 50.4 kg/hm²) and as low as from 19 to 35 kg/hm² in the north, east regions and the southern Xinyang city. The averaged soil K depletion was -15 kg/hm² (-45 to 62 kg/hm²), indicating that K fertilization was urgently required for 71.4% of these wheat plantation regions. Compared with the recommended fertilization, the total mitigation potential of the current N, P and K fertilization in Henan was 231 thousand tons, 88.8 thousand tons and -53.100 thousand tons, respectively. The total mitigation potential of GHG emission in Henan was 348.65 × 10⁴ t CO₂ eq. The capacity of the GHG emission reduction per unit area showed a gradual increase trend from the south to north regions, and could be reached as high as >1 000 kg CO₂ eq/hm², particularly in Fan county, Hui county, and Puyang city. As a result, compared with the recommended fertilization, a great potential of reducing fertilizer application and mitigating GHG emission was displayed under the farmer’ fertilization practice, although with a varied regional differences in wheat plantations in Henan. According to their currently traditional and recommended fertilization rates, a rational determination of their mitigation targets and strategies in fertilizer application and GHG emission reduction is pivotal for effective resource utilization and environmental protection in different wheat plantation regions.