杂交水稻制种提高结实率的研究

杂交水稻制种不同于水稻栽培、其结实由柱头外露结实和非柱头外露结实两部分构成；空壳中90％以上是由于没有授粉受精造成的：90％以上的受精拉都能正常发育结实。柱头外露率和受精率与结实率呈显著正相关。后期施肥、父本大龄秧和机械授粉能有效地提高柱头外露率、花遇优度和结实率及制种产量。     

黄土高原北部垄膜沟植田间集雨高效栽培技术研究

在黄土高原北部,采用起垄覆膜(垄上覆膜种植马铃薯,垄沟种植谷子)的垄沟间作田间集雨补灌栽培并结合增施氮、磷、钾化肥,具有显著的增产、增收效果。该技术可大大提高化肥的增产效果和肥料利用率,有明显的集雨增墒效果,同时采用起垄覆膜种植马铃薯与垄沟种植谷子能够合理利用有限的工程集雨,有利于充分利用有限的降水资源,进行节约化农业经营。     

Effects of arrangement of surge-rootirrigation emitters on growth,yield andwater use efficiency of apple trees

Six-year old apple trees were selected for field experiment. The objective of this study was to obtain the reasonable arrangement of surge-root irrigation emitters in apple orchards. There were three factors: the buried depth H( 25,40,55 cm),the horizontal distance L( 30,40,60 cm) between the emitters and the trunk of the experimental tree,and the number of the irrigation emitters N( 1,2,4). The effect of the arrangement of surge-root irrigation emitters on the growth,yield and irrigation water use efficiency( IWUE) of apple trees were studied in Northern Shaanxi where the irrigation quota takes 60%-75% of the field water capacity. The results showed that the arrangement of emitters for surge-root irrigation had a significant effect on apple tree yield and IWUE,especially,the yield and IWUE reached 28 388. 17 kg/hm2 and 16. 83 kg/m3 in treatment T3,respectively. At the same L and N levels( T1,T2,and T3),the yield and IWUE in treatment T3 were the highest,and the yields in treatments T1 and T2 were decreased by 26.22% and 31.48%,while IWUE is reduced by14.02% and 18.12% compared with T3,respectively. At the same H and N levels( T3,T4,and T5),the yield and IWUE of apple trees were decreased with increasing L level. Especially,when L was 30 cm( T3),the yield and IWUE were the highest. The same L and H levels( T3,T6,and T7) could promote the growth of apple trees when N was 2( T3). Compared with treatment T3,it was found that the increment of new shoots was decreased by 8.07%-18.71%,and the fruit diameter was decreased by 5.41%-9.11%. Therefore,two emitters should be arranged symmetrically on both sides of an apple tree,each was buried at a 40 cm depth and 30 cm away from the trunk of the tree to effectively improve the yield and IWUE of the apple tree in mountainous areas in Northern Shaanxi.     

射水成穴播种试验装置的设计及试验

提出了射水成穴播种的非接触播种新方法,设计并研制了自动射水成穴播种试验装置,通过土槽试验研究了射水成穴播种的可行性以及成穴的基本规律和合适的工作参数范围。成穴播种试验表明,在沙壤土条件下,当射水压力在1.8~2.0MPa、射水时间在0.6~1.0s时,可以实现射水成穴播种且能满足穴播的农艺要求。射水压力和射水时间对膜孔大小和穴孔深度有显著影响,射水压力和射水时间的交互作用也对膜孔大小和穴孔深度有显著影响。     

旋转式钵苗栽植机构多目标参数优化与试验

为了方便快捷地得到旋转式钵苗栽植机构的最佳参数,提出了旋转式钵苗栽植机构作业时实现理想栽植应满足的条件,包括栽植嘴运动学特性(轨迹、姿态、速度)、挖出穴口的几何特性、栽植机构避免干涉和非圆齿轮的保凸性要求。根据这些要求,以偏心-椭圆齿轮行星轮系栽植机构为研究对象,建立其11个子目标函数,并应用模糊理论,将多目标优化问题转化为单目标优化问题进行求解,得到满足理想栽植要求的参数,然后进行结构设计、虚拟仿真、试验台加工和模拟田间栽植试验,验证了该栽植机构的高立苗率和优化模型的正确性。该优化模型的建立和求解克服了栽植机构传统参数设计时采用仿真软件进行试凑的缺点,提高了优化效率。     

推广水稻机械化插秧现状及对策的研究——以武汉市新洲区为例

阐述了武汉市新洲区推广水稻机械化插秧的重要意义、现状、存在的主要问题,并提出了相应的建议。     

大豆新品种中黄30种植密度试验

为了探索大豆新品种中黄30在承德地区的最佳种植密度，试验采用回归设计法，设种植密度18.0万、22.5万、27.0万、33.8万、36.0万和45.0万株/hm 2计6个处理，对不同种植密度下的大豆病虫害发生情况和产量进行了分析；并对其种植密度与产量的关系进行了回归分析，建立了回归方程。结果表明：在试验设定的密度范围内，随着种植密度的增大，大豆虫食率、褐斑病率和紫斑病率均呈先降低后升高的变化趋势，其中密度为22.5万株/hm 2时，3种病虫害的发生率均最低，分别为0.4％、0.5％和0.1％；大豆产量呈先增加后降低的变化趋势，产量与种植密度的二次回归方程为 Y ＝-2731.4259＋358.9022 X-5.0335X 2。本研究条件下，密度为33.8万株/hm 2时大豆产量最高，为3801.667 kg/hm 2。     

Survival and Early Development of Lodgepole Pine

The effect of site fertility, spacing and mode of regeneration on the survival and stand development of lodgepole pine, Scots pine and Norway spruce was studied in a series of experiments comprising 22 study areas in Finland. After 13-14 yrs, lodgepole pine had a mean survival of 68% in planted and 61% in seeded plots, while Norway spruce had the highest (92%) and Scots pine the second highest survival (82%). The survival of planted lodgepole pine was better the wider the spacing. Best survival was achieved on subdry and dry sites, both with planting and with direct seeding. Dominant height was not affected by spacing, but both basal area and volume at the age of 13-14 yrs were significantly higher the denser the spacing. The average difference in the value of the estimated site index H ⁵⁰ was slightly under 3 m for the superiority of lodgepole compared with Scots pine. Seeding resulted in site indices almost as high as those of lodgepole planting.     

望江县易灾区种植业结构调整实例及其启示

望江县是一个以生产棉粮油为主的农业大县。近 10年来 ,夏季大小洪涝灾害平均 2年一遇 ,农业生产损失巨大 ,加之近年大宗农产品收购价格下调 ,种植传统的棉粮油作物效益下降。沿江棉区新农村针对农业生产面临的突出问题 ,调整种植结构 :棉地实行间作套种 ;压缩棉花面积 ,扩种玉米、豆类、蔬菜 ,科学安排茬口 ,规避夏季水灾 ;改低洼棉地种植莲藕 ,能有效地抗灾避灾增效。根据新农村的实践 ,笔者认为 :望江洲圩易灾区种植业结构调整 ,一要因地制宜 ,合理布局 ,科学安排茬口 ,以抗灾避灾 ;二要扩大特色作物种植面积 ;三要依靠科技提高效益 ;四要提供新型优质服务     

半荒漠地区灌木饲料林营造技术研究

本文对半荒漠地区灌木饲料林的树种选择、经营管理等问题进行了初步探讨，给出了花棒、杨柴、柠条、沙柳、毛条、毛柳、白沙蒿、油蒿８个半荒漠地区灌木饲料林树种的造林适宜立地类型、最适造林季节、最佳造林密度、最适收获期以及最佳平茬年龄。