黄淮海地区冬小麦生产力时空变化及其驱动机制分析

黄淮海地区是我国重要的粮食生产基地,分析该区域粮食产量的时空变化特征及其变化机制,对我国粮食安全的评估有重要的现实意义。论文以AVH RR NDVI数据和逐日气象要素驱动土壤-植被-大气系统物质传输和作物生长的耦合模型,模拟分析1981-2000年黄淮海地区冬小麦产量的时空分布及其驱动机制。分析发现,从1981-1997年生物产量基本呈增加趋势,之后有所下降。但由于作物经济系数不断增加,整个时段冬小麦经济产量增加趋势明显,单位面积产量提高了一倍。化肥施用量的增加和优良品种的推广是增产的主要原因,而气候波动导致区域年际产量变化幅度为8.5%。黄淮海地区冬小麦产量的空间分布及其演变呈现显著的地域特性,与当地灌溉条件、土壤条件密切相关。

Spatial-temporal Evolution and Driving Forces of Winter Wheat Productivity in the Huang-Huai-Hai Region

Huang-Huai-Hai region as the main grain-producing region,its production is closely r-elated with national food safety.Spatial-temporal evolution of crop production and its driving forces in this region should be clarified for regional scale productivity trend analysis.In this paper,a coupled model of Soil-Vegetation-Atmosphere Transfer(SVAT) and crop growth dynam-ics(VIP model) driven by AVHRR NDVI and climatic variables is applied to simulate the prod-uctivity of winter wheat in the Huang-Huai-Hai region from 1981 to 2000.In this period,air temperature became warmer and sunshine duration became shortened,whereas no obvious trend for precipitation was observed.The simulated grain yields are validated with statistic yield at county level gathered in Hebei Plain.It is found that the biomass increased before 1997 and then decreased.However,due to the improvement of harvest index,per unit area grain yield grew significantly during the whole period,with per unit area grain yield doubled in 2000 over 1981.The enhanced input of fertilizer and popularization of fine crop strains are the principal reasons for grain yield increase.The consumption of fertilizer was doubled from the 1980s to the 1990s,which contributed 40% of the grain yields.At the same time,the harvest index of winter wheat improved continu-ously from 0.31 to 0.44.However,the crop productivity was disturbed by climatic variability from year to year,which contributed 8.5% of the interannual variability of regional grain output.In the study area,the spatial-temporal evolution of grain production is clearly related with local conditions and manag-ement,e.g.irrigation facilities and soil conditions.The increment of grain yield is different in these 20 years.In the 1980s,there were 46% of the areas with an yield improvement by 30%,some areas even as high as 100%.However,the increment obviously stepped down in the 1990s,with the enhancement ranging between 15% and 30% in about 55% of the areas,and only 30% of the areas with an yield increment exceeding 30%.The grain yield of wheat in the Huang-Huai-Hai region has reached its plateau,which is supported by excess consumption of surface and ground water.To keep the agriculture sustainable in this area,water conservation and saving techniques and engineering projects should be widely improved.