不同外源激素浸种对甜椒苗期生长发育的影响

分别用5 mg/L S3307和10 mg/L IBA 10 mg/L NAA对甜椒种子进行浸种试验的结果表明:无论从形态指标还是生理指标来看,均以5 mg/L S3307溶液浸种效果优于10 mg/L IBA 10 mg/L NAA,以5 mg/LS3307溶液浸种可明显降低甜椒幼苗株高,增加茎粗和植株干重、增大根冠比,提高叶片叶绿素含量和根系活力,增强幼苗根系吸收能力,但对叶面积和类胡萝卜素含量影响不明显.     

不同因素对荷斯坦牛体细胞评分的影响

利用陕西西安现代农业综合开发区4个奶牛场253头荷斯坦牛2000～2005年的7 082份DHI记录中的体细胞计数(SCC),分析了胎次、产犊季节和泌乳阶段对荷斯坦牛体细胞评分(SCS)的影响,并分析了不同牛场问SCS的差异。结果表明,SCS在不同牛场、不同胎次、不同产犊季节和不同泌乳阶段均存在显著差异,且这些因素相互作用对SCS有极显著影响,3场的SCS显著低于其他牛场;6～9月份平均SCS最高,5月份和10月份次之,其他月份较低;随胎次及泌乳月份的增加,SCS呈增加趋势。     

黄土丘陵区雨季栽植油松试验

在陕北黄土丘陵沟壑区以春季栽植的2年生油松为对照,开展了雨季栽植2年生和1年生油松试验. 通过测定春季、雨季栽植油松后45 d的气候、土壤水分,调查栽后4年内啮齿类动物的危害状况和油松的存活率、生长状况后得知:雨季的降水量比春季大,空气相对湿度高,风速低,气温与地温高,土壤含水量高,蒸发量在栽植后26 d内较低,利于油松缓苗和生长;雨季栽植躲过了栽植当年啮齿类动物的春季危害高峰,苗木存活率高. 从栽植当年到栽植后第4年,雨季栽植的油松存活率一直比春季栽植的高,雨季栽植的2年生苗木树体生长量比春季栽植的2年生苗木生长量大,雨季栽植的1年生苗木树体生长量与春季栽植的2年生苗木基本相同. 雨季栽植油松能够显著提高苗木的存活率,促进苗木生长.      

2004年广西桂南稻作区早季迟熟组区域试验报告

以特优63为对照,将21个水稻品种分为A、B两组参加2004年广西桂南稻作区早季迟熟组区试试验。试验结果表明,A组Ⅱ优416、D优202、F 3001、冈香优527、贺两优86和天优1025以及B组T优855、华优122、培杂279、汕优416和特优986 11个水稻品种的产量、米质、抗性等优于对照特优63,一般平均产量为8668.5~9264.0kg/hm2;推荐省级评审,于2005年3月通过广西农作物品种审定委员会审定。     

苏南两熟茭白生态学分类与栽培

根据苏南十多个两熟茭白品种的分蘖习性和孕茭对外界温度的要求,分成苏州型茭白(温度敏感型)和无锡型茭白(温度不敏感型)两类。苏州型茭白植株高大,长势旺盛,分株性强,孕茭适温为20℃左右。无锡型茭白植株较矮小,长势中等,母墩分蘖性较强,孕茭适温为15—30℃,以25℃为最适。两类茭白的选种方法、肥水管理均存在较大差异,本文提出了不同类型茭白的栽培管理措施。     

不同海拔岷江冷杉林凋落物量及其季节动态变化研究

本文对四川王朗国家自然保护区不同海拔岷江冷杉森林群落内的凋落物总量、各凋落物组分随海拔的变化及其季节动态进行了研究,结果显示,各凋落物组分和总凋落物的年产量在不同海拔间均无显著性差异,年总凋落物量在3 537.18~4 761.84 kg.hm-2.a-1,高于同一地区的相似群落,表明在该区域岷江冷杉林具有相对较高的生...     

低山区飞播造林最佳季节选择的调查研究

通过对洛南县春、秋两季不同自然条件的调查分析及在不同生态环境条件下,油松、侧柏飞播造林成苗数量。调查研究结果表明：秋季飞播造林出苗率和幼苗保存率明显高于春季飞播造林,因此,秋季是低山区飞播造林的最佳季节。     

Using digital repeat photography and eddy covariance data to model grassland phenology and photosynthetic CO2 uptake

The continuous and automated monitoring of canopy phenology is of increasing scientific interest for the multiple implications of vegetation dynamics on ecosystem carbon and energy fluxes. For this purpose we evaluated the applicability of digital camera imagery for monitoring and modeling phenology and physiology of a subalpine grassland over the 2009 and 2010 growing seasons.We tested the relationships between color indices (i.e. the algebraic combinations of RGB brightness levels) tracking canopy greenness extracted from repeated digital images against field measurements of green and total biomass, leaf area index (LAI), greenness visual estimation, vegetation indices computed from continuous spectroradiometric measurements and CO₂ fluxes observed with the eddy covariance technique. A strong relationship was found between canopy greenness and (i) structural parameters (i.e., LAI) and (ii) canopy photosynthesis (i.e. Gross Primary Production; GPP). Color indices were also well correlated with vegetation indices typically used for monitoring landscape phenology from satellite, suggesting that digital repeat photography provides high-quality ground data for evaluation of satellite phenology products.We demonstrate that by using canopy greenness we can refine phenological models (Growing Season Index, GSI) by describing canopy development and considering the role of ecological factors (e.g., snow, temperature and photoperiod) controlling grassland phenology. Moreover, we show that canopy greenness combined with radiation use efficiency (RUE) obtained from spectral indices related to photochemistry (i.e., scaled Photochemical Reflectance Index) or meteorology (i.e., MOD17 RUE) can be used to predict daily GPP.Building on previous work that has demonstrated that seasonal variation in the structure and function of plant canopies can be quantified using digital camera imagery, we have highlighted the potential use of these data for the development and parameterization of phenological and RUE models, and thus point toward an extension of the proposed methodologies to the dataset collected within PhenoCam Network.     

Assessing drought risk and irrigation need in northern Ethiopia

Long-term climate data of four stations in the northern Ethiopia were analyzed in combination with information from local farmers and documented materials. From this analysis, a suitable drought-assessing technique was developed and site-specific needs for supplementary irrigation were explored. Results showed that our technique for assessing drought and crop failure corresponded well with farmer observations. The three major causes of crop failure (dry spells, short growing period and “total lack of rain”) which were explicitly listed and ranked by the local farmers were found to match the analyzed data well. The agro-meteorological variables with the most severe consequences were “short growing period” and “total lack of rain”. To prolong the growing period, supplementary irrigation is recommended in the month of September for three of the stations (Maychew, Mekelle and Adigudom) because: (1) rain frequently stops in early September or late August and crops have no other source of water for the rest of the growing period; (2) sufficient surface runoff can be harvested in July and August to be stored in farm ponds and used in September; (3) more cultivable land can be irrigated if supplementary irrigation is scheduled only for the month of September; and (4) giving supplementary irrigation in September can cut yield reduction by over 80% and crop failure by over 50%, except at Alamata. At Alamata, supplementary irrigation must be scheduled for July. The conditions experienced during the famine years of the early 1980s were primarily caused by the continued total rain failure over multiple years. Giving supplementary irrigation in July or September would probably not have mitigated the effects of these droughts, especially at Alamata and Maychew stations.     

四川中籼中熟杂交水稻产量与主要经济性状的分析

通过对1996—2005年四川省中籼中熟杂交水稻区试试验86个组合的116组数据进行相关和通径分析,结果表明,每穗总粒数与每穗实粒数,结实率与产量均成极显著正相关,有效穗对产量的贡献最大,但由于有效穗数通过穗粒数的间接副作用较大,所以有效穗数太大对提高产量反而不利。笔者认为,四川中籼中熟杂交水稻高产应在保证一定穗数的基础上,主攻每穗实粒数,同时兼顾提高千粒重,协调好性状之间的关系。其单产9.0t/hm2的产量构成因素是:有效穗数265～270万/hm2,每穗总粒数180～200粒,结实率大于84%,千粒重27～29g。