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991.
用浓硫酸处理皂荚种子,分析其对种子膨胀率和发芽率的影响。以同种源、长势一致的2年生皂荚实生砧木苗为研究对象,研究不同嫁接方法和不同嫁接时间对成活率的影响。结果表明,随着浓硫酸浸泡时间的延长,膨胀率增加,浸泡45 min的皂荚种子发芽率最高;皂荚的成活率在不同嫁接方法和嫁接时间之间均存在显著差异,春季带木质部芽接的皂荚成活率最高。 相似文献
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介绍陇东水产养殖场从以甲鱼为主的生产系统,向多系统复合转变的经验。通过单一与复合生产经营形式经济效益的对比分析,为广大水产养殖工作者提供一条使生产步入良性循环的路子。 相似文献
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Daniel J Andrade Rosangela S Falconi Diego S Siqueira Crislany L Barbosa Antonio S Ferraudo Carlos AL Oliveira 《Pest management science》2013,69(1):81-87
BACKGROUND: Leprosis is one of the most serious citrus plant diseases. Leprosis‐affected plants, especially sweet orange [Citrus sinensis (L.) Osbeck], which is the most widely cultivated citrus fruit worldwide, show reduced photosynthetic capacity and severe defoliation. The aim was to evaluate the relationship between the Brevipalpus phoenicis (Geijskes) vector mite and citrus leprosis disease in Pera sweet orange plants grafted on different rootstocks. Data were analysed using numerical classification and conventional statistical analysis (ANOVA). RESULTS: Both viruliferous and non‐viruliferous B. phoenicis populations increased in number on plants maintained at low soil water content. Among the evaluated rootstocks, Sunki mandarin proved least favourable for mite population increase. Furthermore, the viruliferous mite population increased more rapidly than the non‐viruliferous mite population. CONCLUSION: The Cleopatra rootstock showed low variability in leaf nitrogen content, low mite number and low leprosis severity, thereby producing the most favourable results. Under appropriate moisture conditions, the Sunki rootstock produced the best results, showing the least severe leprosis. Rangpur lime rootstock grown in soil with varying water content showed the greatest variation in foliar nitrogen content, mite number and severity of leprosis and is considered to be the most difficult rootstock to manage. Copyright © 2012 Society of Chemical Industry 相似文献
996.
José Antônio Quaggio Thais Regina Souza Fernando César Bachiega Zambrosi Rodrigo Marcelli Boaretto Dirceu Mattos Jr. 《植物养料与土壤学杂志》2014,177(3):404-411
The fertigated area of the Brazilian citrus industry has grown rapidly during recent years, and an efficient management of nitrogen (N) application at these sites is required for sustainable citrus production. Therefore, a field trial with Valencia orange trees [Citrus sinensis (L.) Osbeck] on Swingle citrumelo rootstock (Citrus paradise Macfad. x Poncirus trifoliata L. Raf.) was conducted for 8 years to evaluate the effects of N rates (80, 160, 240 and 320 kg ha–1 y–1) applied by fertigation, either as ammonium nitrate (AN) or calcium nitrate (CN), on soil solution dynamics, fruit yield, nutritional status, and N‐use efficiency (NUE) of trees. The maximum fruit yield was reached with 240 kg N ha–1 for AN, whereas a linear response and greater fruit yield was observed for N supplied as CN. The NUE was reduced for both N forms with increasing N rates. However, the NUE for CN was 14 to 38% greater than the NUE for AN. The lower fruit yield and NUE for AN compared to CN‐treated trees was associated with the increased acidification of the soil solution with increased AN rates (pH ≤ 4.0). This limited nitrification resulted in a high ammonium (NH$ _4^+ $ ) concentration in the soil solution and a reduction in the net absorption of cations by the trees, particularly calcium (Ca). Due to the improved ion balance as well as the higher pH of the soil solution (pH ≥ 6.3) and diminished NH$ _4^+ $ availability, gains in both fruit yield and NUE in fertigated citrus groves in tropical soils can be obtained with the use of CN as a source of N. 相似文献
997.
Effects of organic and other management practices on soil nematode communities in tea plantation: a case study in southern China 总被引:1,自引:0,他引:1 下载免费PDF全文
Xingyue Li Qizhi Liu Zhilong Liu Wangpeng Shi Daowei Yang Eustachio Tarasco 《植物养料与土壤学杂志》2014,177(4):604-612
Four major tea management practices (organic, pollution‐free, conventional, and semi‐natural) are employed in Chinese tea plantations at present. These practices can induce changes in the physiochemical parameters, microorganism community and enzyme activity in tea plantation soil. However, understanding of their effects on soil nematodes is still scarce. This study aimed to investigate whether and how different management practices affect the biodiversity, function, and structure of soil nematode communities in tea plantation habitats. The soil nematode community structures and ecological indices were determined from the soil samples collected more than 6 y after their respective farming practices were first applied, and different management practices did not greatly affect soil nematode community evenness or species diversity, but organic practice increased nematode trophic diversity, common species diversity, and species richness. Pollution‐free practice considerably increased fungivorous nematodes, and both pollution‐free and conventional practice decreased bacterivorous nematodes markedly in the subsurface layers of soil. Predator and omnivorous nematodes were found to be more abundant in semi‐natural plantation. Organic practice was more sustainable and suitable for tea cultivation, with the greatest biodiversity, best nutrient conditions, higher and more stable C/N ratio and lower interference in the food web. 相似文献
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为揭示决定老枞水仙茶“枞味”的关键香气成分和关键性生化成分物质,应用气相-离子迁移谱技术(GC-IMS)、高效液相色谱法(HPLC)对不同香型老枞水仙的挥发性物质、主要理化成分进行特征分析。试验共鉴定出38种挥发性物质。木质味老枞水仙特征性香气成分是戊醛、己醛;青苔味老枞水仙特征性香气成分是3-己烯-1-醇单聚体和二聚体、芳樟醇单聚体;粽叶味老枞水仙特征性香气物质是2-戊基呋喃、苯甲醛。另外,生化成分中水浸出物、咖啡碱的增加对老枞水仙茶“枞味度”品质的提升有显著的积极作用,酯型儿茶素含量的增加将造成老枞水仙茶滋味品质的下降。特别值得注意的是,儿茶素品质指数的降低,对老枞水仙茶“枞味”的进一步提升有积极作用。本研究可实现老枞水仙的快速判别,为制定老枞水仙企业标准提供科学依据。 相似文献