锡林浩特地区太阳紫外辐射分析

为进一步揭示紫外辐射的变化规律,更好地为生产和人们的生活服务,基于锡林浩特国家气候观象台2007—2012年太阳紫外辐射观测资料,运用数理统计学方法与SPSS 11.5软件,分析了锡林浩特地区不同云况条件下太阳紫外辐射规律及与气象要素的相互关系。结果表明:太阳紫外辐射存在明显的日、季、年变化规律。一日内早晚小,中午大。一年内最高值出现在6—8月,最低值出现在11—12月。且与太阳总辐射、光合有效辐射、空气温度、空气湿度、地温0~5 cm存在较显著的相关性。目前锡林浩特地区紫外辐射强度(UV-B)1—3、10—12月最大值范围分别为0.20~1.91、0.13~1.43 W/m~2,低于人和动物的安全标准2 W/m~2,4—9月可出现最大值范围为2.02~3.39 W/m~2,容易对人和动物造成威胁和伤害。     

宿迁市宿城地区半地下土墙日光温室的生产现状 问题与对策

对宿迁市宿城区半地下土墙日光温室基地的生产现状进行了详细了解,并分析了其发展优势和存在的隐患,进一步提出了相应的发展对策。     

Selenium supplementation improves nutrient intake and digestibility,and mitigates CH4 emissions from sheep grazed on the mixed pasture of alfalfa and tall fescue

Low selenium (Se) in soil and forage can adversely affect on the quality of animal-derived foods, and hence on human health. Lambs grazed on mixed pastures of alfalfa (Medicago sativa) and tall fescue (Festuca arundinacea) were supplemented with five levels of Se [0, 3, 6, 9 and 12 µg/kg body weight (BW)]. The intake of dry matter (DM) and organic matter (OM) varied with the level of Se supplementation, with a peak at 6 µg Se per kg BW (p ≤ 0.05). Gross energy (GE) intake, digestive energy (DE) intake and metabolic energy (ME) intake were higher at 6 µg Se per kg BW than at other Se levels (p < 0.01); in addition, methane energy (CH₄-E) output was lower at 6 µg Se per kg BW. Supplementation with Se significantly increased nitrogen (N) intake, faecal N and urine N, for which the peak values were 20.2 g N/, 5.62 g N/day and 7.92 g N/day, respectively, at 6 µg Se per kg BW. Se intake, blood Se, faecal Se, urine Se and retained Se were negatively correlated with forage crude protein (CP) content (p < 0.001) but were positively correlated with the content of neutral detergent fibre (NDF) (p < 0.001) and acid detergent fibre (ADF) (p < 0.001). Thus, we recommend the addition of 6 µg Se per kg BW to sheep grazed on pastures in regions with low soil Se.     

Effects of thermal energy on extrusion characteristics,digestibility and palatability of a dry pet food for cats

The influence of specific thermal energy (STE) applications on extruder preconditioner was evaluated in a dry food for cats. In the first study, six STE applications were tested with mass temperatures of 45°C, 55°C, 65°C, 75°C, 85°C and 95°C. The extrusion parameters, starch gelatinization and kibble formation were evaluated. Diets were given to cats to evaluate digestibility, faecal characteristics and palatability. In the second experiment, three treatments were compared: low STE—a preconditioner temperature of 45°C (_LSTE); high STE—a preconditioner temperature of 95°C (_HSTE); high STE (preconditioner temperature of 95°C) combined with an increase in the mass flow rate to obtain a motor amperage similar to that of the _LSTE (_HSTE_flow). Data were analysed by polynomial contrasts (Experiment 1) or Tukey's test (Experiment 2; p < 0.05). An increase in STE reduced motor amperage, mass pressure and specific mechanical energy (SME) implementation (p < 0.001) and increased total specific energy (TSE) and mass temperature (p < 0.01). The increase in STE induced greater kibble expansion and starch gelatinization (p < 0.001). No changes in apparent nutrient digestibility or faeces characteristics were observed (p > 0.05). Lower STE and starch gelatinization induced higher butyrate and total volatile fatty acid (VFA) contents in faeces (p < 0.01). Cats showed greatest preference for the formulation with the highest STE (p < 0.01). In the second experiment, when the motor amperage was increased in the _HSTE_flow treatment to a value similar to that of the _LSTE, the mass flow rate increased 40%, and the electric energy consumption remained unchanged (p < 0.001), with gains observed for efficiency and cost. In conclusion, STE application is important for sufficient TSE implementation, enhancing kibble expansion, starch gelatinization, cat preferences for food, extruder productivity and reducing SME application. Foods with lower starch gelatinization lead to increased VFA in faeces, with possible implications for gut health.     

不同净能水平日粮对育肥猪生长性能、背膘厚度及眼肌面积的影响

试验研究不同净能水平日粮对育肥猪生长、背膘及眼肌面积的影响。选择420头(38.5±0.5)kg丹系三元育肥猪,随机分为5组,每组6个重复,每个重复14头猪,公、母各半。试验A、B、C、D、E组饲粮净能水平分别为9.84、10.05、10.26、10.46和10.67 MJ/kg,预试期7 d,正式试验期97 d。结果显示,A组育肥猪0~97 d的平均日采食量显著高于E组(P<0.05)。A组、B组育肥猪0~97 d的料重比显著高于D组、E组(P<0.05),且A组显著高于C组(P<0.05)。A组均重110 kg育肥猪的眼肌面积显著高于E组(P<0.05)。A组、B组均重130 kg育肥猪的眼肌面积显著高于E组(P<0.05)。A组均重110 kg育肥猪的背膘厚度显著低于D组、E组(P<0.05)。A组130 kg育肥猪的背膘显著低于D组、E组(P<0.05)。试验表明,净能为9.84 MJ/kg日粮可以明显提高平均日采食量、眼肌面积,并且降低背膘厚度。     

日粮蛋白质水平对云南半细毛羊空怀母羊能量代谢的影响

为研究日粮蛋白质水平对云南半细毛羊空怀母羊能量代谢的影响,试验选择25只云南半细毛羊空怀母羊,平均分为5个组,分别饲喂蛋白质水平为8.4%、10.0%、12.3%、13.6%、15.9%的日粮,用全收粪法进行消化代谢试验,试验期共19 d,预试期14 d,正试期5 d。结果表明：（1）日粮蛋白质水平对总能摄入量无显著影响（P > 0.05）。（2）从组1到组5粪能逐渐下降,且组3、组4、组5较组1分别降低了10.5%、11.4%、13.7%（P < 0.05）,组5较组2降低了9.5%（P < 0.05）。（3）从组1到组5尿能逐渐增加,除组2与组1、组3间差异不显著（P > 0.05）外,其余组间差异极显著（P < 0.01）。（4）组4和组5总能消化率较组1极显著提高13.2%和11.8%（P < 0.01）,其余各组差异不显著（P > 0.05）。组4总能代谢率较组1极显著提高9.8%（P < 0.01）,其余各组差异不显著（P > 0.05）。对于消化能代谢率,组1和组2差异不显著（P > 0.05）,组3、组4和组5依次显著降低（P < 0.05）。（5）蛋白质采食量与总能消化率、消化能代谢率间的回归方程分别为：Y=0.917X+45.872（R2=0.853）|Y=-0.370X+87.735（R2=0.899）。综上,日粮蛋白质水平与粪能呈负相关,与尿能呈正相关。日粮蛋白质水平为13.6%时,总能消化率和总能代谢率均较8.4%蛋白质水平组极显著提高。总能消化率随蛋白质采食量的提高而线性升高,消化能代谢率则随蛋白质采食量的提高而线性降低。 [关键词] 蛋白质|云南半细毛羊|空怀期|能量代谢     

高产棉花太阳辐射能利用率及干物质分配规律研究

通过对1988～1989年高产棉花栽培试验结果进行分析发现,棉花的太阳辐射利用率在叶面积系数小于2.0时随叶面积系数的增加而线性增加,大于2.0时增加变缓。从生育时间看,7月中旬前太阳辐射利用率指数上升,7月中旬至8月底相对稳定在1.2～1.4克/兆焦左右,9月以后又不同程度线性下降。生长季内子棉太阳辐射经济效率1988和1989年分别为0.14和0.15克/兆焦。收获指数与最大叶面积系数呈显著负相关;盛花期之前棉株各器官之间的同伸关系或明显,盛花期后器官的生长相互间无明显的确定性关系。如能调节密度与叶面积系数的关系,使得既提高5～6月的辐射能利用率,同时使7～8月叶面积系数维持在3.0～3.5的适宜范围内,9～10月群体又不早衰,则有利于获得高产。     

我国柴油轿车的发展现状及展望

随着汽车工业的不断发展，轿车动力柴油化已成为行业发展的必然。总结了我国柴油轿车的发展现状，指出了柴油轿车的优势，论述了制约柴油轿车发展的因素，提出了促进柴油轿车未来发展的几点建议。     

基于热力学定律的太阳能利用探究

本文对太阳能的起源、传播、与物质的相互作用以及储存和利用等各个方面所涉及的物理学定律,特别是对太阳能热利用所涉及的热力学定律进行了概括和归纳。根据热力学定律指出太阳能热利用的真正适用范围。     

山西省大面积推广北方能源生态模式技术的思考

北方能源生态模式是一项高效的生态农业技术。该技术在山西省已推广近667 hm²(万亩)，经济、能源、生态环境和社会等综合效益十分显著。但是，现在的推广速度远远不能满足农业生产发展的需要。面对国内外农产品市场激烈竞争和我省生态环境脆弱及农民收入增长缓慢的严峻形势，迫切需要大面积推广这一技术。因此，针对推广中存在的问题，应采取加强宣传、扩大规模，典型引路、整体推进，多方集资、加大投入，扩大队伍、强化服务，加强技术培训，市场化引导、产业化发展等相应对策，大力推广这一技术。