Detachment of road surface soil by flowing water

An agricultural watershed generally consists of two land use categories, farmland and the unpaved road or path networks with different traffic frequency and size. Road surfaces are quite different from farmland soil in physical properties, resulting in it's distinguish production transportation process. Hydraulic flume experiments were conducted with the flow discharges ranging from 1 to 5 L s^− 1 and the slope gradients ranging from 8.8% to 46.6% to simulate the soil detachment process on a road surface and to develop tools in order to calculate detachment rates occurring on that road surfaces. The results illustrate that road surfaces behave characteristically in the runoff detachment and sediment delivery process due to the difference in the bulk density and functions of agricultural soils. The soil detachment rate is closely related to flow depth, slope gradient and other hydraulic parameters such as shear stress, stream power and unit stream power. Multiple non-linear regression analyses indicate that detachment rates for all roads can be accurately predicted by power functions of flow depth and slope gradient. According to the experimental results, stream power was suggested as an indicator to estimate soil detachment rate instead of shear stress in soil erosion models. However, considering the simplicity and availability, power function of flow depth and slope gradient is also recommended to predict detachment rate on the road surfaces.     

常见肉类成分荧光PCR检测试剂盒的比较

目前市场上肉类成分检测试剂盒种类繁多。为了评价不同厂家试剂盒的应用效果,选取当前市场上4个品牌的5种肉类成分荧光PCR检测试剂盒,对其特异性、灵敏性及效率成本进行了分析比较。结果显示：4个品牌的5种肉类成分荧光PCR检测试剂盒特异性均较好,不同肉类之间没有交叉反应;但检测同一种肉类的不同品牌试剂盒及同一品牌检测不同肉类的试剂盒灵敏性存在差异;不同品牌的试剂盒检测时间和成本也有区别,A品牌耗时最短,D品牌价格最高。结果表明,不同品牌试剂盒的灵敏性、检测耗时和检测成本各有特点,使用者可根据使用目的及经费预算选择合适的试剂盒。     

Design of a cost-effective facility for family breeding programs of marine organisms

Mixture families, injury of larvae and common environmental effect greatly hamper the precision and efficiency of family breeding of marine organisms. We have designed a cost-effective facility to eliminate these problems. The facility prevents mixing of larval families, injury to larvae and greatly reduces common environmental effects. Compared to expensive re-circulated systems, this facility is easy to construct and operate, needing no electronic or computer control. Consequently, it is very appropriate for breeding programs that cannot afford expensive re-circulated systems.     

高产抗稻瘟病杂交中籼新组合Ⅱ优69

Ⅱ优69是湖北恩施州农科院选育的高产抗稻瘟病新组合,2002—2003年参加恩施水稻品种区试,平均产量8.712 t/hm2,比对照增产5.39%,2005年通过湖北省审定。介绍了Ⅱ优69的特征特性及产量表现,并提出了其高产栽培技术和制种技术要点。     

农业水利工程建设与管理中存在的问题及处理对策

我国人口众多,地域辽阔,是一个农业大国,农业水利工程是关乎国计民生的大事,本篇 文章从质量提升、制度保障、工作力度强化等三方面入手,切实提升农业水利工程的整体质量,为 人民造福。主要探析了现存于农业水利工程建设与管理中的问题,并提出了几点相对应的处理 对策,为促进农业发展尽绵薄之力。     

花梨木叶挥发油化学成分的GC MS分析

采用水蒸汽蒸馏法提取分离花梨木叶中的挥发油,通过GC—MS联用仪对花梨木叶挥发油的化学成分进行分析,共鉴定出39个化学成分,主要成分为环己甲酸乙烯酯（5．10％）、三十烷（3．76％）、5,6,7,7a-四氢-4,4,7d-三甲基-2（4H）-苯呋喃酮（3．44％）、二十八烷（3．08％）、十六酸（2．35％）、二十四烷（2．26％）、榄香素（2．25％）、二十烷（2．17％）。     

Preparation, physicochemical and texture properties of texturized rice produce by Improved Extrusion Cooking Technology

Using broken rice and rice bran as raw material, texturized rice (TR) was prepared by Improved Extrusion Cooking Technology (IECT) in which gelatinization is formed by means of low temperature and high pressure. The expansion of extrudate was hardly changed so that TR showed similar texture properties and shape with polished rices. The effect of rice bran addition (0% and 4%) and IECT conditions, including feed moisture content (26.6-33.4%), screw speed (20.1-32.6 rpm) and shearing compression metering zone temperature (SCMT, 69.8-120.2 °C) on the physicochemical, texture and nutritional characteristics of TR, were investigated by response surface methodology using Central Composite Design. When the bran addition was 4%, feed moisture content was 30%, screw speed was 26.6 rpm, SCMT was 95 °C, prepared TR contained 16.61 ± 0.02% of total dietary fiber, 9.40 ± 0.04% of protein, 3.68 ± 0.03% of fat, 2.42 ± 0.02 μg/g of thiamin, 0.52 ± 0.01 μg/g of riboflavin and 16.07 ± 0.12 mg/100 g of γ-oryzanol (dry matter content). The content increase of TDF for TR was 15.81% and the content increases of nutrients for thiamin, riboflavin, and γ-oryzanol were 1.39 μg/g, 0.24 μg/g, and 8.99 mg/g dry matter content, respectively, compared with those of polished rice.     

土下果实挖掘限深技术发展现状与展望

现阶段,我国土下果实收获机械智能化水平较低,收获时果实漏挖率和破损率较高,降低了机械化收获的作业质量。挖掘限深技术是降低果实漏挖率和破损率,提高土下果实收获机械作业性能的关键技术之一。为此,综述了国内外挖掘限深技术的发展现状,介绍了挖掘限深技术的主要类型和特点,分析了目前我国自动限深技术研究存在的问题以及发展方向,以期为我国挖掘限深技术的研究和新产品开发提供借鉴和参考。