缓释型油菜专用配方肥在直播油菜生产上的应用研究

在湘东地区的直播油菜生产中引进新型缓释型油菜专用配方肥“宜施壮”,对其在直播油菜生产上的应用效果进行了研究。结果表明,施用缓释型油菜专用配方肥,避免了普通一次性施肥因肥料流失而导致的油菜后期早衰,且对促进冬前绿叶数的增加,延长角果表层叶绿素的光合寿命效果明显,增产效果显著,且投入产出比高,在省工、节本、增产等方面存在着一定的优势。     

六圆弧蛋形断面正常水深直接计算方法

【目的】研究六圆弧蛋形断面正常水深的简单计算方法,为该断面的工程设计提供技术支持。【方法】根据面积分割法计算六圆弧蛋形断面的面积、湿周和水力半径,根据明渠均匀流理论计算不同流量时渠道的正常水深,通过优化拟合研究蛋形断面正常水深的简单计算方法。【结果】优化拟合得到了蛋形断面水深处于不同位置时相对断面面积、相对湿周、相对水力半径的计算公式,确定了正常水深与流量的关系及水深的迭代计算公式,通过优化拟合研究,最后给出了正常水深的简化计算公式。【结论】所建立的六圆弧蛋形断面正常水深的理论计算公式和近似计算公式计算过程简单、精度高,平均误差为0.204%,最大误差为1.129%。     

Status of a commercial sea scallop enhancement project in Iles-de-la-Madeleine (Quebec, Canada)

The main objective of the REPERE (REcherche sur le Petoncle a des fins d'Elevage et de REpeuplement) research programme, initiated in the Iles-de-la-Madeleine in 1991, was to enhance natural sea scallop (Placopecten magellanicus) populations which were greatly reduced by overfishing. Sea bed seeding was chosen as the best approach to achieve this goal. In 1992, after two years of scientific research work, mainly centred on producing a supply of juveniles and developing intermediate culture methods, the Scallop Fishermen's Association, supported by governmental financing, initiated a commercial seeding project. Two thousand collectors were set out in open waters suitable for spat settlement. A collecting rate of 780 spat per collector produced a catch of 1.5 million spat. Technical problems led to significant losses of juveniles. Intermediate culture in pearl nets in a lagoon, between July and October 1993, enhanced growth noticeably. At an age of 1 y, average shell height was 32 mm. In the fall of 1993, 30 000 young scallops were seeded on a natural bed closed to fishing. Ten thousand collectors were set out in the fall of 1993. Collecting success was 1145 spat per collector and spat losses were reduced by technical improvements. In November 1994, 1.5 million scallops were seeded on a sea bed closed to the fishery. Scallops from the 1994 seeding could reach market size (90 mm) by 1997.     

New USB-based 3D digital echo sounder system for mapping and assessing fish and aquatic plants

A recently developed echo sounder with a global positioning system (GPS) receiver can display both the boat position and echo gram. However, this information is displayed in different views. In this paper, we present a new digital three-dimensional (3D) echo sounder system comprising a traditional analog echo sounder, GPS receiver, notebook personal computer (PC), and a low-cost, compact, self-developed universal serial bus (USB)-based analog-to-digital (A/D) converter board. Multiple echo views can simultaneously display various desired targets more clearly than the view in a traditional analog echo sounder. The newly developed analysis software can precisely extract the information related to bottom depth, plants, and fish schools from the echoes. By combining the acoustic and position data, the system can map both the fish and plant echoes on the 3D sea bed generated from the extracted bottom depth. This system has been proved to be useful in observing the 3D and wide-area distribution of both fishes and aquatic plants and in studying habitat parameters in aquatic ecosystems. A notebook PC equipped with the self-developed USB-based A/D converter board is capable of transforming any traditional analog echo sounder into a high-performance 3D digital echo sounder.     

普通野生稻DNA导入栽培稻后代的苗期耐盐性鉴定

采用营养液水培法对普通野生稻DNA导入宁夏栽培水稻宁粳16号中获得的12份后代材料进行苗期的耐盐性鉴定.结果表明,在120 mmol/L NaCl处理下,材料D44、D43、D5-24、DJ 13、DJ 24和D 5-45的平均死叶率相对较低,地上和地下部能够保持较高的含水量,说明其受盐胁迫的伤害较小;所有材料的可溶性糖含量和脯氨酸积累量都较0 mmol/L NaCl的高,其中材料D43、D44、D5-24、DJ 24、DJ 25和DJ13的可溶性糖含量提高的量较其他材料高,而脯氨酸的相对积累量较其他材料低,说明这几个材料的渗透调节能力较强,相对于其他材料较耐盐.     

覆草对旱种直播稻产量与品质的影响

直播水稻品种扬稻6号(籼)和扬粳4038(粳), 并设覆草(麦秸秆)旱种、无覆盖旱种和无覆盖水种(出苗后保持浅水层)处理, 研究了对水稻产量与品质的影响及其生理原因。结果表明, 与无覆盖水种(对照)相比, 两旱种处理的产量都有不同程度的降低, 覆草旱种减产1.9%~6.6%, 差异不显著, 无覆盖旱种减产18.0%~27.6%, 差异显著。覆草旱种显著提高了稻米的整精米率、胶稠度、清蛋白和谷蛋白含量, 显著降低了垩白米率、垩白度和醇溶蛋白含量, 还改善了稻米的食味性。无覆盖旱种直播结果则相反。覆草旱种可以获得较高的产量并可改善稻米品质的重要生理原因是增加了结实期剑叶膜质过氧化酶活性、光合速率、根系活力以及根系中吲哚-3-乙酸和玉米素+玉米素核苷的含量。无覆盖旱种降低了上述指标值, 致产量显著下降、米质变劣。     

基于ANSYS的大耕深旋耕刀结构优化设计

通过对现有R245旋耕刀的建模及静力学分析,以旋耕刀主导用材之一65Mn的屈服强度为依据,确定了R245旋耕刀所承受的极限载荷与工作载荷。采用等比例放大的方法,以GB/T5669-2008规定的R245旋耕刀结构为基础,设计了刀尖回转半径为300mm旋耕刀(其耕深可达20~22cm),同时以同比例放大确定了R300旋耕刀的极限载荷与工作载荷,基于ANSYS软件对所设计的R300旋耕刀在工作载荷下的应力场进行了模拟,并基于模拟结果重点对其刀刀柄尺寸进行了优化。结果表明:当刀柄厚度增加到25mm、刀柄宽度增加到40mm后,R300旋耕刀不仅在工作载荷下不会失效而且在极限载荷下也不会失效。     

旱地玉米垄膜沟种微集水种植技术研究

为提高我国北方旱地玉米的水分利用效率和土壤温度,以达到进一步增产的目的,设计出一套旱地玉米的垄膜沟种微集水种植技术。通过对比试验发现:单向丁风垄(D 2)种植沟间的含水量,较对照和平铺膜提高2.87%和1.82%;水分利用效率也最高,达18.05 kg/hm2.mm,较对照和平铺膜提高48.70%和25.54%。整个生育期种植行间各层平均地温,垄膜沟种技术高出对照1.4℃,高出平铺膜0.1℃;总积温在2 901.0~2 984.7℃之间,平铺膜为2 908.7℃,对照仅为2 699.3℃。垄膜沟种平均产量为7 237.26 kg/hm2,其中单向顺风垄(D 1)的产量最高,达7 569.62 kg/hm2,较对照和平铺膜提高47.72%和21.46%。     

盐渍化改造区土地利用变化对地下水资源的影响 --以河北省曲周县为例

运用GIS空间分析功能、柯布—道格拉斯生产函数以及曲周县统计资料和地下水资料,分析了近20年来土地利用变化及其对地下水资源的影响,研究结果表明,作为盐渍化改造区以农业为主的曲周县,土地利用变化速度不快且土地用途转移主要是耕地转变为农村居民点和城镇用地;耕地灌溉率、复种指数、耕地灌溉面积、粮食产量不断提高;粮食和蔬菜产量对地下水资源的高度依赖性,是引起地下水埋深变化的主要原因;依据河北省地下水超采区划分标准,曲周县浅层地下水开采区是基本平衡区,深层开采区属于中度超采区。为实现盐渍化改造区水土资源的可持续利用,必须调整种植业结构,适当降低土地利用集约度,大力发展节水农业。     

新型立式复合圆盘大豆精密排种器研究

一种双体立式复合圆盘重力清种结构形式排种器，在继承和发展了传统立式圆盘排种器结构简单、布置方便以及作者前期设计的侧充重力清种立式圆盘排种器不伤种、工作阻力小等优点的基础上，通过深入的理论分析及试验研究，完成了型孔参数优化、具有良好工艺性及工作性能的防堵塞机构设计，以及创新性地采用双体复合圆盘的结构形式，有效改善了种子充填环境、排种质量，并成倍提高了机械式精密排种器的作业速度及可靠性。突出的性价比是其重要特征。