机械穴直播对杂交水稻生长及产量的影响

以超级籼粳杂交稻甬优538为试材,研究了机械穴直播在不同播种量(45 kg/hm~2和60 kg/hm~2)条件下对水稻生长及产量的影响。结果表明,采用机械穴直播技术,虽然出苗率有所下降,但成穗率高,改善了直播稻的生长条件,降低了基部节间的弯曲力矩,使生育后期的倒伏风险明显降低;机械穴直播提高了每穗粒数、结实率和千粒重,产量较人工撒播提高了1.63%~5.48%。     

液压低频振动钻削系统的设计

介绍了振动钻削机械系统及扭矩检测系统的设计及构造,并利用该系统对若干典型材料进行振动钻削试验.结果表明:振动钻削具有钻削扭矩小、钻孔扭矩波动小等工艺效果.     

黄土路堑边坡钻穴栽植容器苗技术及施工工艺试验研究

黄土路堑边坡坡度大、土质差、难以蓄水保墒,加之坡陡难以站人,绿化施工难度大,植物栽种成活率低,水土流失严重,进而成为绿色通道线上的空白段,不仅严重地影响着绿色通道建设的连续性和应用的景观效果,而且还直接关系到交通运输的安全运行,为此,我们开展了黄土路堑边坡植物防护技术试验,在坡面栽植容器苗的过程中,通过改进搭架技术、打点技术、钻穴技术等独特的栽植技术及施工工艺不仅提高了植功效率,使苗木存活率达到99%以上,而且还取得了良好的坡面防护效果和景观效果。     

Assessment of tillage strategies to decrease nitrate leaching in the Brimstone Farm Experiment, Oxfordshire, UK

Tillage may influence nitrate losses from agricultural soils. Losses of nitrate were measured in drainflow at 60 cm depth and in combined surface runoff and interflow in the A horizon (=surface layer flow) on hydrologically sealed plots with a two-year comparison (1988–1990) of shallow-tine cultivation vs. mouldboard ploughing. Ploughing increased concentrations and loadings of nitrate in drainflow and surface layer flow, especially in the first year. After these two years the shallow-tined plots were ploughed to plant winter beans (Vicia faba L.), and nitrate in drainflow then increased over the next three winters, slightly exceeding that from the plots which had been ploughed throughout for winter cereals. The composition of the surface layer flow did not show this effect, however. Calculations of net winter mineralisation of soil organic nitrogen showed that shallow-tine cultivation may have decreased mineralisation slightly compared with ploughing in the first two years. These calculations did not indicate any increase in mineralisation for two winters after the minimally cultivated plots were ploughed in autumn 1990, probably because the soil was then very dry. This increase was apparently delayed until the fifth winter (1992/1993), which was much wetter than any since autumn 1990. In the previous eight years (1980–1988) half of the plots had been ploughed and half had been direct drilled. Averaged over the five winters 1988/1989–1992/1993, the five measures of nitrate loss in drainflow from plots previously direct drilled were 6–57% more than from plots previously ploughed, and winter mineralisation was 20% more, with no evidence of any decline in either with time. The nitrate produced by mineralisation of organic matter conserved by the eight years of direct drilling was mainly lost by leaching or denitrification; it was of little or no benefit to the crops. The results suggest that in the long term more nitrate is leached from land subject to periods of minimal or zero tillage and ploughing than from land ploughed every year.     

煤矿锚杆孔钻进设备技术问题分析

锚杆孔钻进设备是矿山和矿井开采的重要机械设备。在煤矿实际应用中，回转式锚杆钻机扭矩偏低，产品可靠性差。应采取改进设计，提高制造质量和加强施工管理等多措施延长锚杆孔钻使用寿命.     

MDT6.0与INVENTOR9巧妙结合进行动力头虚拟设计

阐述了虚拟设计技术的基本理论,介绍了MDT6.0与INVENTOR9两种三维设计软件在旋挖钻动力头设计中的应用,论述了两种软件建模及巧妙结合的过程。     

Nitrogen Dynamics and Losses in Direct‐Drilled Maize Systems

Abstract

The knowledge of nitrogen (N) losses in direct‐drilling agrosystems is essential to develop strategies to increase fertilizer efficiency and to minimize environmental damage. The objectives were i) to quantify the magnitude of N volatilization and leaching simultaneously as affected by different urea fertilization rates and ii) to evaluate the capacity of these specific plant–soil systems to act as a buffer to prevent nitrate leaching. Two experiments were conducted during 2001/02 and 2002/03 growing seasons in Alberti, Argentina. The crop was direct‐drilled maize and the soil a Typic Argiudoll. Ammonia losses, N uptake by crop at flowering and harvest, grain yield, N in previous crop residues, and soil nitrate content up to 2‐m depths were determined. Nitrogen availability, soil nitrate (NO₃)‐N up to 1 m plus fertilizer N, was linearly and highly associated with crop N uptake at flowering (R²=0.93, P<0.01) and at harvest (R²=0.852, P<0.01). Around 17.5% of fertilizer N was lost by volatilization in 10 days. The obtained values of residual nitrate N up to the 150‐cm depth were associated (R²=0.960, P<0.001) with those predicted by the nitrate leaching and economic analysis package (NLEAP) model. Maize in the direct‐drilling system was able to cycle N from the previous crop residues, N from soil organic matter, and N from fertilizers with few losses.     

寒地水稻新基质稀条播育秧技术研究

通过对水稻育秧新基质的容重、孔隙度、酸碱性、组成成分、透气性、保水性及其在水稻稀条播育秧上的应用情况研究,结果表明:以珍珠岩、蛭石、草炭为主要组成的育秧基质在传统育秧及条播育秧上对提高秧苗的综合素质起到了明显的促进作用。     

不同施氮比例对直播水稻产量的影响

为了探讨精量机条播和人工撒播水稻产量形成的规律,明确直播稻最适宜的氮肥运筹比例,特做了不同前后氮肥比例对精量机条播和人工撒播水稻产量的影响。试验结果表明:机条播的最优氮肥运筹比例为7∶3,人工撒播的最优氮肥运筹比例为6∶4;精量机条播比人工撒播产量高的主要优势在于有效穗不减少,而穗型变大;后期氮肥比例增加促进二次枝梗的数量,提高每穗总粒数和每穗实粒数;适宜的氮肥运筹比例能明显促进抽穗期、成熟期的干物质积累量。     

三轮汽车和低速货车右支撑管5孔钻模及夹具体设计

针对右支撑管上的5孔钻孔加工进行了钻模的形式及尺寸设计,同时设计出钻孔过程中定位所需的专用定位元件,选择了各定位元件的最佳形式及尺寸,并设计出加工过程所需的专用夹具。在对零件技术要求严格分析的基础上,在理论上设计出一套安装方便、制造经济可行的专用钻夹具。