Tag Archives: diversity

xxx M. Welc, A. Lundkvist, N-E. Nordh and T. Verwijst
Weed community trajectories in cereal and willow cultivations after termination of a willow short rotation coppice
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Weed community trajectories in cereal and willow cultivations after termination of a willow short rotation coppice

M. Welc*, A. Lundkvist, N-E. Nordh and T. Verwijst

Department of Crop Production Ecology, Swedish University of Agricultural Sciences, P.O. Box 7043, SE-750 07 Uppsala, Sweden
*Correspondence: Monika.Welc@slu.se

Abstract:

According to guidelines for willow short rotation coppice (SRC), weeding is needed during establishment, while weed populations which develop later under a well-established willow canopy do not require control. However, farmers are concerned that weeds which develop in SRC may result in long-lasting weed infestations in succeeding crops after SRC termination. We assessed the effects of two SRC-termination methods (with shallow and deep soil cultivation) on the development of the weed flora in a cereal system (CS) and in SRC during six seasons. Richness, ground cover, life-cycle strategy and composition of the weed species, and their environmental requirements (inferred from Ellenberg index) were evaluated.
SRC-termination method had no effect on the weed community trajectories in the succeeding SRC and CS. However, cropping system and growing season had significant impacts on species richness, ground cover and composition of the weed flora.
Differences in weed communities over time and between cropping systems were related to the impact of cropping systems on factors such as light, soil moisture, nitrogen level, and soil reaction, as inferred from the Ellenberg index. After termination of the old willow cultivation, the weed flora of the SRC and CS rapidly diverged and approached the weed flora characteristic for old willow stands and non-weeded old cereal plot, respectively. We conclude that willow stands can be converted, regardless of termination method, either into willow or cereal cultivations without additional risk of weed infestations other than those specific for their respective cropping systems. Furthermore, willow cultivations in agriculture contribute to floristic diversity at the landscape scale.

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785-792 E. Demjanová, M. Macák, I. Dalovic, F Majerník, Š. Týr, J. Smatana
Effects of tillage systems and crop rotation on weed density, weed species composition and weed biomass in maize
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Effects of tillage systems and crop rotation on weed density, weed species composition and weed biomass in maize

E. Demjanová¹, M. Macák¹, I. Dalovic,² F Majerník¹, Š. Týr¹, J. Smatana¹

¹Department of Sustainable Agriculture and Herbology, Faculty of Agrobiology and Food
Resources, Slovak Agricultural University in Nitra, Tr. A.Hlinku 2, 949 76 Nitra,
Slovak Republic, milan.macak@uniag.sk 2Institute of Field and Vegetable Crops, Novi Sad, Serbia, maizescience@yahoo.com Department of Sustainable Agriculture and Herbology, Faculty of Agrobiology and Food
Resources, Slovak Agricultural University in Nitra, Tr. A.Hlinku 2, 949 76 Nitra,
Slovak Republic, milan.macak@uniag.sk
²Institute of Field and Vegetable Crops, Novi Sad, Serbia, maizescience@yahoo.com

Abstract:

The field study was conducted over seven years in south-western Slovakia to investigate the effects of different soil tillage intensities and crop rotation on weed density, weed diversity and weed dry biomass in maize. Three basic tillage treatments were the following: mouldboard ploughing to a depth of 0.30 m (conventional tillage); offset disc ploughing to a depth of 0.15 m followed by combined cultivator; twice shallow loosening to a depth of 0.10 m (both reduced tillage). Annual broadleaf weeds (17 species) were clearly the dominant weed group under all soil tillage treatments, compared to perennial weeds (6 species) and annual grassy weeds (4 species). Dominant weed species were Amaranthus retroflexus and A. powelli, Chenopodium album, Echinochloa crus–galli, Convolvulus arvensis and Cirsium arvense. The number of species of the annual broadleaf and grassy weeds group was insignificant in conventional tillage and reduced tillage systems. Total weed density was significantly lower under the conventional tillage than the other reduced tillage systems. The main benefit of conventional tillage is a highly significant decline of perennial weeds. Only 2.6 perennial weed plants per quadrant in conventional tillage as compared to 7.5–9.0 in reduced tillage treatments were noted. Significantly less weed dry biomass was found in conventional treatment under mouldboard ploughing as compared to reduced tillage. Crop rotation did not have a significant influence on variability of species richness expressed according to Margalef’s index in maize. Tillage system was more influential than crop rotations on the weed density and diversity and weed biomass.

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156-161 O. Auškalnienė and A. Auškalnis
The influence of tillage system on diversities of soil weed seed bank
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The influence of tillage system on diversities of soil weed seed bank

O. Auškalnienė and A. Auškalnis

Lithuanian Institute of Agriculture,Instituto Alėja 1, LT – 58344, Akademija, Kėdainiai distr.;e-mail: ona@lzi.lt

Abstract:

Field experiments with different soil tillage systems were conducted in 2003–2006 at the Lithuanian Institute of Agriculture. Investigations to evaluate effects of soil tillage regime on weed seed bank and distribution in the soil layers were made after four years of experimentation. A total of 17 weed species were found in the soil seed bank; 98 % – annual dicotyledonous. The most abundant weed species in the seed bank were Chenopodium album, Lamium purpureum and Stellaria media. The highest number of weed seed species was found in treatments with reduced and no-tillage treatments in a soil layer of 0–5cm. In deeper soil layers, 5–10, 10–20, no differences in species number of weed seeds were found.

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