Landscape Is the Main Driver of Weed Assemblages in Field Margins but Is Outperformed by Crop Competition in Field Cores

Weeds are considered a major pest for crops, and as such have been intensively managed by farmers. However, weeds, by providing resources, also support farmland biodiversity. The challenge for sustainable weed management is therefore to maintain weed diversity without compromising crop production. Meeting this challenge requires determining the processes that shape weed assemblages, and how agricultural practices and landscape arrangement affect them. In this study, we assess the effects of crop competition on weeds, nitrogen input, weed control and landscape on both weed diversity and abundance in the margins and centres of 115 oilseed rape fields in Western France. We show that weed assemblages in field cores were mainly shaped by crop height, a proxy of crop competition. By contrast, weed assemblages in field margins increased with the number of meadows in the landscape, revealing the role of spatial dispersal. Using structural equation modelling, we further show that in the field core, weed assemblages were also indirectly shaped by landscape through spatial dispersal from the field margin. Overall, our study gives empirical support for crop competition as a way to reduce the intensity of chemical weeding, and for meadows as a way to enhance biodiversity in the landscape.

Download Full-text

Weed Management in Small Grains Harvested for Grain

EDIS ◽

10.32473/edis-wg009-2020 ◽

2020 ◽

Vol 2020 (3) ◽

Author(s):

Jason Ferrell ◽

Gregory MacDonald ◽

Pratap Devkota

Keyword(s):

Weed Control ◽

Weed Management ◽

Chemical Control ◽

Management Practices ◽

Good Management ◽

Small Grains ◽

Crop Competition

Successful weed control in small grains involves using good management practices in all phases of production. In Florida, winter weeds compete with small grains for moisture, nutrients, and light, with the greatest amount of competition occurring during the first six to eight weeks after planting. Weeds also cause harvest problems the following spring when the small grain is mature. This 4-page publication discusses crop competition, knowing your weeds, and chemical control. Written by J. A. Ferrell, G. E. MacDonald, and P. Devkota, and published by the UF/IFAS Agronomy Department, revised May 2020.

Download Full-text

The Affiliative Role of Empathy in Everyday Interpersonal Interactions

10.31234/osf.io/whc43 ◽

2019 ◽

Author(s):

Whitney R. Ringwald ◽

Aidan G.C. Wright

Keyword(s):

Individual Differences ◽

Structural Equation ◽

Community Sample ◽

Empirical Support ◽

Interpersonal Behavior ◽

Equation Modeling ◽

Experimental Conditions ◽

Student Sample ◽

Ecological Momentary

Empathy theoretically serves an affiliative interpersonal function by satisfying motives for intimacy and union with others. Accordingly, empathy is expected to vary depending on the situation. Inconsistent empirical support for empathy’s affiliative role may be due to methodology focused on individual differences in empathy or differences between controlled experimental conditions, which fail to capture its dynamic and interpersonal nature. To address these shortcomings, we used ecological momentary assessment to establish typical patterns of empathy across everyday interactions. Associations among empathy, affect, and interpersonal behavior of self and interaction partner were examined in a student sample (N=330), then replicated in a pre-registered community sample (N=279). Multi-level structural equation modeling was used to distinguish individual differences in empathy from interaction-level effects. Results show people are more empathetic during positively-valanced interactions with others perceived as warm and when expressing warmth. By confirming the typically affiliative role of empathy, existing research to the contrary can be best understood as exceptions to the norm.

Download Full-text

The Pitfalls of Relating Weeds, Herbicide Use, and Crop Yield: Don't Fall Into the Trap! A Critical Review

Frontiers in Agronomy ◽

10.3389/fagro.2020.615470 ◽

2020 ◽

Vol 2 ◽

Author(s):

Nathalie Colbach ◽

Sandrine Petit ◽

Bruno Chauvel ◽

Violaine Deytieux ◽

Martin Lechenet ◽

...

Keyword(s):

Crop Yield ◽

Weed Management ◽

Crop Production ◽

Yield Loss ◽

Crop Yields ◽

Cropping Systems ◽

Crop Productivity ◽

Arable Farming ◽

Herbicide Use ◽

The Impact

The growing recognition of the environmental and health issues associated to pesticide use requires to investigate how to manage weeds with less or no herbicides in arable farming while maintaining crop productivity. The questions of weed harmfulness, herbicide efficacy, the effects of herbicide use on crop yields, and the effect of reducing herbicides on crop production have been addressed over the years but results and interpretations often appear contradictory. In this paper, we critically analyze studies that have focused on the herbicide use, weeds and crop yield nexus. We identified many inconsistencies in the published results and demonstrate that these often stem from differences in the methodologies used and in the choice of the conceptual model that links the three items. Our main findings are: (1) although our review confirms that herbicide reduction increases weed infestation if not compensated by other cultural techniques, there are many shortcomings in the different methods used to assess the impact of weeds on crop production; (2) Reducing herbicide use rarely results in increased crop yield loss due to weeds if farmers compensate low herbicide use by other efficient cultural practices; (3) There is a need for comprehensive studies describing the effect of cropping systems on crop production that explicitly include weeds and disentangle the impact of herbicides from the effect of other practices on weeds and on crop production. We propose a framework that presents all the links and feed-backs that must be considered when analyzing the herbicide-weed-crop yield nexus. We then provide a number of methodological recommendations for future studies. We conclude that, since weeds are causing yield loss, reduced herbicide use and maintained crop productivity necessarily requires a redesign of cropping systems. These new systems should include both agronomic and biodiversity-based levers acting in concert to deliver sustainable weed management.

Download Full-text

Can Enhancing Efficiency Promote the Economic Viability of Smallholder Farmers? A Case of Sierra Leone

Sustainability ◽

10.3390/su13084235 ◽

2021 ◽

Vol 13 (8) ◽

pp. 4235

Author(s):

Silvia Saravia-Matus ◽

T. S. Amjath-Babu ◽

Sreejith Aravindakshan ◽

Stefan Sieber ◽

Jimmy A. Saravia ◽

...

Keyword(s):

Sierra Leone ◽

Technical Efficiency ◽

Structural Equation ◽

Crop Production ◽

Structural Equation Models ◽

Smallholder Farmers ◽

Farming Systems ◽

Economic Viability ◽

Necessary Condition ◽

Smallholder Farming

By developing meta-frontier efficiency and structural equation models, the paper examines whether farm economic viability is positively associated with technical efficiency in a highly food insecure context, such as that of rural Sierra Leone. The findings show that technical efficiency can be a sufficient but not necessary condition in determining economic viability of smallholder farming. It is possible to breach reproductive thresholds at the cost of reduced technical efficiency, when the crop diversification strategy of smallholders includes market-oriented high-value crops. This calls for a dual policy approach that addresses farmers’ internal needs for self-consumption (increasing efficiency of food crop production) while encouraging market-oriented cash crop production (diversification assisted through the reduction of associated transaction costs and the establishment of accessible commercialization channels of export related crops and/or high-value crops). The work also calls out for a move-up or move-out strategy for small holders to create viable farming systems in developing world.

Download Full-text

Age-Related Effects on Interoceptive Accuracy, General Interoceptive Sensibility, and Specific Interoceptive Sensibility

European Journal of Health Psychology ◽

10.1027/2512-8442/a000060 ◽

2020 ◽

Vol 27 (4) ◽

pp. 154-170 ◽

Cited By ~ 1

Author(s):

L. Nusser ◽

O. Pollatos ◽

D. Zimprich

Keyword(s):

Structural Equation ◽

Empirical Support ◽

Self Report ◽

Three Dimensions ◽

Equation Modeling ◽

Adult Lifespan ◽

Age Related ◽

Physical Diseases ◽

Interoceptive Accuracy ◽

Subjective Belief

Abstract. Background: The current research into interoception distinguishes between interoceptive accuracy (IAcc), the accurate detection of internal sensations (e.g., heartbeats) as measured by performance on objective IAcc tasks, and interoceptive sensibility (IS), the subjective belief concerning one’s own experience of internal sensations as measured either through self-report questionnaires or through one’s confidence in the accuracy during an IAcc task. Aims: As the two measures of IS, however, are usually uncorrelated and show differential relationships to IAcc, we suggest different types of IS, a general IS and a specific IS. Further, based on a growing body of research linking IAcc and IS to physical and mental diseases, the development of interoception across the adult lifespan is of importance. Methods: Using Structural Equation Modeling the present paper investigates the relationships among IAcc assessed by a heartbeat counting task, and the two proposed dimensions of IS in 138 participants ( Mage = 42.67, SDage = 18.77). Furthermore, we examine age-related differences in IAcc, as well as in general and specific IS. Results: In terms of the relationship between the three dimensions, general and specific IS were weakly correlated and exhibited different relationships to IAcc. Further, we found different age effects on the three interoceptive dimensions. Whereas IAcc decreased with age, specific IS tend to increase with age, and general IS remained unaffected by age. Conclusion: The findings provide further empirical support for a dissociation between general and specific IS and raised important questions concerning the relation between interoceptive accuracy and the emergence of physical diseases in older age.

Download Full-text

The quicker, the better? The antecedents and consequences of response timing strategy in the aftermath of a corporate crisis

Baltic Journal of Management ◽

10.1108/bjm-06-2017-0185 ◽

2019 ◽

Vol 14 (1) ◽

pp. 19-38 ◽

Cited By ~ 1

Author(s):

Nengzhi (Chris) Yao ◽

Jiuchang Wei ◽

Weiwei Zhu ◽

Alexander Bondar

Keyword(s):

Media Coverage ◽

Firm Value ◽

Structural Equation ◽

Empirical Support ◽

Equation Model ◽

Response Strategy ◽

Content Type ◽

Response Timing ◽

Buffering Effects

Purpose The conclusions on the importance of corporate response timing to a crisis have remained inconsistent. Some studies suggest that active response may reduce negative impacts, whereas managers argue that issuing official response frustrates stakeholders and thus decreases the firm value. The purpose of this paper is to investigate the role of external media in the response timing strategy and the consequent stock market reaction. Design/methodology/approach Based on 130 corporate crises that befell publicly listed firms in China from 2007 to 2014, this paper uses the Baidu News Search Engine and Chinese Lexical Analysis System to construct the variables of the media characteristics. A structural equation model is established to test the hypotheses. Findings The results of this paper suggest that media coverage drives response timing after a crisis. Although an official response is a burden for firms, the timing strategy has multidimensional benefits including effectively alleviating negative effects (defined as buffering effects) and repairing the market (defined as restoring effects). Moreover, the buffering effects of response timing are stronger when completeness of response is low. Originality/value This study mainly contributes to crisis communication literature by introducing the role of media in prompting managers to make timing decisions. The findings of this study provide empirical support for the importance of timing response strategy.

Download Full-text

A rotation design to reduce weed density in organic farming

Renewable Agriculture and Food Systems ◽

10.1017/s1742170510000256 ◽

2010 ◽

Vol 25 (3) ◽

pp. 189-195 ◽

Cited By ~ 29

Author(s):

Randy L. Anderson

Keyword(s):

Population Dynamics ◽

Organic Farming ◽

Weed Management ◽

Crop Production ◽

Soil Health ◽

Population Based ◽

Weed Population ◽

Weed Density ◽

Organic Systems ◽

Herbicide Use

AbstractWeeds are a major obstacle to successful crop production in organic farming. Producers may be able to reduce inputs for weed management by designing rotations to disrupt population dynamics of weeds. Population-based management in conventional farming has reduced herbicide use by 50% because weed density declines in cropland across time. In this paper, we suggest a 9-year rotation comprised of perennial forages and annual crops that will disrupt weed population growth and reduce weed density in organic systems. Lower weed density will also improve effectiveness of weed control tactics used for an individual crop. The rotation includes 3-year intervals of no-till, which will improve both weed population management and soil health. Even though this rotation has not been field tested, it provides an example of designing rotations to disrupt population dynamics of weeds. Also, producers may gain additional benefits of higher crop yield and increased nitrogen supply with this rotation design.

Download Full-text

Weeds and their Management under Changing Climate: A Review

Agricultural Reviews ◽

10.18805/ag.r-2054 ◽

2020 ◽

Author(s):

Jeena Mary

Keyword(s):

Climate Change ◽

Weed Management ◽

Integrated Approach ◽

High Plasticity ◽

Potential Yield ◽

Changing Climate ◽

Weed Diversity ◽

Major Factors ◽

Long Term Impact ◽

The Impact

World is now facing a greater menace of climate change and this has a long term impact on agriculture system. Weeds are one of the major factors that hold back the crops from attaining potential yield. The changing climate can have an effect on weed diversity, establishment and management. The response of weeds to altering climate mainly leans on the physiological characteristics of the weed and how productively it can respond to the immediate climatic condition. Due to high plasticity of weeds, management of these unwanted plants become difficult. This has significant repercussions on weed control practices, especially herbicide performance and effectiveness. Therefore, an integrated approach of weed management is adopted to reduce the impact of climate change on crop-weed interaction.

Download Full-text

Relation between Soil Weed Seedbank and Weed Management Practises and Diversity in Farms in Kisii Central Sub County, Nyanza

Journal of Horticulture and Plant Research ◽

10.18052/www.scipress.com/jhpr.10.1 ◽

2020 ◽

Vol 10 ◽

pp. 1-14

Author(s):

Charles N. Nyamwamu ◽

Rebecca Karanja ◽

Peter Mwangi

Keyword(s):

Seed Bank ◽

Weed Management ◽

Management Practices ◽

Soil Seed Bank ◽

Shannon Index ◽

Weed Seed ◽

Weed Species ◽

Western Kenya ◽

Weed Diversity ◽

Hand Weeding

This study sought to determine the relation between soil weed seed bank and weed management practices and diversity in farms in Kisii Central Sub County, Western Kenya. Eight administrative sub-locations were randomly selected. Ten farms were selected at equal distance along transect laid across each sub-location. Weed soil seed bank was assessed from soil samples collected from each of the farms; a sub-sample was taken from a composite sample of ten soil cores of 5cm diameter and 15cm deep and placed in germination trays in a greenhouse. Weed diversity in soil weed seedbank was calculated using the Shannon index (H’). Twelve weed species from 12 genera of nine families were recorded. Diversity of the weed species in soil weed seed bank was (H'=1.48). Weed management practises significantly affected weed species soil weed seedbank reserves. Use of inefficient and ineffective hand-weeding techniques resulted in high weed species diversity and abundance.

Download Full-text