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41.
J Petersen 《Weed Research》2003,43(1):33-39
Summary The experiments were carried out in the two spring barley fields of the organic six-course cattle:crop rotation at Foulumgaard, Denmark. The weed density was 300 and 1800 plants m−2 respectively. Pig slurry was applied by hand in microplots by four methods: broadcasting followed by incorporation, or injected in bands to depths of 5, 10 or 15 cm. Spring barley and weeds were sampled separately six times during the tillering and elongation phase of the spring barley. The effect of application method on dry-matter (d.m.) production, nitrogen uptake and recovery of applied nitrogen in the spring barley and the weeds is reported. Slurry banding halved the weed d.m. and weed N uptake compared with broadcasting, irrespective of weed density. Weeds recovered up to 12% of the applied nitrogen, which made them a significant competitor when the slurry was broadcast and incorporated. Banding by direct injection reduced the slurry:soil contact and the weed:crop competition balance for applied nitrogen moved in favour of the crop. Thus, the crop recovery of applied nitrogen at the end of the sampling period was increased from approximately 45% for broadcast and incorporated to approximately 50% for injected slurry, and coincidental weed recovery was reduced to a maximum of 5%. As the nitrogen supply normally affects plant d.m. production, banding of slurry might well improve crop competitiveness and its tolerance to mechanical weed control. 相似文献
42.
N. J. Grünwald F. Workneh S. Hu A. H. C. van Bruggen 《European journal of plant pathology / European Foundation for Plant Pathology》1997,103(1):55-63
Testing of soil samples in greenhouse assays for suppressiveness to soilborne plant pathogens requires a considerable investment in time and effort as well as large numbers of soil samples. To make it possible to process large numbers of samples efficiently, we compared an in vitro growth assay with a damping-off assay using Pythium aphanidermatum as the test organism on tomato seedlings. The in vitro test compares the radial growth or relative growth of the fungus in soil to that in autoclaved soil and reflects suppressiveness of soils to the pathogen. We used soils from a field experiment that had been farmed either organically or conventionally and into which a cover crop (oats and vetch in mixture) had been incorporated 0, 10, 21, and 35 days previously. We obtained a significant, positive correlation between damping-off severities of tomato seedlings in damping-off assays and both relative and radial growth in vitro. In addition, radial and relative growth of P. aphanidermatum in the in vitro assay were positively correlated with several carbon and nitrogen variables measured for soil and incorporated debris. We did not find differences between the two farming systems for either growth measures of P. aphanidermatum or disease severities on tomato at different stages of cover crop decomposition. The in vitro assay shows potential for use with any fungus that exhibits rapid saprophytic growth, and is most suitable for routine application in suppressiveness testing. 相似文献
43.
内蒙河套灌区盐碱低产田建立有机质富积层改土培肥效果 总被引:1,自引:0,他引:1
通过连续四年在内蒙古河套灌区低产盐碱地定点、定位试验与定时测土分析,明确了土壤耕层增施有机物料建立有机质富积层,能够改善土壤理化性状,尤其是能降低土壤表层含盐量,提高作物保苗率和显著增加作物产出量。 相似文献
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试验选择处于热应激条件下的192只35周龄新罗曼褐壳蛋鸡,随机分为6组,分别饲喂添加0.10,20,30,40,50 g/t含铬量为7.410mg/kg的葡萄糖耐量因子(GTF)的玉米—豆粕型基础日粮52d。试验结束时随机抽取试验鸡36只(每组6只),取肾上腺称重并制作切片,研究有机铬对热应激蛋鸡肾上腺组织结构的影响。结果试验组肾上腺重量较对照组略有增加;热应激时蛋鸡肾上腺的肾间组织比例增大,肾间组织和嗜铬组织的细胞均有结构受损的现象;补铬使肾间组织比例减小,嗜铬细胞增多,细胞结构完好。 相似文献
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研究了以不同比例十六烷基三甲基溴化铵(CTMAB)单一修饰和十六烷基三甲基溴化铵 十二烷基磺酸钠(CTMAB SDS)混合修饰土娄土耕层对重金属镉离子吸附的影响,结果表明:吸附量顺序为耕层原土>50%CTMAB>100%CTMAB 20%SDS>100%CTMAB,温度升高,吸附量上升;最佳吸附等温线模型可以用BET模型描述,热力学参数的研究表明,吸附自发性与吸附量具有相同的变化规律,反应的焓变与熵变共同决定了反应的自发性。从热力学角度对修饰改性土娄土对Cd2 吸附的机理进行了探讨。 相似文献
49.
AIM: To investigate whether protein kinase C (PKC) is involved in the proliferation and the telomerase expression in human hepatocellular carcinoma cells. METHODS: Human hepatocellular carcinoma cells (BEL-7402) were treated with exogenous phorbol-12-myristate-13-acetate (PMA, PKC activator) and staurosporine (SP, PKC inhibitor) for 48 hours. The techniques of cell culture and the telomeric repeat amplification protocol silver staining in combination with computer image scanning system in vitro were used to observe the variations of the growth and the telomerase expression. RESULTS: The proliferative potential of BEL-7402 cells was decreased by the action of PMA as well as SP, and the telomerase expression was also inhibited by PMA and SP. CONCLUSION: Our findings suggest that the proliferation of human hepatocellular carcinoma cells and the telomerase expression may be related to PKC. 相似文献
50.
秀丽纤杆线虫 (Caenorhabditis elegans)是一种模式线虫 ,目前广泛应用于寄生性线虫基因的功能研究 ,并且还被用于捻转血矛线虫等寄生性线虫疫苗侯选抗原基因的表达和耐药性产生机制方面的研究 相似文献