Conversion Margins for the Major Uses of Agricultural Land and Their Variations in Shandong Province, China

It is of practical significance for the decision-making on country food security and farmland protection to analyze the conversion margins for the major uses of agricultural land and their variations. Based on the panel data of wheat, corn, vegetable, fruit, and forests productions from 520 investigated farmer households of 13 investigated villages in Shandong Province from 2003 to 2009, and using Cobb-Douglas production function, the revenue conversion margins can be obtained separately, between different grain-crops (wheat, corn) and different non-grain crops (vegetable, fruit, forests), and the conversion relationship between growing grain( wheat, corn) and going out for non-farm work. The results show that from 2003 to 2009, growing wheat and corn are more economically and reasonably for farmers, compared with growing vegetable, but growing wheat and corn are becoming less economically and less reasonably day by day, compared with planting forests. Moreover, the conversion margin between wheat and fruit shows obvious scissors difference. Just from 2007, farmers’ growing fruit became economically and reasonably, but until 2009, compared with going out to work after abandoning farm8land, growing wheat had no economic rationality. From 2003 to 2009, farmers’ growing corn is more profitable than growing fruit and going out for non-farm work after abandoning farmland. The subsidies for wheat and corn have increased farmers’ comparative income from food production remarkably, but the subsidies cannot change the general tendency that farmers transform food (wheat, corn) production into non-food (especially forests) production. The revenue difference between growing wheat, corn and vegetable and growing fruit and forests is being pulled ceaselessly bigger, and the tendency that farmers transform wheat, corn and vegetable growing lands into fruit and forests growing lands has become increasingly apparent.     

空气"维生素"--负离子

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国际油气管道运输企业环境管理的先进经验及启示 以加拿大Enbridge公司为例(一)

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山东省工业废水排放量GM（1,1）高阶残差预测模型

介绍了ＧＭ（１，１）高阶残差预测模型之建模方法。以山东省工业废水排放量为例，建立了ＧＭ（１，１）高阶残差预测模型。结果表明，ＧＭ（１，１）高阶残差模型经ＧＭ（１，１）模型更贴近实际。     

平板膜-生物反应器工程化应用研究

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干旱区地表石油污染物风蚀作用大气传输量估算研究

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奎屯垦区居民生活饮用水现状分析

通过对奎屯垦区居民生活饮用水现状调查资料的综合分析．说明垦区居民饮水卫生最主要的是解决氟、砷及细菌超标问题，彻底改水是防治地方性饮水型氟、砷中毒的关键。同时强调我区居民对水源卫生防护重视不够，饮水水源受生活污染的影响比较严重，应加强水质监督，以保证饮用水的质量．     

高压脉冲电晕处理发动机尾气中的NO的实验研究

本文通过对高压脉冲电晕放电产生的等离子体活性物质对发动机尾气中的NO进行活化 ,研究其净化率与电压、频率、风速以及初始浓度的关系及其相互之间的影响 ,同时研究NO的产物NO2 随电压、频率、风速以及初始浓度的生成关系 ,实验表明 ,NO的净化率能够达到 5 0 %以上 ,在风速不大的条件下 ,NO转化的主要产物为NO2     

环境监测优化布点黑箱理论模型的研究

提出黑箱理论模型优化环境监测布点，根据Ｍｏｏｒｅ Ｐｅｎｒｏｓｅ广义逆理论提出二次多项式方程的最小范数算式。应用于大气监测优化布点的实例结果表明，该方法用于监测优化布点是可靠的     

川中丘陵区荒坡利用方式对水土流失影响的研究

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