近50年唐山地区初终霜日、无霜期变化特征分析

利用唐山11个站的气象观测资料,详细分析了我市近50年来的霜的分布特征和变化趋势,结果表明：我市霜的分布具有明显的地域特征,无霜期南北相差约30天;我市初霜日明显延后,气候倾向率达到1.22天/10年;终霜日略有提前,但是不明显,气候倾向率只有0.836天/10年,主要受初霜日延后的影响,我市无霜期明显增加,气候倾向率为2.18天/10年;我市初终霜、无霜期年代特征明显;经突变分析,我市初终霜、无霜期存在明显的转折年。     

河西走廊东部大风日数时空分布及其对沙尘天气的影响

为揭示大风日数的时空演变规律及其对沙尘天气的影响,更好地防御和减轻风沙灾害。笔者利用1971—2010年河西走廊东部4个气象站大风、沙尘暴、扬沙观测资料,采用气候统计学方法,对河西走廊东部大风日数时空演变及与沙尘暴和扬沙日数的关系进行分析。结果表明:近40年河西走廊东部年大风日数以10.77 d/10 a的速率显著减少;四季年大风日数亦均呈显著减少,递减率夏季最大,冬季最小;年、季节大风日数随年代增加呈减少趋势;大风日数春季最多,秋季最少,4月最多,9月最少。大风日数的空间分布与海拔高度、地形地貌有很大关系,高海拔山区大风日数最多,北部荒漠区以及浅山区较多,绿洲平原区最少。近40年河西走廊东部年沙尘暴和扬沙日数均显著减少。年大风日数与年沙尘暴和扬沙日数呈极显著正相关,其相关系数分别为0.878和0.888;大风日数随时间的变化对沙尘日数随时间的变化具有显著正作用,大风日数的减少可能是沙尘日数减少的主要原因之一。     

水稻抽穗期基因定位及其环境互作研究

为构建SSR分子标记技术构建其遗传图谱,利用由小穗小粒型品种‘密阳46’和大穗大粒型品种FJCD建立的一个包含130个家系F10的重组自交系群体,测定武夷山和莆田环境下水稻群体的抽穗期,并进行了QTL的定位及环境互作研究。结果表明,在武夷山环境下仅检测到一个与抽穗期相关的加性QTL,位于6号染色体上,解释了25.63%;1个位点存在显著的加性×环境互作效应,而GE互作效应对表型变异贡献几乎为0,表明控制水稻抽穗期基因的表达有显著的环境特异性。     

Tomato nitrogen accumulation and fertilizer use efficiency on a sandy soil, as affected by nitrogen rate and irrigation scheduling

Tomato production systems in Florida are typically intensively managed with high inputs of fertilizer and irrigation and on sandy soils with low inherent water and nutrient retention capacities; potential nutrient leaching losses undermine the sustainability of such systems. The objectives of this 3-year field study were to evaluate the interaction between N-fertilizer rates and irrigation scheduling on crop N and P accumulation, N-fertilizer use efficiency (NUE) and NO₃-N leaching of tomato cultivated in a plastic mulched/drip irrigated production system in sandy soils. Experimental treatments were a factorial combination of three irrigation scheduling regimes and three N-rates (176, 220, and 330 kg ha⁻¹). Irrigation treatments included were: (1) surface drip irrigation (SUR) both the irrigation and fertigation line placed underneath the plastic mulch; (2) subsurface drip irrigation (SDI) where the irrigation drip was placed 0.15 m below the fertigation line which was located on top of the bed; and (3) TIME (conventional control) with the irrigation and fertigation lines placed as in SUR and irrigation applied once a day. Except for the TIME treatment all irrigation treatments were soil moisture sensor (SMS)-based with irrigation occurring at 10% volumetric water content. Five irrigation windows were scheduled daily and events were bypassed if the soil water content exceeded the established threshold. The use of SMS-based irrigation systems significantly reduced irrigation water use, volume percolated, and nitrate leaching. Based on soil electrical conductivity (EC) readings, there was no interaction between irrigation and N-rate treatments on the movement of fertilizer solutes. Total plant N accumulation for SUR and SDI was 12-37% higher than TIME. Plant P accumulation was not affected by either irrigation or N-rate treatments. The nitrogen use efficiency for SUR and SDI was on the order of 37-45%, 56-61%, and 61-68% for 2005, 2006 and 2007, respectively and significantly higher than for the conventional control system (TIME). Moreover, at the intermediate N-rate SUR and SDI systems reduced NO₃-N leaching to 5 and 35 kg ha⁻¹, while at the highest N-rate corresponding values were 7 and 56 kg N ha⁻¹. Use of N application rates above 220 kg ha⁻¹ did not result in fruit and/or shoot biomass nor N accumulation benefits, but substantially increased NO₃-N leaching for the control treatment, as detected by EC monitoring and by the lysimeters. It is concluded that appropriate use of SDI and/or sensor-based irrigation systems can sustain high yields while reducing irrigation application as well as reducing NO₃-N leaching in low water holding capacity soils.     

全日制专业学位研究生综合素质评价指标体系研究

结合全日制专业学位研究生的培养特点,依据一定的指标体系构建原则,运用层次分析法(AHP),在提出一套评价全日制专业学位研究生综合素质评价指标体系的基础上,对调查结果进行实证分析,并对评价结果进行说明,为科学、客观地评价全日制专业学位研究生综合素质提供了思路。     

3种扁谷盗对不同波长光趋性研究

【目的】研究锈赤扁谷盗Cryptolestes ferrugineus成虫、土耳其扁谷盗Cryptolestes turcicus和长角扁谷盗Cryptolestes pusillus雌成虫对不同波长光的趋性。【方法】室内应用光行为反应装置测试3种扁谷盗羽化1、11、21和31日龄(雌)成虫对试验波长303、320、330、340、351、368、400、445、460、480、520、525、545、560、575和580 nm的趋光率。【结果】锈赤扁谷盗羽化1、11、21和31日龄成虫趋光率最高的刺激光波长分别为351、351、400、480 nm,对锈赤扁谷盗成虫诱集效果较好的光波长有351、400和445 nm,随着日龄的增加,对锈赤扁谷盗成虫诱集率大于20%的光波数增加;土耳其扁谷盗羽化1、11、21和31日龄趋光率分别为16%~51%、11%~46%、7%~37%和4%~28%,雌成虫趋光率最高的刺激光波长分别为351(368)、368、330和351 nm,对土耳其扁谷盗雌成虫诱集效果较好的光波长有368、351和303 nm;长角扁谷盗羽化1、11、21和31日龄趋光率分别为1.11%~75.56%、18.89%~70.00%、33.33%~62.22%和22.22%~71.11%,雌成虫趋光率最高的刺激光波长分别为575、320、400(445)和320(560)nm,对长角扁谷盗雌成虫诱集效果较好的光波长有320、575和330 nm。【结论】锈赤扁谷盗成虫的趋光性随着日龄的增加而增强,土耳其扁谷盗雌成虫的趋光性随着日龄的增加而下降,长角扁谷盗雌成虫的趋光性随着日龄的增加略为下降。     

山东省新型农村合作医疗影响因素及满意度调查

采用问卷调查的方式,以山东省临清市金炉店村为例,运用SPSS模型的描述统计、假设检验、拟合优度等方法对农民参加新农合的影响因素以及满意度进行了实证分析。由调查结果可知影响农民参加的主要因素有:文化水平、身体状况等。影响农民满意度的主要因素有:宣传方式、报销比例、政府补贴。最后,本文针对调查中出现的问题提出合理化的建议。     

近50年西藏主要农区霜冻指标的变化特征

以最低气温≤0℃作为霜冻指标,利用西藏9个气象站点1961-2010年逐日最低气温资料,采用气候倾向率、累积距平、信噪比和R/S分析等统计方法,分析西藏主要农区初霜日、终霜日、无霜期和霜冻日的异常气候变化,以期提高对异常霜冻灾害的预测能力,为有效防御霜冻提供依据.结果表明,(1)近50a西藏主要农区部分站点具有初霜日推迟、终霜日提早、无霜期延长的趋势;所有站点的霜冻日均表现为显著的减少趋势,减幅为1.9 ～9.6d/10a(P ＜0.05).(2)20世纪80年代至21世纪初,大部农区表现为初霜日推迟、终霜日提早、无霜期延长和霜冻日减少的年代际变化特征,尤以21世纪初明显.(3)近50a来,主要农区特早初霜冻发生频数为1～5次,以波密最多;特晚终霜冻发生频数为1～6次,仍以波密最多且主要发生在60年代;特短无霜期发生频数为1～7次,以波密最高;特少霜冻日的发生频数为2～10次,主要在21世纪初;特多霜冻日的发生频数为1～7次,多发生在60年代.(4)突变检测表明,拉萨的霜冻日,泽当的终霜日、无霜期和霜冻日以及浪卡子的无霜期和霜冻日发生了气候突变,突变点分别在1992、1991和1998年.(5)根据R/S分析,大部农区终霜日的Hurst指数大于0.5,说明未来终霜日仍将趋于提早,以泽当最为突出;各农区霜冻日Hurst指数均大于0.5,表明未来霜冻日仍趋于减少.     

Antioxidation responses of maize roots and leaves to partial root-zone irrigation

Antioxidation responses of maize roots and leaves to water deficit and rewatering under partial root-zone irrigation (PRI) were investigated using a pot system. Plants were cultured using three irrigation methods, i.e. conventional irrigation (CI), alternate PRI (APRI) and fixed PRI (FPRI) with three different water regimes including W₁ (70% field capacity, FC), W₂ (50% FC) and W₃ (35% FC). Compared to CI, root peroxidases (POD) activity was enhanced in the irrigated root zone of FPRI and both root zones of APRI during mild water deficit. After rewatering, POD activity was increased in the dry root zone under FPRI but reduced in the roots under APRI. Roots in the dry zone and leaves under FPRI remained high superoxide dismutase (SOD) activity after rewatering. In contrast, SOD activity decreased in the roots and leaves under CI and APRI. Malondialdehyde (MDA) contents were increased in leaves and two sub-roots under FPRI during water deficit and remained higher after rewatering compared to those under CI and APRI. MDA contents in the tissues under APRI showed similar levels to those under CI. Compared to CI, APRI showed the same biomass production, achieving significantly higher water use efficiency under mild water deficit. The results suggested that plants under APRI experienced less oxidative stress or damage induced by water deficit.