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Remote sensing monitoring on regional crop water productivity in the Haihe River Basin 总被引:1,自引:0,他引:1
Crop water productivity (CWP) agricultural development in water scarcity is one of the important indicators for sustainable area. There is serious conflict between water sup- ply and requirement in the Haihe River Basin. CWP of winter wheat and summer maize from 2003 to 2007 in the Haihe River Basin is estimated based on large-scale evapotranspiration (ET) and crop yield obtained by remote sensing technology. Spatial and temporal distribution of CWP of winter wheat and summer maize is investigated in this study. Results show that CWP of winter wheat in most parts of the study area varies from 1.02 kg/m3 to 1.53 kg/m3, and CWP of summer maize varies from 1.31 kg/m3 to 2.03 kg/m3. Multi-year averaged CWP of winter wheat and summer maize in the study area is about 1.19 kg/m3 and 1.59 kg/m3. CWP results show certain promotion potential to alleviate the water shortage in the Haihe River Basin. Correlation analysis of CWP, crop yield and ET shows that there is great potential for crop yield promotion without the growth in irrigation water. Large-scale CWP estimated by remote sensing technology in this study shows spatial distribution features, which could be used to real-time agricultural water resource management combined with crop yield and ET. 相似文献
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黄土高原作物产量及水土流失地形分异模拟 总被引:1,自引:1,他引:1
De-farming slope farmland has been an effective measure in recent years for the improvement of the eco-environment and the mitigation of soil and water loss on the Loess Plateau. This paper, taking the Yangou Basin as a case study and using day-by-day mete- orological data of Yan'an station in 2005, simulated and analyzed the quantitative relation between crop yield, soil and water loss and topographic condition with the aid of WIN-YIELD software. Results show that: 1) topographic gradient has important influence on crop yield. The bigger gradient is, the lower the crop yield. Yields of sorghum and corn decrease by 15.44% and 14.32% respectively at 25° in comparison to the case of 0°. In addition, yields of soya, bean and potato decrease slightly by 5.26%, 4.67% and 3.84%, respectively. The in- fluences of topographic height and slope aspect on crop yield are slight. 2) Under the same topographic condition, different crops' runoff and soil loss show obvious disparity. Topographic gradient has important influence on soil and water loss. In general, the changing trend is that the soil and water loss aggregates with the increase of gradient, and the maximal amount occurs around 20°. The influence of topographic height is slight. Topographic aspect has a certain effect, and the fundamental characteristic is that values are higher at the aspect of south than north. 3) Topographic gradients of 5° and 15° are two important thresholds. The characteristic about soil and water loss with the variation of topographic gradients show that: the slope farmland with gradient less than 5° could remain unchanged, and the slope farm- land more than 15° should be de-farmed as early as possible. 相似文献
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欧佩克石油生产配额制度与油价关系研究 总被引:1,自引:4,他引:1
欧佩克(OPEC)是一个国际石油供应组织, 其石油政策的重点是通过实施生产配额制度, 对国际市场的油价进行控制, 以实现其石油收益的最大化。本文依据丰富翔实的历史及现状数据资料, 对欧佩克生产配额制度进行了深入研究后得出三点结论: 首先, 生产配额、产量与油价关系紧密, 欧佩克实施配额制度是其实施卡特尔控制的手段之一, 配额制度在欧佩克发展历史上发挥了重要作用, 尽管当前生产配额制度对油价的控制作用在一定程度上弱化, 但也正在发挥作用, 与此同时也存在一定的问题。其次, 欧佩克生产配额制度对油价的影响具阶段性特征, 本文分别对欧佩克在启动期、活跃期、挫折期、成熟期和彷徨期5个阶段中石油生产配额、产量与油价的关系进行了对比分析与研究, 得出了不同时期欧佩克生产配额、产量与油价的关系, 形成了若干重要认识。第三, 分析预测了未来欧佩克生产配额与油价的关系, 探讨了生产配额制度对世界市场油价走向的影响。 相似文献
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通过对雷州半岛蔗区甘蔗营养状况的普查 ,利用数理统计方法 ,分析了养分间、养分与经济性状间的相关关系。结果表明 :增N、提高土壤pH值可显著提高茎长 ,茎长的提高可促进单茎重、工业蔗产量、含糖量极显著提高。增K、Mg可显著提高有效茎 ,有效茎的提高可促进工业蔗产量显著提高 ,却导致锤度显著下降。偏施Mg会导致锤度极显著下降。因而采取的措施为增N、K ,合理配施镁含量低的石灰和P肥 ,以促进茎长、单茎重、有效茎的提高 ,从而提高产量 ;控施Mg肥 ,达到提高糖分含量的目的 相似文献
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