农村公路投融资现状及对策探讨

我国农村公路投融资的现状和存在的问题,分析了常用公路融资模式对农村公路的不适用性,结合我国的国情和农村公路建设的特点,提出了发行农村公路建设债券、建立农村公路专项资金、国家优惠政策和市场化运作等方面以拓宽农村公路融资渠道。     

续断菊与蚕豆间作下土壤部分化学特征与Cd形态分布状况研究

通过田间试验,研究间作和单作两种种植模式下植物根际土壤p H、有机质、碱解氮、速效钾、速效磷和不同形态Cd分布状况变化,考察综合因素对土壤重金属Cd形态分布状况与续断菊(Sonchus asper L.Hill)和蚕豆(Vicia faba L.)两种植物吸收Cd的影响。结果表明:随着植物的生长,单作蚕豆与单作续断菊土壤p H值没有显著变化,间作土壤p H值下降0.11个单位;间作土壤有机质比单作蚕豆和单作续断菊分别增加12.64%和20.13%;随着植物的生长,间作与单作蚕豆碱解氮含量分别显著增加139.87%、155.15%;间作与单作续断菊土壤速效钾含量接近,变幅在5%左右,单作蚕豆下降10.60%;不同种植模式土壤速效磷含量均呈现下降趋势,间作显著下降7%左右,单作蚕豆与续断菊下降量接近;各时期Cd各形态含量分布为可交换态碳酸盐结合态铁锰氧化物结合态有机物结合态;成熟期间作Cd可交换态含量比单作蚕豆与单作续断菊分别下降21.98%、22.13%,碳酸盐结合态、铁锰氧化物结合态和有机物结合态含量没有差异性;间作蚕豆生物量相比单作降低了24.77%,间作续断菊生物量相比单作增加15.29%;单作蚕豆根、叶、豆荚与籽粒Cd质量分数显著大于间作蚕豆,间作续断菊地上部Cd质量分数显著大于单作,根部无差异。总之,间作增强了续断菊对Cd的吸收,降低了蚕豆对Cd的吸收。     

广金钱草商品规格等级相关文献考证

[目的]梳理出广金钱草商品规格等级方面相关的指标。[方法]查阅有广金钱草记载的历代本草、近代专著以及国家、行业和地方各标准,从名称、基原、产地变迁、品质评价等方面对广金钱草进行文献考证,从国家、行业和地方各标准所规定的基原、性状、质控等进行现有标准汇总,对已有规格等级划分标准进行总结。[结果]广金钱草历代本草记载与现代记载的来源基本一致,主产于广东、广西及海南,品质"以叶多、色绿者为佳"为最优评优指标,地方标准与《中国药典》中记载的广金钱草的来源、性状、质控指标基本一致,其商品规格目前只有"统货"这一规格。[结论]该研究为广金钱草商品规格等级标准的制定奠定基础。     

滇西北高原湖泊剑湖流域景观时空演变特征

为深入了解流域景观演变规律并有效保护高原湖泊,以滇西北剑湖流域为研究对象,基于1990-2015年6期剑湖流域以及1974-2015年8期剑湖湖泊Landsat影像数据,在Arc GIS平台下采用Fragstats计算景观指数,并运用SPSS分析流域景观格局与剑湖景观形状的相关性。结果表明:①25 a间剑湖流域的建设用地和耕地呈增加趋势,分别增加了1 269.27和1 038.42 hm2,水域和未利用地显著减少,分别减少了93.51和2 664.99 hm2,林地面积变化幅度不大,增加了450.81 hm2;②景观水平斑块个数、斑块密度和蔓延度指数增加,分别增加了193个、0.09和0.60,景观多样性指数降低了0.05;③剑湖湖泊面积整体呈递减趋势,从1974年的504.47 hm2减少到2015年的451.72 hm2;剑湖景观形状指数越来越复杂,金龙河入湖口形状变化尤其剧烈;剑湖湖泊质心向西南偏移,1974-2015年偏移了113.92 m。表明:剑湖流域25 a间景观破碎化程度和景观蔓延度不断增加,泥沙淤积、围湖造田等人类活动对剑湖景观的演变起主要作用,流域景观格局的演变影响湖泊形状及质心的变化。     

Response of soil Olsen-P to P budget under different long-term fertilization treatments in a fluvo-aquic soil

The concentration of soil Olsen-P is rapidly increasing in many parts of China, where P budget(P input minus P output) is the main factor influencing soil Olsen-P. Understanding the relationship between soil Olsen-P and P budget is useful in estimating soil Olsen-P content and conducting P management strategies. To address this, a long-term experiment(1991–2011) was performed on a fluvo-aquic soil in Beijing, China, where seven fertilization treatments were used to study the response of soil Olsen-P to P budget. The results showed that the relationship between the decrease in soil Olsen-P and P deficit could be simulated by a simple linear model. In treatments without P fertilization(CK, N, and NK), soil Olsen-P decreased by 2.4, 1.9, and 1.4 mg kg~(–1) for every 100 kg ha~(–1) of P deficit, respectively. Under conditions of P addition, the relationship between the increase in soil Olsen-P and P surplus could be divided into two stages. When P surplus was lower than the range of 729–884 kg ha~(–1), soil Olsen-P fluctuated over the course of the experimental period with chemical fertilizers(NP and NPK), and increased by 5.0 and 2.0 mg kg~(–1), respectively, when treated with chemical fertilizers combined with manure(NPKM and 1.5 NPKM) for every 100 kg ha~(–1) of P surplus. When P surplus was higher than the range of 729–884 kg ha~(–1), soil Olsen-P increased by 49.0 and 37.0 mg kg~(–1) in NPKM and 1.5 NPKM treatments, respectively, for every 100 kg ha~(–1) P surplus. The relationship between the increase in soil Olsen-P and P surplus could be simulated by two-segment linear models. The cumulative P budget at the turning point was defined as the "storage threshold" of a fluvo-aquic soil in Beijing, and the storage thresholds under NPKM and 1.5 NPKM were 729 and 884 kg ha~(–1)P for more adsorption sites. According to the critical soil P values(CPVs) and the relationship between soil Olsen-P and P budget, the quantity of P fertilizers for winter wheat could be increased and that of summer maize could be decreased based on the results of treatments in chemical fertilization. Additionally, when chemical fertilizers are combined with manures(NPKM and 1.5 NPKM), it could take approximately 9–11 years for soil Olsen-P to decrease to the critical soil P values of crops grown in the absence of P fertilizer.     

Regulation of Calcium on Peanut Photosynthesis Under Low Night Temperature Stress

The effects of different levels of CaCl 2 on photosynthesis under low night temperature（8°C） stress in peanuts were studied in order to find out the appropriate concentration of Ca2＋through the artificial climate chamber potted culture test.The results indicated that Ca2＋,by means of improving the stomatal conductivity of peanut leaves under low night temperature stress,may mitigate the decline of photosynthetic rate in the peanut leaves.The regulation with 15 mmol L-1CaCl 2（Ca15） was the most effective,compared with other treatments.Subsequently,the improvement of Ca2＋on peanut photosynthesis under low night temperature stress was validated further through spraying with Ca15,Ca2＋chelator（ethylene glycol bis（2-aminoethyl） tetraacetic acid; EGTA） and calmodulin antagonists（trifluonerazine; TFP）.And CaM（Ca2＋-modulin） played an important role in the nutritional signal transduction for Ca2＋mitigating photosynthesis limitations in peanuts under low night temperature stress.     

侵蚀果园长期植草的生态效益分析

针对山地果园不合理开发引发的土壤侵蚀和土壤退化问题,将适生牧草套种于幼龄侵蚀果园,开展水土流失、土壤肥力及果树生长的定位观测。结果表明:套种平托花生(Arachis pintoi)、圆叶决明(Chamaecrista rotundifolia)1～12年,年地面径流系数0～0.0136,均值为0.007左右,仅为清耕处理的1/10,基本无土壤侵蚀发生;套种11年,套种区0～30 cm土层的土壤pH值比清耕分别提高0.25～0.30个单位,0～15 cm土层土壤有机碳、碱解氮、有效磷质量分数比清耕提高7.595～6.728 g·kg^-1,26.84～31.89 mg·kg^-1,3.57～4.62 mg·kg^-1;轻组有机碳质量分数在0～30 cm土层呈套种平托花生>套种圆叶决明>清耕的变化趋势,重组有机碳质量分数在0～15cm土层亦呈相同变化趋势。套种处理有助改善果肉糖酸比和商品果率,牧草综合利用可明显提升果园建园初期的经济效益,尽管套种处理给果树带来一定的减产。     

兔球虫病药物防治研究进展

兔球虫病是严重危害养兔业发展的寄生虫病之一。长期以来,兔球虫病主要依靠化学药物和中草药等进行防治,由于球虫极易产生耐药性,给药物防治带来了困难。论文从兔球虫生物学特性、防治兔球虫病的药物等方面做一综述。     

安徽部分地区冬春季仔猪腹泻的流行病学调查与分析

2012年1-3月间,通过定点监测、问卷调查、实地调查和实验室检测等方式,对安徽省16个市、50个县的757个养猪场(户)的仔猪腹泻发病情况进行了流行病学调查,并采集74份发病或病死仔猪样品肠内容物进行实验室检测.结果表明,安徽省仔猪腹泻主要以流行性腹泻、猪传染性胃肠炎为主,其中猪流行性腹泻病毒阳性率为89.2％,猪传染性胃肠炎病毒样阳性率为10.8％,饲养管理条件差和环境气候多变等是冬春季仔猪腹泻多发的重要诱因.     

不同乳酸菌添加量和发酵时间对全株玉米青贮营养价值及发酵品质的影响

本试验以登海605玉米品种为材料,于蜡熟期2/3乳线时进行刈割,乳酸菌制剂的添加量分别为0,10,20和30 mg·kg^-1,4个处理,每个处理4个重复,在室温条件下发酵45和90 d,取样测定营养成分、发酵品质和瘤胃降解率等指标,旨在研究不同乳酸菌添加量和发酵时间对全株玉米青贮营养价值的影响。结果表明:干物质(DM)受乳酸菌添加量和发酵时间的影响较小,差异不显著(P>0.05);随乳酸菌添加量的增加,发酵90 d的中性洗涤纤维(NDF)含量显著线性降低(P=0.018),而相对饲喂价值(RFV)显著线性增加(P=0.006)。发酵90 d的酸性洗涤纤维(ADF)含量和pH值较45 d显著降低(P<0.01),而乳酸和乙酸含量显著增加(P<0.05)。随乳酸菌添加量的增加,乳酸含量显著线性增加(P<0.05)。24 h的DM和NDF消化率受乳酸菌添加量和发酵时间的影响较小,差异不显著(P>0.05)。发酵90 d时,48 h DM降解率随乳酸菌添加量的增加显著线性增加(P=0.034),48 h NDF降解率较45 d显著增加(P=0.022)。发酵90 d时,20 mg·kg^-1组的RFV、总可消化养分(TDN)和有机酸含量最高,而pH值最低。综上所述,乳酸菌添加量和发酵时间对全株玉米青贮的营养成分含量、发酵品质和DM瘤胃降解率均有显著影响,全株玉米青贮在发酵90 d且乳酸菌添加量为20 mg·kg^-1的营养价值和发酵品质最优。