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SO2对灰霉葡萄孢和交链孢的抑制作用 总被引：1，自引：1，他引：0
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N. T. Donkor R. J. Hudson E. W. Bork D. S. Chanasyk M. A. Naeth 《Journal of Agronomy and Crop Science》2006,192(3):192-200
We conducted a 2‐year study in central Alberta to quantify and simulate the soil water status of boreal grasslands under three grazing systems using wapiti (Cervus elaphus Canadensis), viz. (1) ungrazed control (UNG), (2) high intensity [4.16 animal unit month per ha (AUM) ha?1 ] short‐duration grazing (SDG) and (3) moderate intensity (2.08 AUM ha?1) continuous grazing (CG). Soil water was measured from May 1997 to September 1998 to a depth of 15 cm. Total annual precipitation in 1997 and 1998 was 494 and 429 mm respectively. In both years grazing treatments reduced soil water. Soil water content under SDG was significantly (P < 0.05) lower than CG. Simulation of soil water on each grazing system was conducted using PASTURE, a simple compartmental system dynamics model. Evaluation of the model was conducted using statistical criteria that included calculation of average error, root mean square, coefficient of residual mass and modelling efficiency and comparing these statistics against optimal values. Although the model under‐predicted soil water, simulations of soil water for grazing treatments in both years were closest to measured values with modelling efficiency (how well observed values are close to simulated values) up to 68 %. 相似文献
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The results of a study of the streptococcal fibrinolysin reaction and its inhibition by sera containing specific antibody are presented. It was possible to devise a quantitative antifibrinolysin test by controlling the various factors influencing the reaction. In man, the antifibrinolysin response was found to vary according to the strain of streptococcus responsible for the infection. 相似文献
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油桐早实丰产技术研究报告 总被引：1，自引：0，他引：1
油桐早实丰产国家攻关专题协作组 《经济林研究》1992,10(2):1-14
油桐早实丰产技术的研究是“七五”国家科技重点攻关项目。项目要求从1986年至1990年的5年内完成油桐丰产试验林面积2000亩,从第三年开始亩产桐油2-3kg,进入盛果期亩产桐油20-25kg。经6年的努力,实际完成丰产林面积2037.5亩,超额1.7％。从1988年至1991年4年累产桐油89932.8kg,连同林地间种总收入是582208.6元,扣除科研投资30万元(地方资助5万元),盈余28万元。丰产林产生的辐射效应,带动农户造桐林1万余亩。每亩多增收30元,则有30万元。油桐早实丰产技术研究,不仅为油桐生产提供应用技术,并且也直接创造了经济效益。本课题所营造的丰产林获得成功的关键技术是实现了栽培良种化,应用立地类型划分的方法。正确选择宜桐林地,合理调整林分结构,运用生态系统的理论和方法,集约化经营好桐林,这是丰产的保证。同时在试验研究的全过程中,贯彻执行了正确的科研指导思想和技术路线。 相似文献
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Feeding pelteobagrus fulvidraco
in cyclic-water tank with six different feeds over aperiod of sixty days.The results are
shown as follows1.The frequency of occurrence of the foods on the stomach of pelteodagrus
fulvidracocomplete feedI,I,Sliver carp meat＞pond-snail meat,pig meat＞mud-fish
meat,complete feed II.Inthe case of the growth,similar changes arenoticed.2.After
feeding,the protease and diastase activities of stomach and intestine show asignificant
rising(p＜0.05).3.The oxygen consumption rate of pelteobagrus fulvidraco is144mg/h.kg,and
increases by 13.8%than before trial,suffocation point is0.309mg/l(p＞0.05). 相似文献
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Within boreal grasslands, little information exists on the effects of initial defoliation date, frequency, and intensity on accumulated herbage yield and quality. We investigated the effects of initial defoliation in May, June or July, at heights of 5, 10 or 15 cm, and repeated at 2‐, 4‐ or 6‐week intervals throughout the growing season. Harvested material was combined with year‐end residual biomass, and examined for herbage removed, crude protein (CP), crude protein yield (CPY) and neutral detergent fibre (NDF). Compared to single defoliated check plots, total, grass and forb dry matter (DM) yields were lower under repeated defoliation by 25, 38 and 17 %, respectively. The majority of total herbage produced was harvested in the spring clipping. Total, grass and forb DM yields peaked under moderate (10 cm) clipping. Total DM and grass biomass were maximized with long (6 week) recovery periods. In contrast, forb biomass was greatest with May defoliation followed by a 4‐week interval. While maximum grass CPY was found under 10‐cm defoliation, forb CPY peaked with early and moderate to intensive defoliation. These results indicate that season‐long herbage biomass, along with CPY, can be maximized in boreal grasslands through controlled defoliation. 相似文献
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植物次生物质对棉铃虫谷胱甘肽S－转移酶和乙酰胆碱酯酶的影响 总被引：2，自引：0，他引：2