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Regulation weedy plants in a growth of winter rape
KAMEŠ, Josef
This work is focused on the problems of weed plants in winter rape which has been in recent years one of the most significant crop-plants in the world and represents one of the few plants grown in the Czech Republic where we can expect positive profit. The problems of weed plants is one of the main negative factors affecting the yield and quality of rape. For this reason I was following the weed infestation rate in three variants in one land during a certain vegetation period of winter rape. The number of weed plants occurred in the given land was recorded and assessed regularly. The most frequent weed was field pansy, which made up approximately 85 % of all the range of weeds which occurred in the explored land. The second most frequent weed was Field pennycress which made up 14 % of the weeds occurred. There were hardly any other kinds of weeds in the land. From the resultant values we can make the conclusion that long-term fight against persistent weeds has to be done carefully and has to be based on complex protection which consists of preventive and direct methods of weed plants regulation.
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Comparison choice cultural and weed kinds form stock Amaranthus
VÁLEK, Jan
Amaranthus (L.) belongs to among old cultural crops. Cultural forms of some species were already grown by Aztecs and Incs in ancient times. High nutritive value of seeds redounded to rediscovery of the crops. Tested varieties of cultural amaranth get to the interaction whit wild species of amaranth. This work would had contribute to better knowledge of ecology in the hybrid of cultural variety and weed (A. x turicensis = A. cruentus x A. retroflexus) The aim of this work was to describe production and morphometric characteristics of selected relative cultural and weed species of amaranth (Amaranthus hypochondriacus, Amaranthus cruentus, Amaranthus retroflexus), the hybrid A. x turicensis and to determinate occurrence and survival of weed species A. retroflexus onplaces, where cultural amarant was grown. A. retroflexus shows as a very resistant to damage. Cultural species responded on damage by reduction of majority observed parameters. Cultural species of amaranth responded more on different conditions substrate than the weed species. Response of hybrid on different substratum conditions was in the middle of spectrum of the response in cultural parents and the weed species. Indiference of the hybrid to substrate should be better clear up in the next studies. Weed species is little sensitive to competicion and his characteristics (total biomass, legth inflorescence, height of plants, number of leaves) are different not much. Effect of competition on hybrid shows his non - uniform response probably caused by his considerable variability Absence of cultural amarant and interspecific hybrids shows on relation of these plants to warmer weather that is probably the main factor for their occurrence.
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