Competitive Ability Research Articles

Is competitive ability the key adaptation to benign environments? Revisiting experiments on closely related species of tidal plants.

A central goal in biology is to understand which traits underlie adaptation to different environments. Yet, few studies have examined the relative contribution of competitive ability towards adaptive divergence among species occupying distinct environments. Here, we test the relative importance of competitive ability as an adaptation to relatively benign versus challenging environments, using previously published studies of closely related species pairs of primarily tidal plants subjected to reciprocal removal with transplant experiments in nature. Subordinate species typically occupy more challenging environments and showed consistent evidence for adaptation to challenging conditions, with no significant competitive effect on non-local, dominant species. In contrast, dominant species typically occupy relatively benign environments and performed significantly better than non-local, subordinate species that faced competition from the dominant species. Surprisingly, when the two species were not allowed to compete, the subordinate species performed as well as the dominant species in the benign environments where the subordinate species do not occur. These results suggest that competitive ability is the most important adaptation distinguishing the species that occupy relatively benign environments. The limited scope and number of suitable experimental studies encourage future work to test if these results are generalizable across taxa and environments.

Can competitive effects and responses of alien and native species predict invasion outcomes?

The relative competitive ability of native and alien species, which consists of competitive effect (CE) and response (CR), has often been invoked as a key determinant of invasion success. Previous studies have reported that an alien species with a high CE and/or a low CR would successfully invade a native species. However, no studies have yet empirically examined the hypothesis or tested the consistency of invasion outcomes predicted by the CE-CR framework and modern species coexistence theory (MCT). To fill this research gap, we conducted a pairwise competition experiment between five alien and five native species, quantified CE and CR based on their biomass in the absence and presence of one competitor, and predicted invasion outcomes based on both CE-CR and MCT frameworks. We have demonstrated theoretically that the CE and CR frequently measured in previous work are only approximations of interspecific competitive coefficients, and thus could not completely predict the invasion outcomes. As we expected, the invasion outcomes predicted by the CE-CR framework were partially consistent with the predictions by the MCT framework. Specifically, aliens with low CR and high CE tended to exclude natives, while aliens with high CR and low CE tended to be excluded by natives according to MCT. In contrast, pairs of stable coexistence and priority effects did not conform to the theoretical expectation. Despite the theoretical defects of the CE-CR framework, it can provide some useful value in predicting the invasion outcomes, especially when intrinsic growth rate and intraspecific competition coefficients are not available. Our study is the first to compare invasion outcomes separately derived from qualitative (the CE-CR framework) and quantitative (the MCT framework) methods. We recommend that future research should adopt quantitative approaches such as MCT as far as possible, to more comprehensively understand and predict the biotic outcomes of interacting species.

Morpho-physiological responses of potato cultivars under weed competition

Morpho-physiological responses of potato cultivars under weed competition

“一带一路”沿线国家来华留学生就业创业研究综述

With the in-depth progress of the “Belt and Road” construction, China has closer relations with the countries along the “Belt and Road”. Cultural and people-to-people exchanges and educational cooperation are among the top priorities. In the context of the opening up of education in the new era, Chinese government established the “four beams and eight pillars” educational frame to attract a large number of international students to study in China. Meanwhile, it puts forward new requirements for colleges and universities to improve the quality of education and training for international students, in which include the cultivation of international students' employment competitiveness and entrepreneurship ability. This paper summarizes the theoretical research on the employment and entrepreneurship of international students at home and abroad, and reviews status of empirical research on employment and entrepreneurship of international students in countries along the Belt and Road. Then based on the discussion, it proposes the direction of future research.

HR INNOVATION IN MEDIATING ENTREPRENEURIAL MOTIVATION IN IMPROVING THE COMPETITIVE ABILITY OF PALU FRIED ONIONS MSMES

Purpose – This study aims to describe the competitive ability of MSMEs Palu Fried Onions (BGP) from the point of view of human resources, namely innovation and the influence of motivation. Research methodology – This research was conducted on 141 active BGP MSMEs in Palu and tested using quantitative methods using SEM-PLS analysis testing. Findings – The study results show that Human Resource Innovation is proven to affect the ability of the Palu Fried Onions MSMEs. Research limitations – A limitation of this study is that it focuses solely on the competitive abilities of BGP MSMEs from the perspective of human resources, specifically innovation and motivation, and does not explore other potential factors that might influence their competitiveness. Practical implications – The results of this study have the benefit of being practical considerations for driving BGP MSMEs to increase their competitiveness; besides that, the results of this study also expand the variation of the Diamond Model or the Diamond Model of production factors to be competitive. Originality/Value – Rather than focusing solely on traditional factors, this research delves into the innovative realm of human resource innovation and motivation as key drivers of competitiveness.

Новое издание учебника «Конкуренция в предпринимательстве» для вузов

A review for the new edition of the textbook “Competition in Entrepreneurship” for higher educational institutions, published by the University publishing house “Synergy”, is presented. The following main advantages of the textbook are noted: the presence of the author’s view on such issues as the process of competitiveness, its objects, subjects, actors, results, resources, types and character of competitive interaction, types of competitive actions, methods of operational interaction between competitive parties, competitive stability and competitive ability, competitive positions, competitive status, competitive strategies, tactical competitive operations and combinations, competitive situations, competitive tricks and puzzles, management of competitive actions, competitive analysis. In the context of digital economy and the application of intelligent management technologies, the use of the considered publication in the educational process will allow university students to develop the knowledge and skills necessary to conduct successful business activities in modern economic conditions. The tools described in the textbook can be effectively used at the strategic, operational and situational levels of participation in competition, considering the potential for its implementation as part of the organization corporate information systems.

Temperature dependence and genetic variation in resource acquisition strategies in a model freshwater plant

Abstract Understanding how competition varies with environmental stress is critical to anticipating species and community responses to rapid environmental change. While the stress‐gradient hypothesis predicts the strength of competition to decrease with increasing stress, our understanding of how competition varies with stress is limited by a lack of mechanistic understanding of how resource‐use traits underlying competitive dynamics respond to stress. Here, we use duckweeds in the Lemna species complex to measure how phenotypic and genetic variation in R* (a resource acquisition trait representing the minimum resource requirement for positive population growth) varies with high‐temperature stress to better understand how stress alters competitive ability for essential resources. We found that heat stress increased the R* of Lemna plants for nitrogen acquisition. Because lower R* values predict dominance in competitive dynamics where resources are limiting, this indicates that under stressful, high temperatures, plants could experience reduced competitive ability due to the higher resources required to sustain positive population growth rates. We found minimal genetic variation in R* across 11 local genotypes within the Lemna species complex, indicating that selection on resource acquisition strategies for essential resources such as nitrogen may be constrained in nature. The expression of genetic variation in R* for nitrogen was further reduced under heat stress, suggesting that the response to selection for R* could be particularly constrained under high‐temperature stress. Contrary to predictions drawn from the gleaner–opportunist trade‐off, we did not find evidence for a trade‐off in resource acquisition strategies under benign conditions or high‐temperature stress. Plants with lower R* (i.e. higher growth rates under lower nitrogen levels) were not constrained to have lower growth rates under higher nitrogen levels, possibly because the chosen genotypes have not diverged across resource acquisition strategies or because Lemna spp. has escaped this constraint. Importantly, our work indicates that high‐temperature stress could increase sensitivity to competition through an increased requirement for resources while reducing the evolutionary potential for Lemna species to respond to selection for resource traits. This study acts as a key step to understanding the mechanistic traits behind competitive dynamics in resource‐limited and stressful environments. Read the free Plain Language Summary for this article on the Journal blog.

“Research on the construction of internet based aerobics competitive ability assessment model”

A vast field that focuses on restoring motor abilities through exercise is known as sports rehabilitation training, which is also sometimes referred to as recovery athletic exercise. A background in sporting recovery can assist competitors in getting back into peak physical condition, recovering from injuries, preventing additional damage, and better coping with the demands of regular practice. The importance of sports rehabilitation teaching for physical activity is analyzed and discussed at length throughout this research. The definition of sports therapy is presented first, followed by an examination of how it might be used to fitness. Make use of this information as a reference to discover how to include physical therapy in the workout plan you use for sports conditioning. Many tried-and-true algorithms for monitoring patients' vitals over time have emerged as a result of widespread use and advancements in IHM technology, which has led to an increase in the number of such algorithms. The purpose of this research is to investigate the ways in which intelligent health monitoring systems can be applied to the process of developing rehab methods for athletes. It not only provides the structure for a smart wellness terminal, but it also offers the usual ways for monitoring a moving object. Methods such as this include the optical flow strategy, the frame contrast technique, and the background difference method, to name just a few examples. The process of rehabilitation that an athlete went through in X city is presented as an example to show the processes that are included in an ideal study. According to the findings of the study, 92.6 percent of the athletes with injuries were able to make a full recovery with the support of rehabilitative physical exercise. The researchers were able to determine this by keeping close track on the athletes' vital signs in real time using sophisticated health monitoring equipment.

Simultaneous size and defect control of metal-organic framework by deep eutectic solvent for efficient perfluoroalkyl substances adsorption: Delving into mechanism

This study reports an environment-friendly protocol to prepare a metal–organic framework (MOF) with simultaneously controlled particle size and open metal site for adsorption removal of perfluoroalkyl substances (PFASs). The successful preparation of UiO-66 with defect and crystal size modulation was achieved using a green and straightforward method, adjusting the components and molar ratios of ammonium salt/glycolic acid deep eutectic solvents (DESs). The corresponding modulation mechanism primarily relied on the combined regulation of the deprotonation and competitive coordination abilities of the eutectic solvent components. The adsorption process was thoroughly examined using spectral analyses, adsorption behavior profiling, and ab initio molecular dynamics simulations. The results revealed that PFAS adsorption is driven by combined capturing effects, such as CF–π, acid/base coordination, C–F⋯Zr, hydrogen bonding, and hydrophobic interactions. Our findings were not thus that the smaller the crystal size of MOF and the higher the defect concentration in the material, the better the PFAS adsorption performance. The result demonstrated the combined effect of these adsorbent features on PFAS mixtures. Furthermore, they revealed unique differences in sorption properties between these targets with different carbon chain lengths. Extensive defects in DES-based UiO-66 led to larger pores, increasing the availability of many adsorption sites and aiding in PFAS adsorption and diffusion. Nevertheless, the surplus of larger pores in the substance increased the competitive adsorption, reducing the total quantity of PFASs absorbed. Furthermore, various interactions and a less restrictive configuration increased the contact of functional groups with adsorbates, substantially enhancing the adsorption. This study investigates the basic questions about how PFAS molecules are adsorbed on DES-based MOFs and the relationship among the structure, properties, and performance to improve the efficiency of this novel adsorbent.

IMPACT OF SOIL STERILIZATION FROM DIFFERENT LOCATIONS, WHEAT SEEDS CLEANING AND THEIR INTERACTIONS ON WEED CONTROL, AND YIELD AND YIELD COMPONENTS

IMPACT OF SOIL STERILIZATION FROM DIFFERENT LOCATIONS, WHEAT SEEDS CLEANING AND THEIR INTERACTIONS ON WEED CONTROL, AND YIELD AND YIELD COMPONENTS

Morphophysiological responses of conventional and gm soybean with distinct biotechnological background to weed competition

New technologies developed to control weeds in crops are flourishing in recent years. Therefore, the objective of this work was to study the competitive ability of soybean cultivars C2531E (Enlist®), M6410 IPRO (RR2®) and BRS 257 (conventional), with distinct biotechnological background, when competing against Euphorbia heterophylla and Urochloa plantaginea. Crops and competitors were studied in distinct plant proportions: 24:0; 18:6; 12:12; 6:18 and 0:24 plants per plot. Fifty days after emergence, plant height, leaf area (AL) and aboveground dry mass (DM), photosynthetic and transpiration rates and stomatal conductance were assessed. Crop responses to competition tended to be species-specific. Soybean M6410 IPRO presents better morphophysiological performance compared to C2531E and BRS 257 when it competed against U. plantaginea. The soybean BRS 257 showed greater LA when competing against U. plantaginea. The competitiveness indices showed that M6410 IPRO responses to competition by accumulating aboveground DM while C2531E responsesby increasing LA. There was difference among cultivars in their strategy to deal with the weed competition, and M6410 IPRO had better competitive ability than the other cultivars when it competed against E. heterophylla.

Effect of intestinal nitrate on growth of Klebsiella pneumoniae and its regulatory mechanism

To explore the effect of intestinal nitrates on the growth of Klebsiella pneumoniae and its regulatory mechanisms. K. pneumoniae strains with nitrate reductase narG and narZ single or double gene knockout or with NarXL gene knockout were constructed and observed for both aerobic and anaerobic growth in the presence of KNO3 using an automated bacterial growth analyzer and a spectrophotometer, respectively. The mRNA expressions of narG and narZ in K. pneumoniae in anaerobic cultures in the presence of KNO3 and the effect of the binary regulatory system NarXL on their expresisons were detected using qRT-PCR. Electrophoretic mobility shift assays (EMSA) and MST analysis were performed to explore the specific regulatory mechanisms of NarXL in sensing and utilizing nitrates. Competitive experiments were conducted to examine anaerobic growth advantages of narG and narZ gene knockout strains of K. pneumoniae in the presence of KNO3. The presence of KNO3 in anaerobic conditions, but not in aerobic conditions, promoted bacterial growth more effectively in the wild-type K. pneumoniae strain than in the narXL gene knockout strain. In anaerobic conditions, the narXL gene knockout strain showed significantly lowered mRNA expressions of narG and narZ (P < 0.0001). EMSA and MST experiments demonstrated that the NarXL regulator could directly bind to narG and narZ promoter regions. The wild-type K. pneumoniae strain in anaerobic cultures showed significantly increased expressions of narG and narZ mRNAs in the presence of KNO3 (P < 0.01), and narG gene knockout resulted in significantly attenuated anaerobic growth and competitive growth abilities of K. pneumoniae in the presence of KNO3 (P < 0.01). The binary regulatory system NarXL of K. pneumoniae can sense changes in intestinal nitrate concentration and directly regulate the expression of nitrate reductase genes narG and narZ to promote bacterial growth.

Evaluation of shoot-growth variation in diverse carrot (Daucus carota L.) germplasm for genetic improvement of stand establishment.

Carrot (Daucus carota L.) is a high value, nutritious, and colorful crop, but delivering carrots from seed to table can be a struggle for carrot growers. Weed competitive ability is a critical trait for crop success that carrot and its apiaceous relatives often lack owing to their characteristic slow shoot growth and erratic seedling emergence, even among genetically uniform lines. This study is the first field-based, multi-year experiment to evaluate shoot-growth trait variation over a 100-day growing season in a carrot diversity panel (N=695) that includes genetically diverse carrot accessions from the United States Department of Agriculture National Plant Germplasm System. We report phenotypic variability for shoot-growth characteristics, the first broad-sense heritability estimates for seedling emergence (0.68 < H2 < 0.80) and early-season canopy coverage ( 0.61 < H2 < 0.65), and consistent broad-sense heritability for late-season canopy height (0.76 < H2 < 0.82), indicating quantitative inheritance and potential for improvement through plant breeding. Strong correlation between emergence and canopy coverage (0.62 < r < 0.72) suggests that improvement of seedling emergence has great potential to increase yield and weed competitive ability. Accessions with high emergence and vigorous canopy growth are of immediate use to breeders targeting stand establishment, weed-tolerance, or weed-suppressant carrots, which is of particular advantage to the organic carrot production sector, reducing the costs and labor associated with herbicide application and weeding. We developed a standardized vocabulary and protocol to describe shoot-growth and facilitate collaboration and communication across carrot research groups. Our study facilitates identification and utilization of carrot genetic resources, conservation of agrobiodiversity, and development of breeding stocks for weed-competitive ability, with the long-term goal of delivering improved carrot cultivars to breeders, growers, and consumers. Accession selection can be further optimized for efficient breeding by combining shoot growth data with phenological data in this study's companion paper to identify ideotypes based on global market needs.

Changes in concentration performance and alternating attention after short-term virtual reality training in E-athletes: a pilot study

In the dynamic landscape of e-sports, where intense competitive gaming demands high cognitive abilities, concentration performance and alternating attention play a pivotal role. E-sports encompass diverse genres, each requiring specific cognitive functions. Maintaining unwavering focus is crucial, as split-second decisions can determine victory. The study explores the potential of Virtual Reality (VR) training to enhance concentration performance and alternating attention, shedding light on the importance and possibilities of optimizing cognitive abilities for e-athletes. VR training emerges as a promising intervention, offering immersive environments for cognitive exercises. The study investigates the impact of VR training on concentration performance and alternating attention in amateur e-athletes, utilizing standardized tests. A randomized controlled trial with 66 participants reveals significant improvements in the VR training group, highlighting the adaptability and plasticity of cognitive processes. The findings suggest that VR training can enhance concentration abilities, providing valuable insights for e-sports and potentially extending to other fields requiring sustained attention and rapid task-switching. The study underscores the convergence of cognitive psychology, neuroscience, and VR technology, paving the way for innovative training methodologies and advancements in e-sports performance.

Introgression of early shoot vigour in wheat modifies root systems, increases competitiveness and provides options for integrated weed management

Abstract Background and aims Weeds are a major biotic stressor impacting crop production. Improving the competitiveness of wheat (Triticum aestivum L.) could provide a useful tool in integrated weed management. While wheat typically exhibits conservative early growth, early vigour has been increased through long-term recurrent selection for greater early biomass and leaf area. However, the influence of integrating such vigour into breeding lines for improving competitive ability remains to be explored. Methods In replicated controlled environment experiments, the effect of breeding early shoot vigour on root development and below-ground competitiveness was carefully examined. Physical and chemical characteristics of wheat vigour lines were assessed and compared with commercial cultivars in hydroponics and field soil experiments. Measurements included early root growth, rhizosheath size and growth responses in the presence of annual ryegrass, a major weed in wheat production. Results The vigorous lines exhibited larger leaf widths, increased cell file number, increased total root length and larger rhizosheaths compared with commercial parents. Numerous secondary metabolites with known allelopathic effects on weeds were detected in the roots and the rhizosphere, and significant allelochemical level differences observed between distilled water and soil water extract-treated plants. Although the vigour lines were significantly more competitive than the commercial cultivars against ryegrass, they produced similar levels of phytotoxic secondary metabolites. Conclusion Competition below-ground was strongly suppressive of ryegrass for the more vigorous genotypes suggesting that breeding with shoot vigour had pleiotropic effects on key root traits for below-ground wheat competitiveness.

The Effects of Infectious Diseases on the Consequences of Interspecific Competition in Grassland Communities

As infectious diseases have a severe impact on the individual survival and competitive ability of host species in grassland communities, competition between relevant species may have different consequences, potentially influencing the species composition of grassland communities and the functioning of grassland ecosystems. Understanding the impact of infectious diseases on competition is thus crucial for the health management of grassland ecosystems. How do infectious diseases affect the competitive coexistence of grassland plant species? In this study, by drawing on Tilman’s multispecies competition model and incorporating the spread characteristics of grassland plant diseases, we built three spatial competition models of two grass species subject to infectious diseases, and we analyzed the invasion conditions of infectious diseases and how they impact the population dynamics and competitive consequences of the species. Our model revealed the following: (1) Diseases with high transmission rates and low virulence are more likely to invade populations, while the presence of non-host species is detrimental to disease invasion. (2) Disease promotes the coexistence of competing species, breaking down the original competition–compromise trade-off mechanism for species coexistence and greatly expanding the range of parameters within which the two species can coexist. (3) Pathogen infections indirectly weaken the suppression of inferior species by dominant species, which is similar to the cascade effect seen in trophic interactions. Our findings highlight the importance of disease in species coexistence and grassland biodiversity maintenance.

When simplicity triumphs: niche specialization of gut bacteria exists even for simple fiber structures.

Structurally complex corn bran arabinoxylan (CAX) was used as a model glycan to investigate gut bacteria growth and competition on different AX-based fine structures. Nine hydrolyzate segments of the CAX polymer varying in chemical structure (sugars and linkages), CAX, five less complex non-corn arabinoxylans, and xylose and glucose were ranked from structurally complex to simple. The substrate panel promoted different overall growth and rates of growth of eight Bacteroides xylan-degrading strains. For example, Bacteroides cellulosilyticus DSM 14838 (Bacteroides cellulosilyticus) grew well on an array of complex and simple structures, while Bacteroides ovatus 3-1-23 grew well only on the simple structures. In a competition experiment, B. cellulosilyticus growth was favored over B. ovatus on the complex AX-based structure. On the other hand, on the simple structure, B. ovatus strongly outcompeted B. cellulosilyticus, which was eliminated from the competitive environment by Day 11. This adaptation to fine structure and resulting competition dynamics indicate that dietary fiber chemical structures, whether complex or simple, favor certain gut bacteria. Overall, this work supports a concept that fiber degraders diversify their competitive abilities to access substrates across the spectrum of heterogeneity of fine structural features of dietary fibers.

A study on the impact of systematic desensitization training on competitive anxiety among Latin dance athletes.

In the domain of competitive events, Latin dance athletes have always suffered competitive anxiety, which is a prevalent and prevailing psychological facet, in pre-, intra-, and post-competitive engagements. Usually, the implementation of systematic desensitization training is an efficacious approach to reduce competitive anxiety levels in routine sports to fortify psychological resilience of athletes (like swimming, volleyball, and basketball). This study focuses on the effect of systematic desensitization training on competition anxiety in the training of Latin dancers to establish good mental ability and promote the competitive ability of athletes. The "Sports Competition Anxiety Test Questionnaire" was used to evaluate and classify the competitive anxiety levels of 150 Latin dance athletes. Then, the top 48 participants were selected (24 in the intervention cohort and 24 in the non-intervention cohort) as the study participants after stratifying anxiety score levels from the highest to the lowest. The intervention group was treated with an 8-week psychological intervention by employing systematic desensitization training techniques (encompassing imagery desensitization and in vivo desensitization). The anxiety levels of the subjects were quantified by employing the "Sport Competition Trait Anxiety Inventory" (CCTAI-C) and the "Competitive State Anxiety Inventory" (CSAI-2) to scrutinize the efficacy of systematic desensitization training in regulating competitive anxiety levels among Latin dance athletes. After applying systematic desensitization training, the intervention group displayed a notable reduction in sport cognitive trait anxiety. Specifically, there was a decrease of 29.37% in social evaluation anxiety, 20.31% in competition preparation anxiety, 16.98% in performance anxiety, 25.16% in failure anxiety, 34.47% in opponent's ability anxiety, and 25.16% in injury anxiety. Moreover, for competitive state anxiety, cognitive state anxiety and somatic state anxiety decreased by 39.19 and 21.43%. The state self-confidence increased by 14.42%. The result indicated that systematic desensitization training not only mitigates anxiety but also positively intervenes in sports-related anxiety. Moreover, systematic desensitization training can significantly diminish competitive anxiety among Latin dance athletes to bolster confidence during competitions. Integrating desensitization training into the regular regimen of Latin dance practice has the potential to fortify dancers' psychological resilience against anxiety.

Intraspecific variation in fine-root traits is larger than in aboveground traits in European herbaceous species regardless of drought.

Differences within species (Intraspecific trait variation - ITV) contribute substantially to overall trait variability and environmental harshness can reduce among-species variation. While aboveground traits have received considerable attention, knowledge about ITV in fine-root traits and how it differs from ITV in aboveground traits remains limited. This study examined the partitioning of trait variation aboveground and fine-root traits in 52 European herbaceous species and how such proportions change in response to drought, offering valuable insights for accurate functional species characterization and inter-species comparisons. We studied seven morphological aboveground and fine-root traits under drought and well-watered conditions in a greenhouse experiment. Linear mixed effect models and permutational multivariate analysis of variance (PERMANOVA) were employed to decompose trait variation, ensuring the robustness of our results. We also calculated variance partitioning for the combination of aboveground traits and the combination of fine-root traits, as well as pairs of analogous leaf and fine-root traits (i.e., traits that fulfill similar functions) for each treatment (control and drought). Among-species trait differences explained a greater proportion of overall variance than within-species variation, except for root dry matter content (RDMC). Height and leaf area stood out, with species' identity accounting for 87-90% of total trait variation. Drought had no significant effect on the proportions of variation in any of the traits. However, the combination of fine-root traits exhibited higher intraspecific variability (44-44%) than aboveground traits (19-21%) under both drought and control. Analogous root traits also showed higher ITV (51-50%) than analogous leaf traits (27-31%). Our findings highlight substantial within-species variation and the nuanced responses of fine-root traits, particularly RDMC, suggesting root traits' flexibility to soil heterogeneity that fosters less differentiation among species. Among-species trait differences, especially aboveground, may underscore distinct strategies and competitive abilities for resource acquisition and utilization. This study contributes to elucidate the mechanisms underlying the multifunctionality of the above- and belowground plants compartments.

Utilization of the Neighborhood Design to Evaluate Suitable Pasture Crops and Their Density for Navua Sedge (Cyperus aromaticus) Management

Navua sedge (Cyperus aromaticus), a perennial plant native to Africa, poses a significant weed concern due to its capacity for seed and rhizome fragment dissemination. Infestations can diminish pasture carrying capacity, displacing desirable species. Despite the burgeoning interest in integrated weed management strategies, information regarding the efficacy of competitive interactions with other pasture species for Navua sedge management remains limited. A pot trial investigated the competitive abilities of 14 diverse broadleaf and grass pasture species. The results indicated a range of the reduction in Navua sedge dry biomass from 6% to 98% across these species. Subsequently, three broadleaf species—burgundy bean (Macroptilium bracteatum), cowpea (Vigna unguiculata), and lablab (Lablab purpureus), and three grass species—Gatton panic (Megathyrsus maximus), Rhodes grass (Chloris gayana), and signal grass (Urochloa decumbens) were chosen for a follow-up pot trial based on their superior dry biomass performance. These six species were planted at three varying densities (44, 88, and 176 plants/m2) surrounding a Navua sedge plant. Among the grass pasture species, Gatton panic and Rhodes grass exhibited high competitiveness, resulting in a minimum decrease of 86% and 99%, respectively, in Navua sedge dry biomass. Regarding the broadleaf species, lablab displayed the highest competitiveness, causing a minimum decrease of 99% in Navua sedge dry biomass. This study highlights the increasing efficacy of crop competition in suppressing weed growth and seed production, with the most significant suppression observed at a density of 176 plants/m2.