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41.
42.
We evaluated the re-establishment of an Italian ryegrass pasture by self-seeding on a no-till integrated crop-livestock systems (ICLS) in the southern region of Brazil. This work is part of a long-term experimental protocol initiated in 2003. We tested the effects of various management practices, such as summer crop systems (soybean vs. maize–soybean rotation), stocking methods (continuous vs. rotational) and grazing intensities (low vs. moderate), on Italian ryegrass pasture establishment. In addition, we tested resilience of the system by testing pasture's ability to re-establish following a year without seed head production. The experiment consisted in the rotation, on the same area, of Italian ryegrass pasture grazed by sheep during the winter and up to the end of the grass production cycle, and soybean or soybean-maize grain crops rotation cultivated during the summer. The pasture established itself by self-seeding since 2005. Data were collected in 2011 and 2012 stocking season. The soybean summer crop, continuous stocking and low grazing intensity, all positively affected the production of reproductive tillers in 2011. Grazing intensity in 2011 strongly influenced early vegetative tiller densities (before crop harvest) in 2012. However, none of the grazing intensity or the stocking method treatments affected herbage mass at the end of pasture establishment in 2011 or 2012. On the other hand, the soybean summer crop positively affected pasture establishment, both in term of tiller densities and herbage mass at the end of pasture establishment. The removal of all seed heads in 2011 (preventing seed production) resulted in the total failure of pasture establishment in 2012. Overall, Italian ryegrass establishment by self-seeding relies on the annual replacement of the soil seed bank. This experiment demonstrated that under various stocking methods, moderate grazing intensity and maize or soybean summer crop, Italian ryegrass pasture establishment by self-seeding remains successful even when the stocking periods extended up to the end of the grass production cycle. Self-seeding with moderate grazing intensity ensures successful pasture establishment, reduces labour and costs and allows to increase the stocking period and so animal live weight gain over the grazing season. 相似文献
43.
相变材料能够储存或释放显热,在熔化或凝固过程中虽然温度不变但吸收的潜热却相当大。根据相变材料可以吸收环境热能并在需要时向环境发出热能的特征,研究相变材料在粮食仓储中的应用,减小外界环境对粮仓温度的影响,达到恒温绿色生态储粮的目的。 相似文献
44.
为探究圆柏(Sabina chinensis)的化感作用,本研究采用培养皿滤纸法研究圆柏叶片浸提液对地肤(Kochia scoparia)、稗草(Echinochloa crusgalli)、藜(Chenopodium album)、反枝苋(Amaranthus retroflexus)、马齿苋(Portulaca oleracea)5种杂草种子和向日葵(Helianthus annuus)、燕麦(Avena sativa)、油菜(Brassica campestris)、荞麦(Fagopyrum esculentum)4种作物萌发和生长的影响,并用圆柏叶片、树枝、树皮粉末和浸提液进行盆栽抑草效果检测。结果表明:圆柏叶片浸提液对5种杂草种子萌发和幼苗生长具有显著的抑制作用,对地肤、藜、反枝苋萌发及生长的化感效应指数均在-0.98以上;盆栽抑草结果表明,圆柏不同部位对5种杂草种子萌发和稗草及反枝苋株高生长均有较好的抑制作用,叶片化感强度大于树皮和树枝,叶片粉末拌土处理抑草效果好于浸提液叶面喷施;对作物的化感作用结果表明,圆柏叶片浸提液稀释1.5倍时,抑制荞麦种子萌发但不影响其株高及根生长,不影响燕麦种子萌发但降低其株高和根长生长,抑制油菜的发芽势和发芽指数但不影响其种子萌发率,促进油菜株高及根长生长,不影响向日葵种子萌发和生长。综上所述,圆柏具有良好的抑草活性,对作物影响较小。 相似文献
45.
UV-C处理对甘薯贮藏品质的影响 总被引:1,自引:0,他引:1
以海南桥头产区的“高系14”甘薯为材料,分别进行10、20、30 min的UV-C照射处理,统计甘薯贮藏60 d内的腐烂率、失重率和发芽率,并同时记录5种生理指标的变化,以探讨UV-C处理对甘薯贮藏品质的影响。结果表明:UV-C处理显著降低了甘薯贮藏期间的腐烂率,但同时促进了发芽,而对失重率无显著影响。生理指标方面,30 min的UV-C照射提高了可溶性蛋白的积累,减少可溶性固形物的损耗,并促进了POD、SOD和CAT的总体酶活性。综合来说,UV-C处理若要应用于甘薯贮藏保鲜,还需辅助使用其他的抑芽手段。 相似文献
46.
47.
48.
Blending Bacillus thuringiensis (Bt) corn and non-Bt corn seeds in the same bag is a convenient and easier compliance solution to satisfy refuge regulations. However, there has been considerable debate and concern about larval movement of the target insects in a seed blend because of its potential effect on the development of resistance. Reported here are studies to determine the larval movement of European corn borers, Ostrinia nubilalis (Hübner), in a seed blend compared to a structured refuge and their effects on survival, feeding injury and larval fitness. Also evaluated is the relative performance of a purple-seeded corn hybrid as a surrogate host plant for tracking gene flow. Seed blend and structured refuge arrangements of Agrisure GT/CB/LL Bt corn expressing Cry1Ab and isoline plants were evaluated at two locations in 2013 and 2014 by manually infesting refuge plants with first and second generation corn borer larvae. The majority of leaf and stalk injury was recorded on the refuge plant, which amounted to 66–83% of the total tunnel length. In both refuge arrangements, plant injury and the number of larvae recovered significantly decreased on neighboring plants with increasing distance away from the refuge plant in the same row. The relative decline in injury was much more pronounced in the seed blend, with neighbor Bt plants experiencing very minor tunneling or no injury at all due to the high dose trait. Eighty-nine percent fewer live larvae were also found on neighbor Bt plants in the seed blend compared to those found in the structured refuge plots. Larvae that moved to Bt plants as well as older instars that were manually placed on Bt plants failed to complete development. Comparison of the number of tunnels and larvae recovered per refuge plant indicated that the seed blend may not produce as many susceptible individuals as those produced in a structured refuge arrangement. Although the purple-seeded hybrid showed lower levels of ear and stalk injury, it could serve as an appropriate surrogate refuge plant to track gene flow. 相似文献
49.
高校图书馆保存本的改革 总被引:2,自引:1,他引:1
于向前 《农业图书情报学刊》2010,22(6):108-110
高校图书馆保存本必须改革。文章指出保存本存在的问题以及改革的必要性、措施和意义,改革的有效措施是变保存本为特色馆藏。 相似文献
50.
以解除休眠的水曲柳种子为材料,研究种子再干燥脱水贮藏的可行性。结果表明:已解除休眠的种子在室温条件下进行再干燥是可行的,干燥处理后种子的萌发率和平均发芽时间没有明显变化;但在5℃条件下再干燥是不可行的,干燥后种子萌发率、发芽指数显著下降,平均发芽时间明显延长。已解除休眠的种子在室温条件下再干燥处理后贮藏16个月内种子的萌发率没有显著变化,但随着贮藏时间的延长种子发芽指数显著下降,平均发芽时间显著延长。已解除休眠水曲柳种子再干燥贮藏后使用KT、GA3和乙烯利处理对种子的萌发都没有明显的促进作用。 相似文献