碳酸氢钾与限制饲喂预防肉用鸡腹水症研究

将２４０只ＡＡ健康肉用鸡随机分为８组，饲养于两种不同温度下，通过饮水中添加碳酸氢钾和限制饲喂，观察肉用鸡腹水症发生情况，分别在２１天，２８天和３５天测定血氧饱和度，红细胞压积容量和血红蛋白等指标。试验结束时，每组扑杀８只肉用鸡，测定右心室和全心室重量之比。结果表明，寒冷可使腹水症发生率上升，明显高于对照组；与对照组相比，患腹水症肉用鸡的ＰＣＶ，Ｈｂ及ＲＴ／ＴＶ显著升高，而血氧饱和度显著。     

我国河流N_2O饱和度与释放系数变化及其与河流氮水平的关系研究

通过选择我国3个不同流域的河流,研究了河流N2O饱和度与释放量的时空变化及其与河流氮水平的关系,并评估了IPCC关于河流N2O的释放系数。结果显示,河流硝态氮和氨氮的浓度变化范围分别为0.023～5.24（均值1.29±0.822）mg N.L-1和0.020～40.3（均值2.54±5.47）mg N·L-1;相应地,河流N2O饱和度和释放量的变化范围分别为90%～8213%（均值407%±1010%）及0.250～1960（均值58.3±221）μg N.m-2·h-1。不同河流N2O饱和度均呈现明显的季节变化特征,N2O饱和度几乎持续处于过饱和状态,表明河流N2O是大气N2O的源。不同类型的河流,其氮浓度水平、N2O饱和度与释放量均有显著差异,城市纳污型河流——南淝河,其氨氮浓度、N2O饱和度和释放量显著高于其他河流,均值分别达（12.5±6.10）mg N·L-1、1760%±2620%及（363±548）μg N m-2·h-1。研究发现,除南淝河外,所有径流主导型的河流,其N2O饱和度与NO3-含量存在显著线性正相关关系,说明高NO3-含量的河流能增加N2O的表观产量。除南淝河以外的河流N2O释放系数变化范围为0.05%～0.87%,均值为0.20%,较为接近IPCC的参考值0.25%。但我们的研究建议采用修正后的河流N2O释放系数（均值为0.10%）,该系数更能体现河流释放N2O的实际情况。     

土壤磷素吸持饱和度(DPS)评价土壤磷素流失风险研究

随着磷肥施用量增加,土壤磷素累积,由此所引起的土壤磷素流失越来越成为水体磷素的重要来源。本研究采集湖北省主要类型土壤,土壤风干过2 mm筛后,加入不同量的K2HPO4(0,30,40,60,100,160,200,240,300,400 mg P/kg土)进行室内培养,测定土壤M-3P、CaCl2-P和Fe、Al含量,计算土壤磷吸持饱和度(DPS),利用Split-line模型,预测不同土壤类型磷素流失风险。结果表明:土壤M-3P与Fe、Al含量间关系符合y=y0+axb方程(P0.05);土壤DPS与CaCl2-P含量关系,存在一个明显的突变点,即土壤磷素流失环境临界值,超过该值时,CaCl2-P含量急剧增加,但不同土壤类型其临界值差异较大,潮土、红壤和水稻土土壤磷素流失DPS临界值分别为18.8、12.9和13.3%,相对应的CaCl2-P含量分别为2.21、0.92、0.60 mg kg-1,根据以上临界值判断,红壤、水稻土极易发生流失。从区域角度考虑,土壤磷素流失DPS临界值为18.80%,该值能够给当地农业生产过程中的土壤磷素区域环境管理提供指导。     

设施蔬菜栽培对土壤阳离子交换性能的影响

以辽宁省沈阳市于洪地区设施菜地及其相邻旱田土壤为研究对象,测定土壤的有机质、阳离子交换量、交换性盐基离子组成和土壤盐基离子饱和度,分析设施蔬菜栽培对土壤阳离子交换量及交换性盐基离子组成的影响。结果表明:(1)与旱田土壤相比,设施土壤有机质含量明显增加,上下层土壤有机质平均含量分别为35.6 g kg-1和18.0 g kg-1,分别是旱田上下层土壤有机质含量的2.1倍和1.8倍;设施土壤阳离子交换量呈上升的趋势,土壤阳离子交换量与有机质含量呈极显著正相关关系(r=0.603**,n=50,r0.01=0.361)。(2)与旱田土壤相比,不同层次设施土壤交换性盐基总量均有所增加,交换性盐基离子中除交换性Ca2+含量变化不大之外,交换性K+、Mg2+、Na+含量均显著增加;不同层次设施土壤交换性K+、Mg2+、Na+饱和度显著高于旱田土壤,但交换性Ca2+饱和度和盐基饱和度呈下降趋势。     

几种植物色彩采集方法的比较研究

对目前常见的植物色彩采集方法进行了论述,并用NCS比色卡、pantone色彩检测仪和相机3种色彩采集工具对100种植物叶色色彩进行采集,对采集的数据用色彩的亮度和饱和度进行比较,并做了SPSS相关性分析,最后总结了RHS色卡、NCS色卡、pantone色彩检测仪、佳能powershot S5相机4种植物色彩采集方法的优缺点及适用范围。     

可控制土壤水分的新型简易剪切机开发试验

研究坡面崩塌，首先要研究土壤强度，常规采用单面剪切试验，因其不能反映γ－τ关系，而开展此项研究。简易剪切机以常规试验理论为依据，侧重了饱和、不饱和的水分条件、试材的不均一性等方面研究。结果表明，不仅可测土壤强度、土体变形过程，且具有再现性。ε－ｔａｎ，γ－τ相关性强。揭示了吸力Ψ对τ、Ｃ的影响，不仅表现在破坏时，且影响整个变形过程。在剪切变形 ５％内，影响最大。     

山核桃综合管理技术

一、山核桃立地条件选择山核桃较耐寒,怕高温干旱;喜深厚肥沃、微酸至中性、盐基饱和度较高的土壤,怕干燥、瘠薄、强酸、积水的土壤。因此,不可将山核桃栽植在积水的洼地和黄泥土上(黄泥土是酸性较强的土质)。     

不同饱和度脂肪酸日粮对北京鸭生产性能的影响

在0～21日龄和21～42日龄两个阶段日粮中添加牛油、豆油、鱼油等含不同饱和度脂肪酸的油脂，观察对北京鸭生产性能的影响。结果表明，添加油脂主要在北京鸭生长后期表现促生长作用，含n-3系列脂肪酸较高的鱼油组自寺促生长作用最好。     

土壤性质与不同土壤Hg形态的关系

Correlation and path analysis methods were used to study the relationship between soil properties and the distribution of different soil Hg fractions with nine representative soils from Chongqing, China. Results showed that clay (< 2 m) could increase water-soluble Hg (r = 0.700*). Soil organic matter (OM) could enhance the increase of elemental Hg (r = 0.674*). The higher the base saturation percentage (BSP), the more the residual Hg (r = 0.684*). Organic Hg, the sum of acid-soluble organic Hg and alkali-soluble Hg, was positively affected by silt (2～20 μm) but negatively affected by pH, with the direct path coefficients amounting to 1.0487 and 0.5121, respectively. The positive effect of OM and negative effect of BSP on organic Hg were the most significant, with the direct path coefficients being 0.7614 and -0.8527, respectively. The indirect effect of clay (< 2 μm) via BSP (path coefficient = 0.4186) was the highest, showing that the real influencing factor in the effect of clay (< 2 μm) on acid-soluble organic Hg was BSP. Since the available Hg fraction, water-soluble Hg, was positively affected by soil clay content, and the quite immobile and not bioavailable residual Hg by soil BSP, suitable reduction of clay content and increase of BSP would be of much help to reduce the Hg availability and Hg activity in Hg-contaminated soils.     

Alberta油砂地区在两种水文流域森林土壤酸化敏感性研究

Input of large amounts of N and S compounds into forest ecosystems through atmospheric deposition is a significant risk for soil acidification in the oil sands region of Alberta. We evaluated the sensitivity of forest soils to acidification in two watersheds （Lake 287 and Lake 185） with contrasting hydrological regimes as a part of a larger project assessing the role of N and S cycling in soil acidification in forest ecosystems. Fifty six forest soil samples were collected from the two watersheds by horizon from 10 monitoring plots dominated by either jack pine （Pinus banksiana） or aspen （Populus tremuloides）. Soils in the two watersheds were extremely to moderately acidic with pH （CaCl2） ranging from 2.83 to 4.91. Soil acid-base chemistry variables such as pH, base saturation, Al saturation, and acid-buffering capacity measured using the acetic acid equilibrium procedure indicated that soils in Lake 287 were more acidified than those in Lake 185. Acid-buffering capacity decreased in the order of forest floor 〉 subsurface mineral soil 〉 surface mineral soil. The most dramatic differences in percent Ca and Al saturations between the two watersheds were found in the surface mineral soil horizon. Percent Ca and Al saturation in the surface mineral soil in Lake 287 were 15% and 70%, respectively; the percent Ca saturation value fell within a critical range proposed in the literature that indicates soil acidification. Our results suggest that the soils in the two watersheds have low acid buffering capacity and would be sensitive to increased acidic deposition in the region.