地形对漫川漫岗黑土区大豆产量的影响

为研究黑土区田块尺度地形对大豆产量造成的影响,在海伦东兴合作社具有明显地形起伏的地块,采集大豆田间试验数据,考虑温度、太阳辐射、坡度、土壤养分等因素,运用作物生长模型DSSAT(Decision Support Systemfor Agrotechnology Transfer)模型对各样点进行参数率定及验证,得出以下结论:1)DSSAT模型的模拟产量与实际产量的相对均方根误差为7.9%,模拟结果表现为优,表明运用作物模型模拟不同地形上的产量变异具有可行性;2)地形通过影响作物生长环境因子的时空差异决定产量差异,田块尺度温度、水分和坡度是影响产量差异的主要因素;3)坡顶和坡底的产量相对较高,且产量变异性较小,阳坡虽然接收到更多的光照,却由于水分胁迫造成减产,坡底和平缓坡顶水肥保持较好,易获得高产。研究成果为田间精细管理与田块尺度耕地高效利用提供科学依据。     

Screening and Identification of the antagonistic strain DL-59 of B. velezensis against A. brassicae and biocontrol efficiency

The aim of this study was to screen the antagonistic spore-forming bacteria of Alternaria brassicae and to assess their control effect. The test microorganism was A. brassicae in this experiment. One spore-forming strain named DL-59 with a rather stronger antagonistic activity than ever reported was obtained by using an improved agar plate diffusion method. Morphological, physiological and biochemical tests combined with 16S rDNA sequence analysis were carried out to identify DL-59. Its control effect was studied in the basin culture and the plot trials. Two hundred strains were isolated form soil and 20 antagonistic bacteria strains were obtained through preliminary screen. After the secondary screening, a strain named DL-59 with a rather stronger antagonistic activity was obtained and identified as B. velezensis with the largest diameter of inhibition zone of 23 mm. The control efficacy was 79.07%. The plot trials showed that DL-59 had a visible preventive effect on cabbage black spot disease. This can be applied for biological control of plant disease. The strain can produce spores, which is important for the storage of its preparation.     

农地征收中的产权弱化问题分析

基于产权理论角度分析中国农地征收中存在的产权弱化问题。经过分析发现,农地产权的弱化导致农地征收的租值消散问题、农地征收定价困难问题与农地产权保护薄弱问题,这些问题都是造成农地征收补偿矛盾的重要原因。因此,中国农地征收可以从建立农地使用权交易市场、建立第三方评估制度、转变政府职能、加强农地产权保护等方面进行农地征收的制度完善,以强化农地产权,解决征地补偿中出现的诸多矛盾和问题。     

MYB转录因子在植物耐盐基因工程中的应用进展

盐胁迫是影响植物生长、发育及作物产量的重要环境因子。耐盐育种是保障农业生产的重要措施,利用基因工程技术提高植物耐盐性是优于传统育种的有效途径。MYB转录因子是植物中最大的转录因子家族之一,在包括盐胁迫在内的植物非生物胁迫调控中有重要作用。本文系统阐述了MYB转录因子的基本结构及其在拟南芥、烟草及水稻、大豆、番茄等植物耐盐基因工程中应用的研究进展,为MYB转录因子的利用及植物耐盐遗传改良及育种提供参考。     

基于RNA-seq的谷子萌芽期抗旱相关基因挖掘与分析

为了明确响应干旱胁迫的关键基因,解析谷子抗旱机制,本研究以谷子抗旱品种山西2010和干旱敏感品种K359*M4-1为材料,应用RNA-seq技术对两个品种干旱胁迫前后萌发期种子进行转录组测定。结果表明,在山西2010和K359*M4-1中分别鉴定出2 300个和3 652个差异表达基因(DEG),包括编码类锌诱导的促进因子、类萌发素蛋白、蛋白磷酸化酶、转运蛋白、胚胎发育晚期丰富蛋白(LEA)、转录因子、过氧化物酶等基因。通过对鉴定到的DEG进行GO和KEGG代谢途径富集分析,发现山西2010和K359*M4-1中的DEG分别富集在52个和21个生物学过程。KEGG 富集分析发现,DEG主要富集在淀粉和蔗糖代谢, 植物激素信号转导,光合作用-天线蛋白,苯丙素生物合成,角质、亚氨酸和蜡生物合成,次生代谢物生物合成等途径。本研究结果为挖掘谷子抗旱关键基因、解析谷子抗旱机制奠定了基础。     

基于动力学的Stewart平台振动控制策略研究

针对利用基于运动学控制方法的大负载、高质心Stewart平台实现某一姿态下的单自由度正弦振动时将引起其他自由度上的耦合振动问题,提出了一种在位置闭环控制条件下基于动力学的振动控制策略。该控制策略利用动力学模型所计算的各液压缸出力控制平台振动,提高了控制精度。最后利用Stewart平台在15°俯仰姿态下对该方法进行了实验验证,通过比较运动学和动力学两种控制方法的振动响应,表明提出的控制方法能够有效抑制由负载引起的耦合振动,实现了Stewart平台在任意姿态下的精确振动控制。     

阜平县不同海拔梯度下耕地土壤养分现状与分布特征

为在太行山区阜平县对耕地土壤提出科学合理的施肥理论依据,利用2018年阜平县耕地测土配方施肥调查数据,运用统计学和克里金插值方法研究了阜平县耕层土壤有机质、碱解氮、有效磷、速效钾及pH等养分含量现状及分布特征。结果表明:当前阜平县耕地土壤pH、有机质、碱解氮、有效磷和速效钾的均值含量分别为7.08,21.84 g/kg, 70.53 mg/kg, 22.43 mg/kg, 75.43 mg/kg,土壤pH值主要为中性水平,占比65.42%;土壤有机质含量、碱解氮含量和速效钾含量均表现为以中等含量水平为主,占比分别为45.55%,43.19%和59.86%,处于中等及以上的占比分别为98.76%,64.42%和75.96%;土壤有效磷含量主要处于高等含量水平,占比29.99%,而高等及以上水平占比74.15%。从空间分布上耕地土壤有机质、碱解氮、有效磷和速效钾大体均呈现由东南向西北逐渐增长的趋势,而从海拔梯度分区下有机质和有效磷呈现丘陵区(21.85 g/kg)<低山区(21.92 g/kg)<中山区(22.70 g/kg)趋势,碱解氮呈现中山区(64.72 mg/kg)&l...     

Relationship between nitrous oxide emission and winter wheat production

A 3-year field study in southeast China was performed to examine the relationship between N₂O emission and winter wheat production. Over the 2002–03, 2003–04 and 2004–05 wheat-cropping seasons, N₂O emissions depended on nitrogen addition, plowing practice, and preceding crop type treatments, and showed a pronounced inter-annual variation. N₂O–N emission factor, the proportion of fertilizer N released as N₂O–N from the wheat field, varied from 1.33% to 2.97%. The relationship between N₂O emission (y) and crop yield (x) was well explained by the function y = 3.773Ln(x) + 1.46. Similarly, the function y = 4.445Ln(x) − 3.52 can be employed to address the relationship between N₂O emission (y) and above ground biomass (x). About 84% and 87% of variation in seasonal N₂O emission were explained by the two functions, while only 66% of the variation was represented by the N input with a linear relationship. The results of this study suggest that seasonal N₂O emission of soil under winter wheat could be better predicted by crop yield and biomass than by N input. Submitted to Biology and Fertility of Soils.     

混合动力汽车电机最优工作曲线确定与应用

在并联混合动力汽车最优工作曲线控制策略的研究中,都是以发动机为主控对象,令其工作在最优曲线上以提高整车的燃油经济性,但电机在工作中的效率并不一定是最佳的.以混合动力汽车另一个动力提供源--电机为主控对象,通过找寻电机最佳效率工作曲线,制定相应的电机最优工作曲线控制策略.与逻辑门限值控制策略的仿真进行对比,结果表明电机最优工作曲线控制策略可以使整车百公里燃油消耗量降低9.5%,电机平均工作效率提高23%.     

对动物疫病防治体制改革的几点设想

随着改革开放步伐加快，全球经济一体化逐步形成，我国与国际动物疫病防治体制的接轨已势在必行，我国的动物疫病防治体制将面临新的挑战，对现行的动物疫病防治进行改革和完善，已迫在眉睫。