Variability Analyses of Alfalfa-Reference to Grass-Reference Evapotranspiration Ratios in Growing and Dormant Seasons

Alfalfa-reference evapotranspiration (ETr) values sometimes need to be converted to grass-reference ET (ETo), or vice versa, to enable crop coefficients developed for one reference surface to be used with the other. However, guidelines to make these conversions are lacking. The objectives of this study were to: (1) develop ETr to ETo ratios (Kr values) for different climatic regions for the growing season and nongrowing (dormant) seasons; and (2) determine the seasonal behavior of Kr values between the locations and in the same location for different seasons. Monthly average Kr values from daily values were developed for Bushland, (Tex.), Clay Center, (Neb.), Davis, (Calif.), Gainesville, (Fla.), Phoenix (Ariz.), and Rockport, (Mo.) for the calendar year and for the growing season (May–September). ETr and ETo values that were used to determine Kr values were calculated by several methods. Methods included the standardized American Society of Civil Engineers Penman–Monteith (ASCE-PM), Food and Agriculture Organization Paper 56 (FAO56) equation (68), 1972 and 1982 Kimberly-Penman, 1963 Jensen-Haise, and the High Plains Regional Climate Center (HPRCC) Penman. The Kr values determined by the same and different methods exhibited substantial variations among locations. For example, the Kr values developed with the ASCE-PM method in July were 1.38, 1.27, 1.32, 1.11, 1.28, and 1.19, for Bushland, Clay Center, Davis, Gainesville, Phoenix, and Rockport, respectively. The variability in the Kr values among locations justifies the need for developing local Kr values because the values did not appear to be transferable among locations. In general, variations in Kr values were less for the growing season than for the calendar year. Average standard deviation between years was maximum 0.13 for the calendar year and maximum 0.10 for the growing season. The ASCE-PM Kr values had less variability among locations than those obtained with other methods. The FAO56 procedure Kr values had higher variability among locations, especially for areas with low relative humidity and high wind speed. The 1972 Kim-Pen method resulted in the closest Kr values compared with the ASCE-PM method at all locations. Some of the methods, including the ASCE-PM, produced potentially unrealistically high Kr values (e.g., 1.78, 1.80) during the nongrowing season, which could be due to instabilities and uncertainties that exist when estimating ETr and ETo in dormant season since the hypothetical reference conditions are usually not met during this period in most locations. Because simultaneous and direct measurements of the ETr and ETo values rarely exist, it appears that the approach of ETr to ETo ratios calculated with the ASCE-PM method is currently the best approach available to derive Kr values for locations where these measurements are not available. The Kr values developed in this study can be useful for making conversions from ETr to ETo, or vice versa, to enable using crop coefficients developed for one reference surface with the other to determine actual crop water use for locations, with similar climatic characteristics of this study, when locally measured Kr values are not available.     

2010年山东聊城市2次大暴雨形成机制的对比分析

从环流形势、物理量场、雷达回波特征方面对比分析了山东省聊城市不同季节2次大暴雨的形成机制.结果表明:夏季大暴雨具有降水量大、短时件强、降水强度较强、危害大等特点.夏季大暴雨能量场强,多伴有强对流天气发生;大暴雨存在中气旋和逆风区,并且对应于暴雨和灾害性天气的发生区域;秋季大暴雨发生时,雷达回波强度不是很强,但持续时间比较长;秋季大暴雨发生时,物理量场上一些暴雨指标比夏季大暴雨稍低;大暴雨难以预报.     

不同季节蚯蚓活动对土壤微生物类群数量的影响

采用人工培养的蚯蚓和野生环毛蚓在试验土壤中进行接种,跟踪测量不同季节中蚯蚓-微生物交互作用下土壤微生物类群数量的变化,探讨了蚯蚓活动对土壤中不同微生物类群数量的影响.结果表明,接种蚯蚓后土壤中微生物类群的数量都有不同程度的增加,细菌数量的增加比放线菌和真菌明显一些.春季接种蚯蚓土壤中的细菌、放线菌和真菌数量的增加程度要比其他季节高.人工培养的蚯蚓和野生环毛蚓对土壤中不同季节微生物类群数量影响的差异程度不显著.     

A Major QTL,Ghd8,Plays Pleiotropic Roles in Regulating Grain Productivity,Plant Height and Heading Date in Rice

Rice yield and heading date are two distinct traits controlled by quantitative trait loci (QTLs). The dissection of molecular mechanisms underlying rice yield traits is important for developing high-yielding rice varieties. Here,we report the cloning and characterization of Ghd8,a major QTL with pleiotropic effects on grain yield,heading date,and plant height. Two sets of near isogenic line populations were developed for the cloning of Ghd8. Ghd8 was narrowed down to a 20-kb region containing two putative genes,of which one encodes the OsHAP3 subunit of a CCAAT-box binding protein (HAP complex);this gene was regarded as the Ghd8 candidate. A complementary test confirmed the identity and pleiotropic effects of the gene;interestingly,the genetic effect of Ghd8 was dependent on its genetic background. By regulating Ehd1,RFT1,and Hd3a,Ghd8 delayed flowering under long-day conditions,but promoted flowering under short-day conditions. Ghd8 up-regulated M0C1,a key gene controlling tillering and branching;this increased the number of tillers,primary and secondary branches,thus producing 50% more grains per plant. The ectopic expression of Ghd8 in Arabidopsis caused early flowering by 10 d-a situation similar to the one observed by its homolog AtHAP3b. When compared to wild-type under long-day conditions;these findings indicate the conserved function of Ghd8 and AtHAP3b in flowering in Arabidopsis. Our results demonstrated the important roles of Ghd8 in rice yield formation and flowering,as well as its opposite functions in flowering between rice and Arabidopsis under long-day conditions.     

HPLC测定不同采收期川楝子中阿魏酸的含量

[目的]测定不同采收期川楝子中阿魏酸的含量,并考察阿魏酸在采收期内的含量变化.[方法]采用高效液相色谱法,色谱柱为UltrasphereTM-ODS柱(4.6 mm ×250 mm,5μm),流动相为乙腈-0.1%磷酸溶液(15:85=V:V),流速为1.0 ml/min,检测波长为322nm,柱温为25℃.[结果]不同采收期川楝子药材中阿魏酸含量无显著变化,以1月份采集的样品中阿魏酸含量最高.[结论]该方法简便、快速,可为川楝子确定最佳采收期提供科学依据.     

浅析GPS 高程测量

通过GPS 高程测量原理的分析,介绍GPS 高程测量的常用方法,根据GPS 控制测量网的网型不同,给出高程模型拟合的2 种主要方法:多项式曲线拟合和多项式曲面拟合,并提出提高GPS 测量高程精度的主要措施及方法。     

不同植物根系对土壤抗冲性的影响

[目的]研究不同植物根系对土壤抗冲性的影响.[方法]采用改进的原状土冲刷水槽法,探讨了不同雨量、不同坡度下,4种植物的土壤抗冲性与根系生物量的关系.[结果]在小雨冲刷下,不同植物上层土壤的抗冲性和根系生物量随着坡度的增大而增强,而下层土壤表现出相反趋势;中雨冲刷下,丁香对上层土壤抗冲性的影响较大,而丁香、红瑞木下层土壤的抗冲性和根系生物量随着坡度的增加而减小;大雨冲刷下,不同植物上层土壤的抗冲性基本上随着坡度的增大逐渐增强,而根系生物量呈相反趋势,在下层土壤中其表现规律不一致.另外,土壤抗冲性与根系生物量密切相关,中雨、大雨冲刷下土壤抗冲指数与根系生物量的相关性明显高于小雨冲刷下.[结论]不同植物根系对土壤抗冲性有明显影响,可为水土流失区的植被修复提供科学依据.     

PEG浸老化种子对茎瘤芥幼苗株高的影响

[目的]分析聚乙二醇(PEG)浸老化种子对茎瘤芥幼苗株高的影响.[方法]使用不同浓度PEG 6000(5%、10%、15%、20%、25%、30%、35%),以不同处理时间(4、8、12、16、20、24 h)浸茎瘤芥老化种子后,测量其幼苗株高.[结果]与对熙相比,5%、10%、15%、20%、25%、30%PEG 6000以不同处理时间,浸茎瘤芥老化种子后,其幼苗株高均显著增加(P<0.05).[结论]25%PEG 6000浸茎瘤芥老化种子12 h.其幼苗株高最高.     

东烧厂提高烧结料层厚度的试验研究

在实验室条件下,以鞍钢集团矿业公司东烧厂赤浮精矿为主要原料进行了600 mm提高到700 mm的厚料层烧结杯试验,获得了生产化学成分稳定、机械强度高、粒度均匀、高温冶金性能良好烧结矿的最佳生产工艺参数,给出了烧结过程中参数变化对烧结矿技术经济指标的影响规律,为鞍钢东烧厂进一步提高料层厚度提供了依据。     

水稻纹枯病在不同栽培方式稻田发生情况调查

2008年和2009年的早稻和晚稻分蘖盛期、孕穗末期-黄熟期对点播、撒播、强化栽培、插植、抛秧5种栽培方式种植水稻的稻田进行纹枯病发生情况调查.结果显示,纹枯病在不同栽培方式的稻田之间是有差异的,强化栽培稻田纹枯病的发病率和病情指数最高,抛秧稻田发病率和病情指数次之,插植稻田发病情况居中,点播和撒播稻田最低.五种栽培方式稻田在孕穗末期-黄熟期的纹枯病发病率和病情指数均高于分蘖盛期.调查研究建议,要做好预防工作,适时用药,合理种植密度,以期达到控制该病害的目的.