不同生长年限王草的营养价值研究   总被引：2，自引：0，他引：2  

陈勇  甄莉  罗富成  毛华明  赵雪妮  左应梅 《中国饲料》2005,(16):30-31

本文对生长第1、2、3年的王草在100cm高度时刈割的营养成分及其体外干物质、有机物降解率进行分析研究。结果表明:不同生长年限王草第1年的粗蛋白质显著高于第2、3年(P<0.05),而中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)显著低于第3年(P<0.05)。干物质、有机物的降解率第1年最高,第3年的最低,但差异不大。  相似文献   

稻瘿蚊间歇性暴发原因和治理对策探讨   总被引：3，自引：0，他引：3  

王隆都 《中国植保导刊》2003,23(1):8-11

通过多年的系统调查和观察,明确了稻瘿蚊发生具有间歇性、隐蔽性、暴发性、毁灭性和专一性等5个特点,分析了其在大田县间歇大发生有5个方面的因素。防治上提出农业防治可采取“铲”、“避”、“改”等方法,化学防治应选用具有强触杀、强渗透力药剂,采用毒土法施药技术。  相似文献   

丘陵红黄壤区施用399对“一种两收”再生稻根系和产量的影响     

蔡克桐  沈其文  黄志谋  施仕胜  耿协议 《安徽农业科学》2015,(26):51-52

[目的]研究399对"一种两收"再生稻的影响。[方法]以适宜丘陵红黄壤种植的丰两优香1号、准两优527、宜优673再生稻品种为材料,分别设置喷施399和不喷施399(CK)2种处理,研究各处理对再生稻根系和产量的影响。[结果]结果表明:施用399使水稻在生育期上延缓成熟,且施后再生稻的总根系数量、白根数量、根鲜重、根干重、根体积大幅度增加,同时在两季总产量上准两优527、丰两优香1号和宜优673品种分别比对照增产6.39%、4.86%、5.94%。[结论]施用399有利于准两优527、丰两优香1号和宜优673再生稻品种再生根的发生。  相似文献   

Equine influenza vaccination in the UK: Current practices may leave horses with suboptimal immunity     

Amie Wilson  Gina Pinchbeck  Rachel Dean  Catherine McGowan 《Equine veterinary journal》2021,53(5):1004-1014

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新冠肺炎疫情与猪肉价格波动初探     

马琳 《猪业科学》2021,38(2):46-49

基于2020年3月-2020年10月猪肉价格及新冠肺炎疫情指数,借助VAR模型,定量研究新冠肺炎疫情对于猪肉价格的影响。研究结果表明:新冠肺炎疫情对猪肉价格存在影响,促使猪肉价格上涨,在此基础上文章提出相应措施。  相似文献   

The post-ovulatory rise in progesterone is lower and the persistence of oestrous behaviour longer during the first compared with the second cycle of the breeding season in mares     

John R. Newcombe  Sandra Wilsher  Juan Cuervo-Arango 《Reproduction in domestic animals》2023,58(1):141-145

Mares are seasonally polyoestrous breeders. Therefore, the first ovulation of the season, following winter anoestrus, is the only cycle in which mares ovulate without the presence of an old CL from the previous cycle. The objective of this study was to compare the length of oestrous behaviour, and plasma progesterone concentrations during the early post-ovulatory period between mares after the first and second ovulation of the breeding season. Overall, 38 mares and 167 oestrous periods were used in the study. From those, 11 mares were used during the first and subsequent oestrous period to measure and compare the post-ovulatory rise in progesterone concentration, whereas all the mares were used to compare the length of the post-ovulatory oestrous behaviour between the first and subsequent cycles of the breeding season. The persistence of the post-ovulatory oestrus was longer (p < .001) following the first ovulation of the year (median of 52 h) compared with the subsequent ovulations (median of 36 h for second and later ovulations groups; n = 38 mares). The progesterone concentration at any of the four 8 h-intervals analysed (28, 36, 76 and 84 h post-ovulation) was lower (p < .01) following the first versus the second ovulation of the year. By 36 h post-ovulation the progesterone concentration of mares at the second ovulation of the year had passed the threshold of 2 ng/ml (2.1 ± 0.33 ng/ml), whereas in the first cycle it was 1.2 ± 0.13 ng/ml. In conclusion, mares had lower progesterone concentrations in their peripheral circulation and longer persistence of oestrous behaviour following the first ovulation of the year compared with the second and subsequent ovulatory periods of the breeding season.  相似文献   

水稻灌溉效益分摊系数试验研究   总被引：1，自引：1，他引：1  

时光宇  沈佩君 《中国农村水利水电》1997,(5):19-21

通过试验方法，选择不同的降雨年型，系统地分析了淠史杭灌区不同降雨年型的灌溉增产率，灌溉效益扮摊系数；找出了水稻灌溉效益分摊系数与水稻生育期降雨量，灌水量之间的经验公式，对本地区及气候条件相似地区具有一定的参考价值。  相似文献   

短学期制下植物学实验课程开设探索   总被引：2，自引：0，他引：2  

刘振国 《安徽农业科学》2010,38(22):12259-12260

介绍了短学期制下植物学实验课程概况,指出了课程开设面临的问题,提出了相应的解决对策与建议。  相似文献   

蓖麻枯萎病主要发生规律的研究   总被引：2，自引：0，他引：2  

沙洪林  晋齐鸣  李红  李大敬 《吉林农业科学》2003,28(5):26-29

主要对蓖麻枯萎病的初侵染源和影响蓖麻枯萎病的主要因子进行了研究,初步明确了土壤、病残体、种子和有机肥是蓖麻枯萎病的主要初侵染源,轮作、不同生育期、湿度、品种和前茬作物等是影响蓖麻枯萎病发生的主要因子。  相似文献   

Population dynamics of tree species in southern Quebec,Canada: 1970–2005     

Louis Duchesne  Rock Ouimet 《Forest Ecology and Management》2008

Over the last few decades, several phenomena contributed to modify the structure and composition of the eastern North American forests. Along with forest management, disturbances such as insect defoliation, global environmental changes, acid deposition, and rising atmospheric CO₂ concentrations, have been identified as phenomena that could affect forest structure and composition. Currently, there is very little quantitative information on the resulting effect of multiple disturbances on the main parameters of forest dynamics (growth, mortality, and recruitment). Using available data from the Quebec permanent sample plots network, we analyzed the ecological response of tree species populations to the combined effect of contemporary global environmental changes, disturbance regimes, and forest management practices over the last 30 years in southern Quebec. The results indicate that the main parameters of forest dynamics changed considerably over the last three decades. The last spruce budworm outbreak initiated a successional change in coniferous stands. The basal area of Abies balsamea and Picea glauca, the most abundant coniferous species, decreased by 29.7%, while pioneer species abundance increased. For late successional deciduous species, observed changes in forest dynamics appear to be mainly associated with global environmental changes rather than with natural disturbances or forest harvesting. The results indicate that inferring responses of tree population dynamics to global environmental changes can be very complex or even misleading considering the confounding effects of other disturbance agents. The results also suggest that the ecosystem-based management approach promoted by forest ecologists, aimed at maintaining landscape stand composition and structures similar to those characterizing natural environments, will not be easily achieved. Forest ecosystems are highly dynamic and disturbances other than tree harvesting appear to have been the major factors affecting their pattern of change over the last three decades. Forest managers should consider adaptive management approaches that will consider the contemporary evolution of forest ecosystems in a changing environment.  相似文献