Variability and Correlation between Exchangeable Sodium Percentage and Sodium Adsorption Ratio in Vertisols of Sudan

Vertisols in the Sudan occur under different climatic zones, ranging from arid in the north to tropical monsoon in the south, with rainfall varying from 150 mm to 1000 mm per annum. In this study, the exchangeable sodium percentage (ESP) was estimated from the sodium adsorption ratio (SAR); values of SAR and ESP for all identified soil series of Vertisols in the Sudan were extracted from the available data. These data were used to examine the variability in SAR and ESP in these soils using coefficient of variation (CV) as an index and then to regress ESP on SAR for the three master horizons (A, AC, C) and pooled data for all horizon. Curvilinear, linear, quadratic, and cubic equations were used to examine the relation between ESP and SAR. The significance of the F ratio and correlation coefficient was tested for individual equation. The soil series were then sorted out into saline and nonsaline, sodic and nonsodic, and the ESP was regressed on SAR once again. The equations used for the regression were curvilinear and first‐, second‐, and third‐degree polynomial equations. Then analysis of variance (ANOVA) was used to screen any significant difference between the estimated values of ESP (using these equations and USDA salinity laboratory equation) on one hand and the actual (measured) values of ESP. The results revealed that ESP and SAR are highly variable irrespective of depth despite slight decrease with depth. Furthermore, ESP is more variable than SAR in horizons A and AC but less variable in horizon C. The regression equations indicated that ESP might be reasonably estimated from SAR. However, different equations were appropriate for different horizons. Moreover, the result indicated that in most of the cases the relation between ESP and SAR better fits quadratic equations. But for simplicity, linear equations for all horizons could be used to estimate ESP from SAR.     

Selective Absorption of K over Na in Sugar Beet Cultivars and its Relationship with Yield and Quality in Two Contrasting Environments of Central Greece

Selective absorption (SA) of K over Na (i.e. the preferential absorption of K over Na) has been proposed as a Na tolerance mechanism but genotypic variation for this trait has not been assessed with sugar beet in the field. Thus, the aim of this study was to explore the variation of SA in 14 sugar beet cultivars and to relate SA with yield and root quality in two sites of central Greece (Amfithea and Pyrgetos). Genotypic variation for SA was significant and the SA values were higher in Pyrgetos, the site with the lower soil K and Na concentrations. In Pyrgetos, a favourable environment for sugar beet growth, cultivars yielded more and root quality was better. In that site, a negative relationship between SA and yield (fresh root weight, sugar yield) was found indicating that strong Na exclusion from root is a disadvantage for high yielding. Negative SA–yield relationships were evident in Amfithea when five cultivars with very low SA values (<1.00) were excluded from the analysis. Combined all the cultivars, curvilinear functions were the best-fitted curves for the SA–yield relationships. In Amfithea, where sugar beets had lower water content in root (WCR), a significant, positive correlation between SA and % sucrose content in fresh root weight was found. This finding was ascribed to the dilution of sucrose in roots due to the increased WCR as a result of the increased root Na concentration. In both sites, SA was positively related with root K concentration and negatively with Na concentration. The positive correlations between SA and root α-amino N concentration indicated that sugar beet N nutrition could be affected by the genotypic ability to exclude Na from the root.     

十二烷基硫酸钠对大豆基木材胶黏剂的改性作用

采用10.0g·kg^-1的十二烷基硫酸钠（SDS）改性质量分数为250.0g·kg^-1的大豆粉浆液,制成SDS改性大豆基木材胶黏剂（SF）,运用单因素和正交试验法考察了pH值、反应温度和反应时间对改性SF胶耐水胶合强度的影响。试验结果表明,SDS改性大豆基木材胶黏剂的最佳工艺：pH8,反应温度35℃,反应时间4h。改性后的SF胶Ⅱ类耐水胶合强度为0.70MPa。由红外光谱分析可知,SDS改性使大豆蛋白质分子大量的非极性基团外露,增加了蛋白质分子的疏水性,提高了改性SF胶的耐水胶合强度。图4表3参10     

The effects of age on the erythrocyte sodium and potassium concentrations of dairy cows during late pregnancy and early lactation

Blood samples were taken at weekly intervals from 54 dairy cows (mainly Friesians and Jerseys) during the periods 8 weeks before and 8 weeks after calving. The cows were divided into two age groups; group 1 consisting of 26 cows aged 2 1/2 years and group 2 consisting of 28 cows aged 5–9 years. The changes in the erythrocyte sodium (ENa) and the erythrocyte potassium (EK) concentrations before and after calving were expressed as the slopes for each component regressed on weeks. In the older cows the concentration of ENa decreased (p<0.05) while that of EK increased (p<0.05) after calving. Both the ENa and EK concentrations varied significantly (p<0.01) between cows in the two age groups. The prepartum and postpartum ENa and the postpartum EK concentrations varied significantly (p<0.05) between weeks. EK type did not influence the changes in ENa or EK concentrations before or after calving.     

饮水高钠诱发的肉鸡腹水综合征的血液流变学特征

为查明高钠饮水与肉鸡腹水综合征的病因学关系，将２４０只健康ＡＡ肉鸡随机均分为试验Ⅰ、Ⅱ和对照３个组，从８日龄起分别饮用含Ｎａ＋为０．０６％、０．１２％和０．００％的饮水，动态对比观察各组肉鸡临床表现、血液红细胞压积（ＰＣＶ）、红细胞变形性（ＥＤ）、右心室（ＲＶ）和全心室（ＴＶ）的重量比（ＲＶ／ＴＶ）。结果表明，高钠饮水可以诱发腹水综合征；肉鸡在摄入过量Ｎａ＋时，出现肺动脉高压（ＰＨ）、ＰＣＶ增加和ＥＤ下降等血液流变学特性的改变，促进了腹水综合征的形成。     

氯化钠对饲喂棉饼诱发山羊泌尿系结石的预防试验

16只3~5月龄阉割波尔公山羊随机分为4组,即对照Ⅰ组(n=3)、对照Ⅱ组(限水对照组n=3)、试验Ⅰ组(n=5)、试验Ⅱ组(限水试验组,n=5)。对照组饲喂羊精料和花生秧,试验组饲喂棉饼和稻草,同时在试验组棉饼中加入4%棉饼量的氯化钠,对照Ⅰ组和试验Ⅰ组在试验期间不限制饮水,而对照Ⅱ组和试验Ⅱ组每天限制饮水,经预试期后试验期为4个月。结果表明:(1)添加氯化钠各试验组均未发现临床型尿石症,未添加氯化钠对照Ⅰ组有1头发病,未添加氯化钠限水对照Ⅱ组有3头发病。(2)添加氯化钠不限制水组,山羊的饮水量、排尿量较未添加氯化钠组(对照组)明显增加,尿液pH值明显降低,且差异显著;而添加氯化钠限水组,山羊的排尿量、尿液pH值与限水对照组差异不显著。(3)两个试验组血清醛固酮含量较对照组明显降低,并且尿沉渣生成量明显减少。由此推测氯化钠预防棉饼诱发山羊泌尿系结石的机理是通过降低血清中的醛固酮含量,减轻醛固酮对肾脏的损害,减少了结石核心的形成和尿液中盐类结晶沉着点,在非限饮水的情况下羊还可通过增加饮水量和排尿量,使沉渣生成量减少,从而有效地防止尿石症的发生。     

NaOH溶液脱绒对白羊草种子活力的影响

[目的] 探究NaOH溶液脱绒处理对白羊草（Bothriochloa ischaemum）种子活力的影响,为机械化播种提供便利条件。[方法] 分别利用浓度为10%、20%、30%、40%、50%（W/V）的NaOH溶液对白羊草种子进行脱绒处理0（CK）、1、5、10、15 min,分析其对发芽率（Gp）、发芽指数（Gi）、平均发芽时间（MGT）、幼苗活力指数（SVI）的影响,筛选白羊草种子NaOH溶液脱绒的最佳条件。[结果] NaOH溶液浓度及处理时间均对白羊草种子活力具有极显著（P<0.01）影响。相同处理时间下,白羊草种子脱绒1~10 min后Gp、Gi随NaOH溶液浓度的增加而增加,脱绒1 min和10 min后SVI随着NaOH溶液浓度的增加而增加,脱绒5 min后SVI随NaOH溶液浓度的增加呈先降低后升高的趋势,脱绒15 min时Gp、Gi和SVI随NaOH溶液浓度的增加呈先升后降的趋势;在20%~50%的NaOH溶液浓度下,脱绒后白羊草种子Gp、Gi和SVI随处理时间的增加呈先升后降的趋势。经NaOH溶液脱绒处理后白羊草种子的MGT均高于CK。[结论] 适宜浓度的NaOH溶液浸种能有效脱去白羊草种子表面的绒毛,提高白羊草种子的活力。浓度为50%的NaOH溶液浸种5 min对白羊草种子活力的促进效果最好。     

硫代硫酸钠标准溶液浓度不稳定现象初探

溶液的酸度、二氧化碳、空气、微生物、光照及人为和环境等因素对硫代硫酸钠标准溶液浓度的稳定性有很大的影响,继而造成氮肥生产中有关碘量分析法的误差,通过控制溶液的pH值,防止二氧化碳气体的渗入,加强对分析人员的管理,可从根本上解决生产实际中硫代硫酸钠标准溶液出现的析硫现象,保持其浓度的稳定性.