滇中冷凉山区不同播期反季花椰菜产量效益分析     

李艳兰  张云明  李祥  胡新洲  段永华  刘坚坚  安正云  易丽华  蔡述江  王爱明  陶春红  史兰芬  李文静  杨进成 《农学学报》2021,11(9):58-63

为摸索滇中高海拔冷凉山区反季节栽培花椰菜的最佳播期以集成高效栽培技术推广应用,于2017—2018年选择海拔2250 m的云南省峨山县塔甸镇大西村地块进行9个播期的2年随机区组试验。结果表明,花椰菜生育期随播期推迟而延长,而花球采收期除播期7月10日外随播期推迟而逐渐增长;花椰菜株高、外叶数、开展度、球高、球径和单球重等农艺性状有随播期延迟呈现先逐渐减小而后又逐渐增大的趋势;莲座期黑腐病和霜霉病的病情指数随着播期的延迟呈现先逐渐升高而后又逐渐下降的趋势;花椰菜小区产量随着播期的延迟呈现先逐渐下降而后又逐渐提高的趋势,播期4月20日和4月30日与其余7个播期产量之间的差异达极显著水平。综合花椰菜在冷凉山区反季节栽培的生产实际和各播期产量产值及商品性表现,推荐滇中高海拔冷凉山区反季节栽培花椰菜的最佳播期为4月20—30日。  相似文献   

武汉市桔梗科一物种新记录——卵叶异檐花     

安玫  李雅绚 《湖北林业科技》2020,49(2):28-30

报道了武汉市外来入侵植物新记录一种,为桔梗科Campanulaceae异檐花属Triodanis卵叶异檐花Triodanis perfoliata subsp.biflora(Ruiz et Pavon)Lammers。卵叶异檐花原产于美洲,在武汉地区是首次发现,凭证标本保存于长江文明馆(武汉自然博物馆)。  相似文献   

Impact of grassland contract policy on soil organic carbon losses from alpine grassland on the Qinghai–Tibetan Plateau          下载免费PDF全文

J. Cao  Y. Gong  E. T. Yeh  N. M. Holden  J. F. Adamowski  R. C. Deo  M. Liu  J. Zhou  J. Zhang  W. Zhang  S. Zhang  D. Sheng  S. Yang  X. Xu  M. Li  Q. Feng 《Soil Use and Management》2017,33(4):663-671

Carbon storage in the soils on the Qinghai–Tibetan Plateau plays a very important role in the global carbon budget. In the 1990s, a policy of contracting collective grasslands to smaller units was implemented, resulting in a change from the traditional collective grassland management to two new management patterns: a multi‐household management pattern (MMP: grassland shared by several households without enclosures) and a single‐household management pattern (SMP: grassland enclosed and used by only one household). In 2016, 50 MMP and 54 SMP winter pastures on the Qinghai–Tibetan Plateau were sampled to assess the differences in soil organic carbon (SOC) between the two management patterns. Results showed that average SOC was significantly greater under MMP than under SMP, with an estimated 0.41 Mg C/ha/yr lost due to SMP following the new grassland contract. Based on the government's grassland policy, four grassland utilization scenarios were developed for both summer and winter pastures. We found that if the grassland were managed under SMP, likely C losses ranged between 0.31 × 10⁷ and 6.15 × 10⁷ Mg C/yr across the Qinghai–Tibetan Plateau relative to MMP, which more closely resembles pre‐1990s grassland management. Previous estimates of C losses have only considered land use change (with cover change) and ignored the impacts driven by land management pattern changes (without cover change). The new data suggest that C losses from the Qinghai–Tibetan Plateau are greater than previously estimated, and therefore that the grassland contract policy should be reviewed and SMP households should be encouraged to reunite into the MMP. These findings have potential implications for land management strategies not only on the Qinghai–Tibetan Plateau but also other grazing regions globally where such practices may exist.  相似文献   

基于科技文献社会网络分析的"一带一路"科技情报安全研究     

牟笛  陈安 《农业图书情报学刊》2018,30(12):24-28

为明确中国在"一带一路"沿线国家所形成的科技网络中处于怎样的位置,面临怎样的科技情报风险,需要采取哪些措施维护中国科技情报安全,应用智库DIIS理论方法,对科学引文索引中2013年-2017年"一带一路"沿线国家论文合作数据进行社会网络分析,应用管理机制设计"七元组"理论开展科技情报安全机制设计。研究结果显示,中国科技情报的暴露程度较高,科技应用的不可控因素、知识产权保护的挑战、科技情报资源流失的风险同时存在,并与各种非传统安全问题相叠加。切实掌握核心技术,维护知识产权,加强政府、社会对科技交流的监管,防止科技情报被非法利用,是保障科技情报安全的主要途径。  相似文献   

Compatibility of root growth and tuber production of potato cultivars with dynamic and static water‐saving irrigation managements          下载免费PDF全文

S. H. Ahmadi  M. Agharezaee  A. A. Kamgar‐Haghighi  A. R. Sepaskhah 《Soil Use and Management》2017,33(1):106-119

The important root characteristics of root length density (RLD) and root mass density (RMD) generally differ among irrigation managements and potato cultivars. The objective of this study was to investigate the RLD and RMD variations and their functional relationships with gross potato tuber yield for two commercial potato cultivars, Agria and Sante, under different irrigation strategies. Full irrigation and water‐saving irrigation strategies, deficit and partial root drying irrigations, were applied statically (S) and dynamically (D) based on daily crop evapotranspiration. Results showed that SPRD had significantly greater RLD (3.64 cm/cm³) and RMD (132.7 μg/cm³) than other irrigation treatments. Between the potato cultivars, Agria had significantly larger values of RLD (3.50 cm/cm³) and RMD (138.7 μg/cm³) than Sante. The functional relationship between the root growth characteristics and tuber yield showed that under water‐saving irrigations, Agria increased root mass at the expense of gross tuber yield but Sante increased root mass to maintain larger gross tuber yields. However, Agria produced more roots and gross tuber yield than Sante, and it is concluded that Agria is a more drought‐tolerant potato cultivar, which is recommended for tuber production in regions where water might be scarce. It was shown that larger root production in potatoes was associated with improved tolerance to water stress.  相似文献   

Getting cosy in freshwater: Assumed to be brackish pike are not so brackish after all     

Kim Birnie‐Gauvin  Lasse Birch Hjrup  Theis Kragh  Lene Jacobsen  Kim Aarestrup 《Ecology of Freshwater Fish》2019,28(3):376-384

Pike (Esox lucius) occupy coastal streams and rivers of the Baltic Sea, where they attain large sizes (>5 kg). These large sizes are perhaps due to the fact that they can tolerate relatively high salinities and can thus forage in the nearby more productive brackish environments. In an attempt to quantify the extent to which pike utilise brackish environments, and to provide some insight into the underlying causes for brackish water migrations, we tagged 30 pike from a western Baltic river with acoustic transmitters and were able to track 21 individuals for 1 year. Based on experienced from local anglers, this population was assumed to be brackish in nature, where individuals underwent freshwater migrations to spawn. Our findings however suggest that the smallest and most active individuals make short exits into brackish waters and do so on rare occasions. Our results further indicate that neither sex nor size is related to activity level. We suggest that these patterns reflect two distinct behaviours—active and passive—and that large pike can be supported by the food availability in the river, without the need to venture into coastal zones, thus defying the conventional view that Baltic pike are all brackish in nature.  相似文献   

Paternal genomotype affects female growth in a hybrid fish complex          下载免费PDF全文

Sara Carona  Maria J. Collares‐Pereira  M. Filomena Magalhães 《Ecology of Freshwater Fish》2017,26(4):719-721

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呼和浩特市大气污染状况的研究及遥感信息的利用   总被引：1，自引：0，他引：1  

张韬  常同元 《内蒙古林学院学报》1996,18(2):61-69

利用遥感技术结合地物波谱测定和叶表面内大气污染元素的含量测定分析研究大气污染是一种有效可靠的方法。克服了常规大气监测的弊病。充分显示了快速、准确的优越性。为城市规划和环境的综合治理提供了可靠的科学依据。  相似文献   

Studies on the Safety and Immunogenicity of the South African Bluetongue Virus Serotype 2 Monovalent Vaccine: Specific Detection of the Vaccine Strain Genome by RT‐PCR     

S. Hammoumi  E. Breard  C. Sailleau  P. Russo  C. Grillet  C. Cetre‐Sossah  E. Albina  R. Sanchis  M. Pepin  J.‐M. Guibert  And S. Zientara 《Zoonoses and public health》2003,50(7):316-321

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Versuche zur Zyklussynchronisation bei Kühen aus Beständen rnit Fertilitätsproblemen und bei Hybriden zwischen Wisent und Rind mit der PRID-Spirale*     

S. Zdu&#x;czyk  A. Domaszewski  Z. Giiejewski  T. Janowski  A. Zebracki 《Reproduction in domestic animals》1989,24(1):1-7

Inhalt: An 81 Versuchs- und 92 Kontrolltieren der Rasse “Potnische Schwarzbunte” aus 3 Problembetrieben wurde ein Versuch zur Sterilitätsprophylaxe rnit der PRID-Spirale durchgeführt. Anhand klinischer Befunde und Milchprogesteronwerten wurde die Untergruppe aus Kühen mit Ovardystrophie (18 Versuchs- und 22 Kontrolltiere) gebildet und extra ausgewertet. Der Behandlungsbeginn lag zwischen 60 und 80 Tage post partum. Die Versuchstiere wurden mit der PRID-Spirale 12 Tage lang behandelt, die Kontrolltiere erhielten Injcktionen rnit Kochsalzlösung und solche rnit Ovardystrophie wurden zusätzlich mit einer Eierstocksmassage behandelt. Die Versuchstiere wurden 56 und 72 Stunden nach Entfernung der Spirale blind besamt. Die Brunstin-duktionsrate betrug insgesamt 90,1%, bei denen rnit Ovardystrophie 77,7%. Die An-wendung der PRID-Spirale führte zur Verbesserung der Fertilitätslage. Die Gesamt-trächtigkeitsrate lag mit 87,6% bei den Versuchskühenüber derjenigen der Kontrollkü-he mit 79,3%. Die Behandlung der Tiere rnit Ovardystrophie erbrachte eine Gesamt-trächtigkeitsrate von 88,8% bei den Versuchs- und 72,7% bei den Kontrolltieren. Die Zwischentragezeit betrug bei den Versuchstieren 101,2 Tage und bei den Kontrolltieren 113,3 Tage (p ≤ 0,05). Bei den azyklischen Tieren lag die Zwischentragezeit bei 104,6 Tage bzw. 134,7 Tage (p ≤ 0,05). In einem anderen Versuch wurde 20 Hybriden zwischen Wisent und Hausrind rwecks Zyklussynchronisation die PRID-Spirale verabreicht. Die Brunstinduktionsrate betrug 66,6%, das Erstbesamungsergebnis nach Doppelbesamung 30%, die Gesamtträchtig-keitsrate nach dem Decken der umrindernden Kreuzungstiere rnit einem Bullen 90%. Die Deckperiode konnte verkürzt werden. Contents: Investigations on the synchronization of estrus cycle in cattle from farms with fertility problems and in cross-breeds between bison and cattle with a PRID-de-vice In 81 experimental and 92 control animals of the “Polish Black and White” breed derived from 3 farms with fertility problems an investigation was carried out for sterility prophylaxis using the PRID-device. Based on clinical findings and milk progesterone values cattle with ovarian dystrophy (18 experimental and 22 control animals) from a special group were used. The begin of treatment was between 60 and 80 days post partum. All experimental animals had received a PRID-device for a duration of 12 days. Control animals were injected with physiological saline solution and animals with ovarian dystrophy were treated additionally with ovarian massage. Experimental animals were inseminated 56 and 72 hrs after removal of the device. All animals taken, estrus was induced in 90.1% of the animals, while only 77.7% of animals with ovarian dystrophy came to estrus. Application of the PRID-device led to an improvement of fertility. Pregnancy rates in experimental animals were 87.6%, while only 79.3% of the control animals were pregnant. Treatment of animals with ovarian dystrophy resulted in 88.8% pregnancies for treated and 72.7% for control animals. Experimental animals were non-pregnant for a duration of 101.2 days, while control animals remained non-pregnant for 113.3 days (p < 0.05). Acyclic cattle had a non-pregnant period of 104.6 days and 134.7 days (p < 0.05) respectively. In a second experiment 20 cross-breeds between bison and domestic cattle were treated with a PRID-device for synchronization of the estrus cycle. The rate of estrus induction was 66.6%, the fertility after double insemination 30%, the total pregnancy rate improved after mating with a bull of animals that had not conceived to 90%.  相似文献