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Ammonium-conlaining fertilizers such as granular limestone ammonium nitrate (LAN) and liquid ammonium nitrate (AN) proved to be most elfective in stimulating germination and emergence of wild oat in sandy and loamy soil. In pot experiments, rates as low as 25 kg N ha ', significantly increased seedling emergence of wild oat. In sandy soil percentage emergence increased with increasing levels of LAN-fertilizer up to 1 25 kg N ha ' which gave 16-1 % emergence after 60 days. In control pots where no nitrogen was applied, only 21-6% of seeds planted emerged after 60 days. In loamy soil, as for AN in both soil types, high levels of LAN initially delayed seedling emergence. This negative effect disappeared approximately 15 days after seeding, resulting in no significant difference in emergence of wild oat where 25 to 125 kg N ha ' was applied as LAN or AN. All these rates, however, increased seedling emergence between 25 and 35'^ compared to the no-nitrogen treatments. Since the same rate of ammonia gas is not equally effeetive in breaking dormancy of semi-and deeply dormant wild oat seed, results of Ihese experiments are not necessarily applicable to wild oat seeds differing in dormancv status. Les effcis des engrais azotes sur la germlnution ct la k'vee des plantules de folles avoines (A. fatua L.) dans differents types de solsDes engrais contenant de Tammoniac comme les granules grcseux-ammo-nitrate (LAN) et les liquides amnio-nitratc (AN) ont demontre qu'ils etaient les stimulants les plus efficaces de la germination et de la levee des folles avoines dans les sols sableux et riches en matieres organiques. Dans unc experimentation en pot, des niveaux aussi bas que 25 unites N ha '. ont augmentes signiticativemcnt la levee des plantules dc folle avoine. Dans les sols sableux le pourcentage de levee augmente avee les doses croissantes d'engrais LAN jusqu'a 125 U.N. ha ' qui aboutit a line levee de 76.1 "A, apres 60 jours. Dans des sols riches en malieres organiques, et pour AN dans tes deux types de sots, des hauts niveaux d'azote retardent d'abord la levee des plantules. Cet effet negatif disparait approximativement 15 jours aprcs le semis, aboutissant a aucune difference significative dans la levee des iblles avoines entre 25 et 125 kg N ha ' tant pour LAN que AN. Toutes ces doses, en revanche, augmentent la levee de plantules entre 25 et 35"',, par rapport aux parcelles ne recevanl pas d'azote. Attendu que le meme nivcau de gaz ammoniac n'est pas egalement efficace pour lever la dormance des graines de folles avoines semi-ou profondement dormantes, les resultats de ces essais nc sont pas necessairement applicables a des graines de folles avoines de statuts de dormance differents.Die Wirkung ran Slickstoffdungemitteln in verschiedenen Bodenarten auf die Keiniung und den IVuc/i.s der Keimpfian^en des Ftug-Hafers (Avena fatua L.)

The effect of fermentation (30°, 34°, 38°and 42°C) and drying temperatures (40°, 50°, 60°and 70°C), as well as the effect of controlled drying as opposed to sun-drying on rooibos tea quality were investigated. The quality of rooibos tea improved with increasing fermentation temperature whereas quality decreased with increasing drying temperature (P Ͻ 0.05). No significant subjective quality difference between the two drying methods was obtained. Tea dried under controlled conditions was lighter in colour than sun-dried rooibos tea (P ϭ 0.003) as indicated by higher L* values. The chromaticity parameters (a* and b*) were not significantly affected by drying under controlled conditions. Less chlorophyll was present in sun-dried tea than in tea dried under controlled conditions. The colour of tea prepared under experimental conditions was comparable with the colour of commercially-produced rooibos tea samples.