Spatial patterns, species richness and cover in weed communities of organic and conventional no-tillage spring wheat systems

The ecological significance of species diversity within agroecosystems has become a point of interest in recent years. Although the time and spatial scale at which diversity is measured may influence the interpretation of its functional importance, little research has been conducted on methodological approaches to assess the number and relative abundance of agricultural plant species. In this study, we (1) evaluated the applicability of the species-area curve to examine plant species richness and α and β diversity in conventional no-tillage and organically managed spring wheat systems, and (2) assessed temporal changes in plant species richness across systems. Measurements were obtained at three times during two growing seasons in experimental plots and at three times during one growing season on commercial farms in Montana. In accordance with previous studies, management system affected species richness and diversity. In eight of nine studied cases, we detected a positive relationship between species richness and sampled area. In these eight cases, intercepts (α diversity) were higher for the organic systems than for the conventional no-tillage systems. Slopes (β diversity) were higher for the organic system in six of nine cases studied. Species richness declined as the season progressed for both systems, with the organic systems consistently having more species than the conventional no-tillage systems. Despite differences in the species composition and between the experimental plots and commercial farm field size, the patterns of species richness and α and β diversity were relatively constant, suggesting that the processes responsible for the assembly of plant communities in agroecosystems of the Northern Great Plains are similar at a range of spatial scales.

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Diversity of weed communities in soybean [Glycine max (L.)] crop growing under direct sowing depending on cover crops and different herbicide doses

Acta Agrobotanica ◽

10.5586/aa.1698 ◽

2016 ◽

Vol 69 (4) ◽

Author(s):

Elżbieta Harasim ◽

Cezary Andrzej Kwiatkowski ◽

Małgorzata Haliniarz ◽

Paweł Harasim ◽

Magdalena Gocół

Keyword(s):

Species Richness ◽

Oilseed Rape ◽

Cover Crops ◽

Agricultural Land ◽

Agricultural Landscapes ◽

Winter Rye ◽

No Tillage ◽

Winter Oilseed Rape ◽

Soybean Crop ◽

Weed Communities

Despite being harmful for agricultural production, weeds are an essential component of biodiversity in agricultural landscapes. A field study was conducted during the period 2007–2009 on grey-brown podzolic soil (sandy), designated as PWsp, with the granulometric composition of silt and classified Class 2 in agricultural land suitability. The study evaluated the structure of weed communities based on selected indicators of diversity of a soybean crop grown under no-tillage with mulch from winter rye, winter oilseed rape, and white mustard as well as using herbicide rates reduced by 25% and 50% in relation to the standard rate (2 L ha−1). The studied factors were as follows: (i) mulch plant species and mulch management method; (ii) rates of the foliar herbicide Basagran 600 SL (a.i. bentazon; 600 g L−1). The results of this study confirm that no-tillage with mulch significantly changes the diversity of weed flora in a soybean crop. Among the mulches used, the mowed rye and winter oilseed rape in particular increased the values of the general diversity (H'), species richness (d), and evenness (J') indices relative to the control treatment. On the other hand, the study found a strong decrease in the value of the dominance index (c). Reduced herbicide rates modified only the species richness index, in the case of which the 75% rate resulted in its significantly higher values compared to the full rate.

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The Effect of Different Soil Tillage Systems and Crop Residues on the Composition of Weed Communities

Agronomy ◽

10.3390/agronomy11071276 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1276

Author(s):

Vaida Steponavičienė ◽

Aušra Marcinkevičienė ◽

Lina Marija Butkevičienė ◽

Lina Skinulienė ◽

Vaclovas Bogužas

Keyword(s):

Soil Ph ◽

Crop Residues ◽

Soil Tillage ◽

Reduced Tillage ◽

Plant Residues ◽

No Tillage ◽

Agricultural Crops ◽

Weed Species ◽

Tillage Systems ◽

Weed Communities

The composition of weed communities in agricultural crops is dependent on soil properties and the applied agronomic practices. The current study determined the effect of different tillage systems and crop residue on the soil weed community composition. The research programme encompassed 2013–2015 in a long-term field experiment located in the Experimental Station of Vytautas Magnus University in Lithuania. The soil type in the experimental field was qualified as Endocalcaric Stagnosol (Aric, Drainic, Ruptic, Amphisiltic). Weeds were categorised into communities according to soil pH, nitrogen and moisture indicators. The results of investigations were grouped using cluster analysis. Agricultural crops were dominated by different weed species depending on the soil pH and moisture. Weed species were relatively more frequent indicating nitrogen-rich and very nitrogen-rich soils. In the reduced tillage and no-tillage systems, an increase in the abundance of weed species indicating moderate acidity and low acidity, moderately wet and wet, nitrogen-rich and very nitrogen-rich soils was observed. The application of plant residues decreased the weed species abundance. In the reduced tillage and no-tillage systems, the quantitative distribution of weed was often uneven. By evaluating the association of weed communities with groups of different tillage systems with or without plant residues, their control can be optimised.

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The effectiveness of weed regulation methods in spring wheat cultivated in integrated, conventional and organic crop production systems

Journal of Plant Protection Research ◽

10.2478/v10045-012-0078-4 ◽

2012 ◽

Vol 52 (4) ◽

pp. 486-493 ◽

Cited By ~ 3

Author(s):

Beata Feledyn-Szewczyk

Keyword(s):

Spring Wheat ◽

Crop Production ◽

Dry Matter ◽

Production Systems ◽

Integrated System ◽

Integrated Systems ◽

Conventional System ◽

Weed Species ◽

Organic System ◽

Weed Communities

Abstract The research was conducted from 2008 to 2010, and compared the influence of different weed control methods used in spring wheat on the structure of the weed communities and the crop yield. The study was carried out at the Experimental Station of the Institute of Soil Science and Plant Cultivation - State Research Institute in Osiny as part of a long-term trial where these crop production systems had been compared since 1994. In the conventional and integrated systems, spring wheat was grown in a pure stand, whereas in the organic system, the wheat was grown with undersown clover and grasses. In the conventional system, herbicides were applied two times in a growing season, but in the integrated system - only once. The effectiveness of weed management was lower in the organic system than in other systems, but the dry matter of weeds did not exceed 60 g/m2. In the integrated system, the average dry matter of weeds in spring wheat was 4 times lower, and in the conventional system 10 times lower than in the organic system. Weed diversity was the largest in spring wheat cultivated in the organic system. In the conventional and integrated systems, compensation of some weed species was observed (Viola arvensis, Fallopia convolvulus, Equisetum arvense). The comparison of weed communities using Sorenson’s indices revealed more of a similarity between systems in terms of number of weed species than in the number of individuals. Such results imply that qualitative changes are slower than quantitative ones. The yield of grain was the biggest in the integrated system (5.5 t/ha of average). It was 35% higher than in the organic system, and 20% higher than in conventional ones.

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The role of time and species identities in spatial patterns of species richness and conservation

Conservation Biology ◽

10.1111/cobi.12716 ◽

2016 ◽

Vol 30 (5) ◽

pp. 1080-1088 ◽

Cited By ~ 12

Author(s):

Judi E. Hewitt ◽

Simon F. Thrush ◽

Kari E. Ellingsen

Keyword(s):

Species Richness ◽

Spatial Patterns

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Spatial patterns and sampling plans for cereal aphids [Hom.: Aphididae] killed by entomophthoralean fungi and hymenopterous parasitoids in spring wheat

Entomophaga ◽

10.1007/bf02372427 ◽

1992 ◽

Vol 37 (2) ◽

pp. 265-275 ◽

Cited By ~ 10

Author(s):

M. -G. Feng ◽

R. M. Nowierski

Keyword(s):

Spatial Patterns ◽

Spring Wheat ◽

Cereal Aphids ◽

Sampling Plans

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Spatial distribution of the macrozoobenthos in the Solís Grande Stream estuary (Canelones-Maldonado, Uruguay)

Brazilian Journal of Biology ◽

10.1590/s1519-69842001000300010 ◽

2001 ◽

Vol 61 (3) ◽

pp. 409-420 ◽

Cited By ~ 21

Author(s):

P. MUNIZ ◽

N. VENTURINI

Keyword(s):

Cluster Analysis ◽

Spatial Distribution ◽

Species Richness ◽

Spatial Patterns ◽

Fine Sand ◽

Present Species ◽

Multivariate Techniques ◽

Natural Factors ◽

Mean Diameter ◽

Variation Explained

The analysis of 24 quantitative macrobenthic samples taken from the Solís Grande Stream estuary yielded 10 species from a total of 4,446 individuals. It was verified that both species richness and diversity was lower than those recorded in nearby regions with similar environmental conditions. In contrast with other studies, a marked dominance of any of the present species was not verified. All the species recorded correspond to typical estuarine organisms. Abundance data were analysed with multivariate techniques and the results showed a relationship with salinity, mean diameter and the percentage of fine sand. According to the cluster analysis and the canonical correspondence analysis (CCA) four groups of stations were defined. The partition out of total variation of the species data showed that the amount of variation explained by the space alone was low. Spatial patterns observed and their possible causes are analysed and discussed in relation to the natural factors that acts in this coastal ecosystem.

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Metabolic asymmetry and the global diversity of marine predators

Science ◽

10.1126/science.aat4220 ◽

2019 ◽

Vol 363 (6425) ◽

pp. eaat4220 ◽

Cited By ~ 21

Author(s):

John M. Grady ◽

Brian S. Maitner ◽

Ara S. Winter ◽

Kristin Kaschner ◽

Derek P. Tittensor ◽

...

Keyword(s):

Species Richness ◽

Spatial Patterns ◽

Marine Mammals ◽

Phylogenetic Diversity ◽

Latitudinal Gradient ◽

Latitudinal Gradients ◽

Competitive Interactions ◽

Marine Predators ◽

Theoretical Predictions ◽

The Tropics

Species richness of marine mammals and birds is highest in cold, temperate seas—a conspicuous exception to the general latitudinal gradient of decreasing diversity from the tropics to the poles. We compiled a comprehensive dataset for 998 species of sharks, fish, reptiles, mammals, and birds to identify and quantify inverse latitudinal gradients in diversity, and derived a theory to explain these patterns. We found that richness, phylogenetic diversity, and abundance of marine predators diverge systematically with thermoregulatory strategy and water temperature, reflecting metabolic differences between endotherms and ectotherms that drive trophic and competitive interactions. Spatial patterns of foraging support theoretical predictions, with total prey consumption by mammals increasing by a factor of 80 from the equator to the poles after controlling for productivity.

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