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Dominant weeds in maize (Zea mays L.) cultivation and their competitiveness under conditions of various methods of weed control

100%

Glowacka A.

Acta Agrobotanica

2011

tom 64

nr 2

A field experiment was conducted in the years 2008- 2010 at the Research Station of the Faculty of Agricultural Sciences, University of Life Sciences in Lublin, on brown soil with a slightly acidic pH, a high content of available phosphorus and potassium as well as an average magnesium content. The experiment was set up in a random split-plot design with four replications, with two methods for controlling weed infestation: I. mechanical – weeding of inter-rows twice; II. chemical – the herbicide Afalon Dyspersyjny 450 SC (a.i. linuron, 900 g×ha-1). Next, potassium, calcium and magnesium contents were determined in maize and in the dominant weed species. Based on the dry weight yield of maize and the biomass of particular weed species, nutrient uptake per hectare area was calculated. The chemical method of weed control reduced both the number and dry weight of weeds more than the mechanical method. The dominant species in the maize crop were Echinochloa crus-galli (L.) P. Beauv., Chenopodium album L., Galinsoga parviflora Cav., and Cirsium arvense L. All the weed species examined were more competitive than maize in accumulating potassium, calcium and magnesium. Galinsoga parviflora Cav. was the most competitive species with maize for potassium, Cirsium arvense L. for calcium, and Chenopodium album L. and Polygonum lapathifolium L. subsp. lapathifolium for magnesium. Weeds are serious competitors in taking up nutrients relative to crop plants; their share in the total uptake of macroelements from the soil by the maize crop and weeds together was considerable and it averaged as follows: for K – 35%, Ca – 27.3%, Mg –27.4%.

Trade-off of sexual and asexual recruitment in a dominant weed Ligularia virgaurea (Maxim.) in Alpine grasslands (China)

100%

Wu G.-L., Hu T.-M., Liu Z.-H.

Polish Journal of Ecology

2010

tom 58

nr 1

Ligularia virgaurea (Maxim.) is a typical naturally-occurring native noxious weed, widely distributed in alpine grasslands of the Tibetan Plateau, China. Three field sampling plots (30 m ´ 50 m) dominated by L. virgaurea were selected to study its population colonization mode and the relationship between sexual- and clonalrecruitment in alpine meadow of the QinghaiTibetan Plateau, NW China. Field investigations were conducted on its soil seed bank, seed rain and the individuals of new recruitment (seedlings and ramets) to study its sexual and asexual recruitment. And, 46 individuals which produced the seeds were selected randomly to study their relationship between seed production and ramet production. Results showed that there were more ramets (26.23 ramets m⁻²) and less seedlings (6.70 seedlings m⁻²) and a mean value of seed rain was close to 8.04 seeds m⁻², but the soil seed bank for this species was not found in study sites. Significantly negative correlations (r = – 0.416, P <0.001) between seed number per individual and ramet number per adult individual were found for L. vrigaurea in studied alpine grasslands. Our results revealed that clonal reproduction was the main population colonization mode. In addition, there was a significantly negative relationship between seed production and ramets for this species.

Ograniczanie wyników

1 Acta Agrobotanica

1 Polish Journal of Ecology

1 Glowacka A.

1 Hu T.-M.

1 Liu Z.-H.

1 Wu G.-L.

1 2011

1 2010

Wyniki wyszukiwania

Dominant weeds in maize (Zea mays L.) cultivation and their competitiveness under conditions of various methods of weed control

Trade-off of sexual and asexual recruitment in a dominant weed Ligularia virgaurea (Maxim.) in Alpine grasslands (China)