Weed Abundance Research Articles

Benefit of weeds for crop-plant mycobiota in agroecosystems: Integrating ecological demonstration and management applicability

Agricultural intensification reduces not only biodiversity in agroecosystems but also key ecosystem functions such as soil fertility. By reintroducing biological diversity in fields, weeds may enhance soil biological fertility through their influence on crop microbiota. However, letting weeds grow in crop fields will depend on weed competitiveness, farmers’ perception and acceptance, and on crop management, which influences the occurrence and the abundance of weeds in the field. This study assessed the use of eight weed species to modify wheat plant root endospheric mycobiota, and the applicability of using these plants for mycobiota enrichment in the field. By combining controlled lab experiments and field studies, we demonstrated that weeds act either as a refuge for a high diversity of fungi or as a vector for transferring fungi to the crop, particularly symbionts. Weeds differed in their competitive effect on wheat growth and only three species significantly reduced wheat growth. Interviews with farmers’ revealed that weed species were better known and more appreciated in crop fields by organic farmers than by conventional farmers. Floristic surveys confirmed that both weed occurrence and cover were higher in organic fields than in conventional fields. A multicriteria analysis showed that Trifolium repens and V. persica had the highest potential for promoting wheat plant mycobiota. Among the weed species tested, these two are worth considering as auxiliaries to improve soil biological fertility in crop fields. Their use with the goal of selecting appropriate crop mycobiota should be relatively easier in organic farms where weeds are better accepted, whereas their use in conventional farms would require raising farmers’ awareness of the benefits of weeds for soil fertility.

Effects of Metribuzin on Soil Microbiome and Weed Management Under Varying Planting Practices and Potato Seed Dormancy

AbstractWeed infestation in potato field has become a major concern to smallholder farmers and environment, requiring sustainable intervention. This study aimed to determine (i) whether metribuzin application rate (0, 0.5, 1 (standard), 1.5, and 2 kg ai ha−1) has effects on soil microbes and soil nutrients in the short term using potted soil and (ii) the influence of potato seed dormancy (short; Shangi variety and long; Unica variety) and planting technique (surface, ridge, or furrow planting) on the efficacy of weed management practice (metribuzin (480 g L−1) herbicide and hoeing) in the field. Bacterial colony counts were recorded upon isolation from the potted soil. Soil nutrients were also analysed before and after metribuzin treatment. Data on crop growth (height and stem count), weed abundance, yield, costs, and revenues were recorded from a field experiment. Morphologically distinct bacterial strains were tested for Gram reaction and response to carbon utilization using analytical profile index kits (API 50 CH and 20 NE). In total, nine distinct bacterial strains were isolated and all were Gram positive, with variation in response to carbon substrates. Concentration of 2.0 kg a.i ha−1 significantly (p ≤ 0.05) reduced bacterial count in the first day, followed by an increase in the subsequent incubation days, while 1.0 and 1.5 kg a.i ha−1 concentrations had the highest colony development index and species richness. Significant effects of metribuzin on soil pH, total N, and total organic C in the short term were revealed. Notably, weedy plots had the highest Shannon weed index. Weeds reduced stem count and height growth by 57% and 62% respectively. Plots with Shangi had 9.8% lower weed count than those with Unica and hence higher yield was recorded from the former. While surface planting had the lowest weed control efficacy, crop growth attributes, and yield, furrow and ridge planting were not significantly different. Weed abundance and crop growth attributes in metribuzin and hand-hoed plots did not differ significantly, yet hoeing resulted in 5.30 t ha−1 above that obtained from plots managed using metribuzin. Higher dry matter and tuber yield were observed from hoed plots with Shangi planted in furrow or ridge. Use of metribuzin resulted in higher net benefit ratio and marginal rate of return than hand hoeing. The results reveal that use of metribuzin early and later in the potato growing phase can minimize weed infestation, but the efficacy depends on planting method and seed dormancy.

From unwanted to wanted: Blending functional weed traits into weed distribution maps

AbstractSite‐specific weed management (SSWM) is increasingly employed to reduce herbicide inputs. Incorporating functional traits of weed species allows for the selection of SSWM methods that effectively reduce the abundance of weeds with a high competitive potential (disservice) while preserving weeds that provide beneficial ecosystem services (service). In this study, we aim to assess relevant weed functional traits and translate this information into a spatial trait distribution map for weed (dis‐)service provision. The distribution of weed abundance in a field was recorded using a spatial grid. Data on functional traits for the recorded weed species were extracted from published datasets and combined into the two variables, service and disservice. Individual traits (service/disservice) were weighted for each pixel of the weed distribution map based on the number of individual plants per species. Principal component analysis was employed to generate independent variables to describe the potential for service and disservice provision. As a result, two (dis‐)service trait‐based distribution maps were generated: one highlights field areas that provide enhanced ecological services, while the other displays areas with a high disservice potential. The results show that around 61% of the area in the field had a high service potential. The area with a high disservice was slightly higher than the half of the area with a high service, while about 32% of the field has both high service and disservice potential in the same area. This study presents a spatially explicit approach to incorporate information on weed functional traits into SSWM approaches targeted at reducing weed competition while at the same time enhancing weed functional diversity.

Fertility and tillage intensity affect weed community diversity and functional structure in long-term organic systems.

Knowledge of how agricultural management interacts with weed seed banks and emergent weed communities is crucial for proactive weed management. Though studies have detailed how differences in disturbance and nutrient applications between organic and conventional herbicide-based systems affect weed communities, few have focused on these same factors in contrasting organic systems. This study assessed the seed banks and emergent weed communities from the most recent crop rotation cycle (2017-2022) of a long-term experiment, which compared four organic grain and forage cropping systems differing in nutrient inputs and soil disturbance. The high fertility (HF) system received high-rate nutrient applications, low fertility (LF) received low-rate applications, enhanced weed management (EWM) focused on weed control through frequent soil disturbance, and reduced tillage (RT) prioritized soil health with less intense or frequent soil disturbance. Soil samples for greenhouse germination assays were collected at the beginning (2017) and end (2022) of the rotation to explore how these four systems influenced seed bank dynamics over time. Weed community biomass was also sampled in each crop during this time. Treatment effects on weed abundance, taxonomic diversity, and community-weighted means and functional dispersion of weed traits were analyzed with generalized mixed-effect models. The RT system had the highest weed seed bank taxonomic diversity, and EWM had the lowest. RT and LF had higher functional dispersion of traits than HF in the seed bank. Weed seed bank communities in HF and RT were characterized by short, small-seeded, and early germinating weed species. However, seed banks were also labile: Differences between systems in seed density and all other mean trait values were dependent on the crop, which preceded seed bank sampling. Likewise, differences among emergent weed communities in the four systems depended on an interaction between crop species and their planting year. Results suggest that resource availability and intensity of disturbance act as weed community assembly filters in organic cropping systems. Organic growers seeking to design systems that balance weed management and production goals can use relatively low soil disturbance and nutrient application to increase weed community taxonomic or functional diversity without necessarily increasing weed biomass or seed bank density.

ECOLOGICAL ATTRIBUTES OF WEEDS AS INDICATORS OF SUSTAINABILITY IN AGROECOSYSTEMS OF THE SOUTHEASTERN REGION OF MEXICO CITY

<p><strong>Background:</strong> Pre-Hispanic agroecosystems in Mexico City have changed the kind of crops, management practices, tools, and inputs, seriously impacting their biocultural value and sustainability. Previous studies have demonstrated these changes' economic, cultural, and political consequences. However, their effects on biodiversity have not been considered. The present study characterized the management carried out in three agroecosystems in the southeastern area of Mexico City and its possible relationship with agrobiodiversity. <strong>Objective</strong>: To evaluate the contribution of diversity, abundance, and composition of weeds as components of the sustainability of agroecosystems in Milpa Alta, Tláhuac, and Xochimilco municipalities. <strong>Methodology: </strong>179 interviews were conducted with campesinos. Weeds sampling in 30 plots, recording the abundance and frequency of each species. These data were used to estimate different ecological parameters. Information on management practices was transformed to develop an “agroecosystem sustainability index.” A multivariate analysis was applied to compare weed attributes between agroecosystems and spaces and to detect possible relationships between the index and ecological parameters. <strong>Results:</strong> 156 species were recorded. The <em>slope</em> had the highest diversity, and <em>ciénega</em> had the lowest. More than half of the weeds were native, and the <em>slope</em> exhibited the highest number. The Importance Value indicated no dominant species on the <em>slope, </em>opposite to<em> chinampa and ciénega</em>. Species composition also differed between the three agroecosystems. <em>Chinampa</em> was impacted the most, whereas the <em>slope</em> was least affected. <strong>Implications:</strong> The displacement of traditional crops and agricultural practices and the incorporation of technological practices have modified the ecological attributes of weeds, like their abundance and composition. <strong>Conclusion:</strong> Starting from the argument that ecological attributes of weeds can be used as an indicator of sustainability, the <em>slope</em> resulted in the agroecosystem being most sustainable and should be used as a model to recover the agrobiodiversity of <em>ciénegas</em> and <em>chinampas</em>. </p>

Sunflower Broomrape (Orobanche cumana Wallr.) and Weeds in Sunflower Crops with Minimized Tillage in a Steppe Ecotype Crop Rotation

Abstract An important reserve for increasing the productivity of agricultural production is a scientifically based crop structure and the use of rational crop rotations, which implement the optimal ratio of agroecological standards. The aim of the research was to determine the influence of elements of agrotechnical measures, in particular, the saturation of crop rotations with sunflower, soil tillage system on the number and species composition of various agrobiological groups of weeds in sunflower crops, including the weed parasite sunflower broomrape (Orobanche cumana Wallr.). Weed control measures and the spread of the parasitic weed sunflower broomrape in sunflower crops have been carried out according to the methods generally accepted in agriculture and weed science. The scheme of the experiment included crop rotations with saturation in the structure of sunflower sowing of 12.5, 20, 25, 33.3, 50, 100% and three systems of basic tillage: moldboard plowing, disc tillage, and no-tillage. As a result of the research, it has been found that the systems of disc tillage and no-tillage cause an increase in the number of weeds in sunflower crops compared to the moldboard plowing by 1.3–1.5 times. On average, over the years of research, the abundance of weeds in the plots when using disk tools was 10.4–15.1 pcs./m2, moldboard plowing was 7.1–12.4 pcs./m2, and before harvesting was 2.6–5.2 and 4.1–12.4 pcs./m2. The highest degree of sunflower broomrape damage has been observed in 2-fields crop rotation (winter wheat—sunflower) and permanent sunflower cultivation, as 16.0–32.4% of affected sunflower plants have been observed here. The intensity of sunflower broomrape damage to sunflower plants was higher in the moldboard plowing system and amounted to 1.2–8.3 pcs./per plant, which exceeded disc tillage and no-tillage by 1.2–1.6 times. The maximum seed yield of 2.92–2.95 t/ha has been obtained in 8- and 5-fields rotations with the use of moldboard plowing. The lowest yields of sunflower seeds were in short-rotation crop rotations with a sunflower saturation of 50% in the structure of sown areas and permanent cultivation and amounted to: moldboard plowing—1.75–2.21 t/ha, disk tillage—1.57–2.01 t/ha, and no-tillage—1.49–1.95 t/ha. Given the urgency of supplying the global market with sunflower oil, in the future it is necessary to increase the concentration of sunflower in the structure of sown areas to 30-40% through the system of basic tillage, selection of resistant hybrids, and use of herbicides.

Effect of increasing temperature and temperature fluctuations on alfalfa and orchardgrass in the establishment year

AbstractUnderstanding how a warmer and more variable climate will affect the productivity and stability of perennial forages in the establishment year is essential for determining forage management strategies resilient to the changing climate. We conducted an experiment from 2020–2021 and repeated it in 2021–2022 to determine how warmer and more variable temperatures affect yield of an alfalfa (Medicago sativa L.)–orchardgrass (Dactylis glomerata L.) mixture, as well as on the abundance of a winter annual weed, chickweed (Stellaria media), during the establishment year. We utilized open‐top chambers (OTCs) to manipulate air temperature in situ to impose three treatments: (1) constant warming (OTC present year‐round), (2) fluctuating warming (OTC present year‐round but temporarily removed prior to abrupt cold snaps), and (3) control (no OTC, ambient air temperature). OTCs increased air temperature within the alfalfa–orchardgrass canopy by an average of 0.45 and 0.72°C in Year 1 and Year 2, respectively; however, the effects of OTCs on air temperature varied temporally within and between years. Constant warming decreased alfalfa frost injury compared with the control, while the control and fluctuating warming resulted in similar levels of frost injury. Warmer temperature within the OTCs neither affected chickweed biomass nor the biomass of all other weed species. Both constant and fluctuating warming increased forage dry matter yield at the first harvest timepoint in the spring of both years, the period when preceding ambient air temperature tended to be cooler than other harvest timepoints. We found that the constant warming increased total forage yield (summed over the entire year) in Year 1, when precipitation was well above the 30‐year normal for our region, but decreased total forage yield in Year 2, when summer precipitation was substantially below the 30‐year normal. As global temperature continues to rise, yield loss of cool‐season perennial forages, such as alfalfa and orchardgrass, may be exacerbated in years without adequate precipitation. Therefore, exploring heat‐ and drought‐tolerant alternative forages, as well as management strategies that improve resilience to weather variability, will be increasingly important.

Low weed and cool‐season grass abundances likely necessary for warm‐season grass, forb, and shrub establishment

Plants seeded in degraded grasslands often fail to establish. In the Northern Great Plains, perennial cool‐season grasses are easiest to establish, and they sometimes competitively suppress warm‐season grasses, shrubs, and forbs. Seeding cool‐season grasses at low rates sometimes benefits other seeded plants but risks greater weed abundances. To identify grass seed rates low enough to allow other plants to establish but high enough to constrain weeds, we varied cool‐season grass seed rates while holding warm‐season grass, shrub, and forb seed rates fixed. The first couple growing seasons after seeding, we hypothesized cover of other seeded plants and weeds would decrease with increasing cool‐season grass seed rate. During later growing seasons, we hypothesized weed cover would become independent of grass seed rates due to seeded plants increasing in plots seeded at low rates. Neither hypothesis was supported. Because weed abundances were high, warm‐season grasses, shrubs, and forbs apparently experienced similarly intense competition regardless of grass rate, so low rates did not increase seeded plant establishment. Regardless of seed rate, cool‐season grass cover did not increase between the second and final (i.e. fourth) growing season, perhaps because of low precipitation. Increasing warm‐season grass, shrub, and forb abundances will require controlling weeds in addition to lowering cool‐season grass seed rates. Even these steps will not always increase establishment because native plants sometimes died before controlling weeds with herbicides became feasible and grass competition became important. Lowering grass rates without implementing weed control risks sites becoming weedy for prolonged periods.

How the Management and Environmental Conditions Affect the Weed Vegetation in Canary Grass (Phalaris canariensis L.) Fields

Canary grass (Phalaris canariensis L.) is a versatile crop with global significance; it is primarily cultivated for its small elliptical seeds, which are used as bird feed and for human consumption. This crop is adapted to various climates and soils, so it can be grown successfully in Hungary. However, challenges such as weed control, climate change impacts, and soil factors require strategic management for sustained success in canary grass cultivation. Our study investigated the impact of management and environmental (as seasonal and soil) factors on pre-harvest weed vegetation in canary grass fields in Southeast Hungary between 2017 and 2020. In addition to showing the weed vegetation of the canary grass, the aim of our work was to promote more effective weed management of canary grass by revealing correlations between soil, seasonality, and management variables, influencing weed diversity and coverage. Using the analysis of covariance (ANCOVA) and correlation tests, we tested significant variables, providing insights into the complex interactions affecting weed composition. A redundancy analysis (RDA) further unveiled the relationships between explanatory variables and weed species’ composition. The findings offer valuable information for effective weed management strategies in canary grass cultivation. Our comprehensive study on canary grass fields in Southeast Hungary sheds light on significant factors influencing weed composition and abundance. The average weed coverage was 10.8%, with summer annuals and creeping perennials being the most prevalent life forms. Echinochloa crus-galli, Cirsium arvense, Xanthium italicum, and Setaria viridis were among the dominant species. ANCOVAs revealed the impact of soil, management, and seasonal factors on weed cover, species richness, diversity, and yield levels. Soil properties like texture, pH, and nitrogen content showed varying effects on weed parameters. The vintage effect, tillage systems, and farming practices also played crucial roles. The redundancy analysis highlighted the influence of the year, soil sulfur content, and winter preceding crops on weed composition. In conclusion, the herbaceous vegetation in the studied area is dominated by summer germinating and creeping perennial species. Despite slight differences in average coverage and occurrence, a well-defined set of significant species is evident. Multicollinearity among variables suggests limitations to further increase the number of variables that can be included in the analysis. The ANCOVAs showed that the soil, seasonal, and farming variables significantly influence overall weed vegetation and crop yield, with a lesser impact on species richness and diversity. The reduced RDA model highlights the strong influence of the year on species’ composition, emphasizing the inherent factors during canary grass cultivation that are challenging to modify through farming practices.

Tezcalera, a traditional agricultural system that promotes native wild and agrestal germplasm conservation

Background: Traditional agricultural systems in Mesoamerica are adaptations of ancient farmers to the complex and varied environments. Tezcalera represents one of them. Questions: How is the environmental context under which the tezcalera develop? Which management practices are followed in tezcalera? How do these management practices affect weeds' richness, composition, and abundance? How do these management practices contribute to the resilience of the agricultural system, the tropical dry forests, and to the maintenance of subsistence resources? Studied species: Weeds growing in tezcaleras with different management. Study site and dates: Zumpahuacán, State of México, 2020-2021 Methods: Twenty-four collaborators were interviewed about the environmental, technological, and cultural aspects of tezcalera. We recorded weeds' richness, composition, and abundance in seven plots with different management histories. Results: Tezcaleras originate from the slash-burn process and follow different paths: tlacolol-milsol-shallow plot, potrero, and recently, Agave crop. We recorded 161 morphospecies from 45 botanical families; 95 % were native to tropical dry forests. Twenty-five species are endemic to the Balsas region, and thirty-four are at risk. Richness and abundance varied between tezcaleras, where tlacolol plots exhibited the highest values. Plant composition was similar; 65 % had intangible or tangible values. Conclusions: Tezcalera is a biocultural unit and a resilient agroecosystem. Traditional practices remain and positively impact the richness and composition of native weeds. The uncontrolled use of herbicides and the introduction of Agave crop are displacing traditional crops and modifying traditional practices, risking local agrobiodiversity.

Weed Ecology: Insights for Successful Management Strategies: A Review

In crop ecosystems, the primary challenge in establishing a long-term weed management strategy arise from a lack of understanding regarding the nature of weediness and the factors that contribute to species dominance. To address this, farmers and researchers often rely on quick and efficient, yet temporary weed control methods, which can lead to long-term issues. To develop a more effective and sustainable weed management approach, it is crucial to gain a comprehensive understanding of both the biological characteristics and ecological behaviours of weeds. This can be achieved by incorporating preventive techniques, scientific knowledge and management skills, with the goal of enhancing crop production and benefiting farmers. While further information is needed in all aspects of weed management, the primary objective of weed science is to increase our knowledge of weed biology and ecology, thus fostering a better understanding of weediness. This understanding will facilitate the adoption of appropriate management strategies instead of relying solely on short-term solutions that may create or exacerbate long-term problems. The successful growth and reproduction of any species depend on a variety of conditions. In a given ecosystem, the species that can thrive more efficiently under the specific set of environmental conditions will produce the most viable offspring and become the most abundant organisms. Weed ecology, which examines the adaptive mechanisms that enable weeds to thrive in highly disturbed soil conditions, provides essential insights into the distribution and abundance of weeds in both natural and managed systems. The occurrence of a weed in a particular area is influenced by multiple factors, with climatic, soil-related (edaphic) and biotic factors being the most significant among them.

The impact of herbicide-resistant canola systems on the weed community dynamics in the Canadian Prairies

Increased adoption of no-till and extensive cultivation of herbicide-resistant (HR) crops in low diversity rotations are some transformations that occurred during the 1970s–2000s in western Canada. Historical data analysis of weed survey data (Saskatchewan, Manitoba, and Alberta) in canola crops and a canola rotation field experiment were used to understand how tillage, herbicide-resistant cropping systems, and the temporal frequency of canola in the rotation can impact weed abundance, composition, and diversity in the Canadian prairies. Weed survey data revealed that the spatial frequency of many weed species declined in years after 1995 compared with before 1995, the year HR cultivars were introduced. False cleavers ( Galeum spurium L .) and volunteer wheat ( Triticum aestivum L.) were the only species showing a continuous increase in frequency throughout the surveyed years. Species richness showed no trajectories but varied depending on climatic conditions. Roundup-Ready (RR) systems were associated with green foxtail ( Setaria viridis L.) irrespective of their frequency in the rotation. Continuous canola systems had an obvious association with chickweed ( Stellaria media L.) regardless of herbicide systems. Wild oats ( Avena fatua L.) were predominant in the longer rotations with glufosinate and imidazolinone-resistant canola. In the field study, weeds associated before in crop herbicide application were relatively controlled after herbicides were applied, except for foxtail barley ( Hordeum Jubatum L.), which was not controlled in most HR systems. Overall, both weed survey data and field experiment data revealed greater control of most weed species due to the adoption of HR canola cultivars and the associated cultural practices.

Conservation agriculture and weed management effects on weed community and crop productivity of a rice-maize rotation

In recent years, an increase in weed infestation, which is adversely affecting crop growth and productivity has been a major challenge facing the farmers of South Asia. The adoption of a permanent bed in combination with residue retention-based crop management practices may reduce weed abundance and increase crop productivity. In a two-year field study, we evaluated the responses of different organic weed management practices with contrasting tillage and residue (R) management strategies to weed dynamics and crop productivity under rice-maize rotation. The main plot treatments consisted of zero-tillage direct seeded rice and zero-tillage maize (ZTR fb ZTM); ZTDSR and maize both on permanent raised beds with residue (PBDSR + R fb PBDSM + R); PBDSR and PBM without residue (PBDSR-R fb PBDSM-R) and conventional tillage puddled transplanted rice and conventional tillage maize (CTR fb CTM). The subplots comprised unweeded control; vermicompost mulch; P- enriched vermicompost mulch; live mulch with Sesbania spp. in rice and Pisum sativum in maize and weed-free. Total weed density and biomass in rice and maize at 30 days after sowing (DAS) were minimum for PBDSR + R fb PBDSM + R compared to remaining tillage and residue management practices in both years. Apart from weed-free treatment, the highest weed control index was found with live mulch. Yield of rice and maize were found higher in permanent beds along with residue retention-based practices. In rice, the weed-free treatment showed the highest grain yield and live mulch reported 9.8 and 6.8 % higher grain yield than vermicompost mulch and P-enriched vermicompost mulch respectively. Our study shows that conservation agriculture practices under rice-maize rotation is one of the ways to reduce weed density and improve crop productivity in South Asia and other similar agro-ecologies.

Trade-offs constrain the success of glyphosate-free farming

Glyphosate, the most widely used herbicide, is linked with environmental harm and there is a drive to replace it in agricultural systems. We model the impacts of discontinuing glyphosate use and replacing it with cultural control methods. We simulate winter wheat arable systems reliant on glyphosate and typical in northwest Europe. Removing glyphosate was projected to increase weed abundance, herbicide risk to the environment, and arable plant diversity and decrease food production. Weed communities with evolved resistance to non-glyphosate herbicides were not projected to be disproportionately affected by removing glyphosate, despite the lack of alternative herbicidal control options. Crop rotations with more spring cereals or grass leys for weed control increased arable plant diversity. Stale seedbed techniques such as delayed drilling and choosing ploughing instead of minimum tillage had varying effects on weed abundance, food production, and profitability. Ploughing was the most effective alternative to glyphosate for long-term weed control while maintaining production and profit. Our findings emphasize the need for careful consideration of trade-offs arising in scenarios where glyphosate is removed. Integrated Weed Management (IWM) with more use of cultural control methods offers the potential to reduce chemical use but is sensitive to seasonal variability and can incur negative environmental and economic impacts.

ВЛИЯНИЕ АГРОТЕХНОЛОГИЙ НА ФИТОСАНИТАРНОЕ СОСТОЯНИЕ ПОСЕВОВ И ПРОДУКТИВНОСТЬ СЕЛЬСКОХОЗЯЙСТВЕННЫХ КУЛЬТУР

The purpose of research is to establish the most effective technologies for cultivating crops in forage crop rotation based on their phytosanitary condition and productivity. The objects of research were crops of forage crops in crop rotation (annual and perennial grasses, grain crops, corn), cultivated using five technologies that differ in the intensity of nutrition backgrounds and the use of pesticides (extensive – control, intensive, high-intensity, organic, biologized). Research was conducted in 2018–2021 in a joint field experiment of the Yaroslavl Scientific Research Institute of livestock breeding and forage production – a branch of the Federal State Budget Scientific Institution “Federal Williams Research Center of Forage Production and Agroecology” and the Yaroslavl State Agrarian University to study phytosanitary indicators (the number and weight of weeds, potential contamination of the soil with their reproductive organs, the spread of diseases and the number of insect pests) and the productivity of cultivated crops using generally accepted methods. The research results made it possible to recommend perennial grasses for up to 3 years of use in fodder crop rotations in order to improve the phytosanitary condition of crops and corn in order to obtain high fodder productivity of the crop rotation (over 5 800 fodder units per 1 ha). For the cultivation of crops in this crop rotation, the use of organic technology using only organic fertilizers (cereal straw, manure at a rate of 60 t/ha for corn, green manure) is quite justified, since it helped reduce the abundance of weeds by 13.3–15.4 %, minimized the prevalence of diseases of grass and corn, reduced the number of insect pests by 9.7 % while obtaining an average increase in productivity of 26.8 % compared to the control and the absence of a significant reduction in comparison with intensive technologies while increasing the quality indicators of the crop and economic efficiency (profitability level – 132.9 %, return on additional costs – 4.86).

Weed infestation of narrow-leaved lupine crops in grain-grass-rowed crop rotation in the North-West of Russia

The results of the long term (2012–2018) study of weed infestation of green fallow fields with narrow-leaved lupin in the crop rotation including cereals, grasses and row crops in the North-West region of Russia (Leningrad region) are presented. The assessment of weediness in the narrow-leaved lupine variety Oligarch crops was carried out annually at 24 permanent survey sites (0.1 square meter). Based on the results of the surveys, the formation of a diverse and constant species composition of weeds (from 15 to 25 species), mainly of medium and severe degree of weediness (141–593 specimens per square meter), with the proportion of young plants ranging from 90.4 to 99.7 %. The mass species of weeds were lamb’s quarters, field pansy, corn spurry, hemp-nettles, fumitory, shepherd’s purse, prevalent perennial weeds were field sowthistle, coltsfoot, red sorrel, couch grass, marsh woundwort. The prevailing influence of weather conditions and individual characteristics on the weed infestation of narrow-leaved lupine crop has been determined. The combined effect of two factors was expressed by 47.7, 57.8 and 47.1 % in terms of species abundance, initial abundance and final phytomass of weeds, respectively. Long term application of mineral fertilizers led to an increase in the number of annuals (by 1.5–1.6 times) and a decrease in the density of growth of perennial weed species (by 1.6–1.9 times). The influence of the integrated plant protection system used in the crop rotation was manifested in a significant decrease in the density of perennial weed species (by 4.6 times) in narrow-leaved lupine crop.

Effects of Climate and Weeds on the Establishment of Thyme-Based Living Mulch Systems in Drylands of Cyprus

Backround: Mulching systems are at the spotlight of sustainable soil management as nature-based solutions for combating desertification.
 Aims: We tested how living mulch systems based on rainfed Thymbra capitata [(L.) Cav.], can be established under different pressure from drought and weeds in dryland carob plantations.
 Study design: 10 thyme plots in semi-arid climate (SKR); 11 plots in arid climate (VRY); different weed competition intensity (60 thymes per plot).
 Place and Duration of the Study: South-eastern Cyprus, between December 2019 and 2022.
 Methodology: Survival and soil cover for 1260 T. capitata seedlings (3-5 cm tall, 16 seedlings per m2) was assessed at the end of 3 dry seasons (d.s.) together with weed community composition, weed abundance (w.a.) and biomass. Climate data and De Martone’s Aridity Index (DMAI) were used to assess drought severity.
 Results: Around 80% of the thymes survived at the end of the first d.s, that followed a very rainy year (ca. 600 mm annual precipitation; P; ca. +50% than normal; ca. 19 DMAI). Thyme survival appeared unaffected by w.a. in both sites. After a severe drought that occurred the second year (ca. 300 mm P; ca. -22% than normal; ca. 9.5 DMAI) thyme survival rates dropped at the end of the d.s. to ca. 20% at the site with 3 times higher w.a./ biomass (mostly from Avena sp.). However, they were unaffected under low w.a. creating a 29% soil cover (vs.7% in VRY). These results remained till the end of the third d.s.
 Conclusions: To combat desertification and drought intensification under climatic change, rainfed T. capitata as living mulch appears unaffected by weeds during wet years, or in very dry years under low w.a. However, under high w.a., a weed management system is required if climate is arid.

Vertical tillage effects on crop production and pest management in Pennsylvania

AbstractWithin the last four decades, widespread transition to no‐till corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] production in Pennsylvania has improved soil conservation and soil quality but can result in residue and pest management challenges. To effectively manage residue in no‐till cropping systems, some growers have adopted vertical tillage, a residue management practice characterized by cutting and incorporating crop residue within the top 5–10 cm of soil. Despite few studies documenting effects on crop production and soil conservation, vertical tillage has become widespread. Replicated on‐farm trials were conducted over a 2‐year period in 2021–2022 to improve grower and consultant decision‐making regarding the role of vertical tillage relative to continuous no‐till on southeast Pennsylvania farms located within the environmentally sensitive Chesapeake Bay Watershed. We assessed the effects of vertical tillage on corn residue cover, winter annual weed abundance, slug damage, and soybean performance in 40 paired strip trials comparing spring vertical tillage to no‐till using three different vertical tillage tools used by farmer cooperators. Vertical tillage equipment type is a driver of variation in changes to surface residue cover. Baseline surface residue cover was similar among no‐till strips, but a greater proportion (32%) of strips had mean surface residue cover levels below a 60% conservation program compliance threshold when a Kuhn‐Krause Excelerator was used. Relative to no‐till, vertical tillage resulted in a 50% reduction in winter annual weed cover, a 24% reduction in slug damage, and no significant differences in soybean stand establishment or grain yield.

Dynamic changes in weed abundance and biodiversity following different green manure establishment

Weeds have a negative impact on agricultural production by competing with cultivated crops for resources and fostering conditions conducive to disease and insect pest dissemination. Hence, optimal weed management is of paramount importance for sustainable agricultural. In this study, the ability of four distinct green manure species to suppress weeds was determined in a field experiment conducted in Chongqing, Southwest China. After cultivating the green manure species, the weed density and diversity were monitored over the following year. The findings highlight a notable trend in the suppressive ability of green manures, with increased suppression observed from November to March, an optimal level observed from March to May, and a gradual decline observed thereafter. Poaceae (Lolium perenne L.) demonstrated the highest efficacy in suppressing weeds. The meta-analysis underscore the exceptional suppressive effects of poaceous green manures on weed as well and prove sustained planting for three or more consecutive years yielded superior weed suppression outcomes. Green manure had the most prominent inhibitory effect on poaceae weeds, followed by Polygonaceae and Caryophyllaceae. The field experiment also investigated the effect of green manures on weed community composition, they increased in the proportion of perennial weeds within these communities. This study offers valuable insights that can guide policymakers, agricultural experts, and farmers in devising effective weed management strategies. By highlighting the potential benefits of green manures and unraveling their nuanced impact, this study contributes to the arsenal of sustainable agricultural practices.

TRACES OF GLYPHOSATE IN CORN (Zea mays L.) AND AVOCADO (Persea americana Mill.) WEEDS SUPPORTED BY VANT AND RAMAN SPECTROSCOPY

Since the 1990s, radiometric and biophotonic sensor applications have provided reliable alternatives and rapid non-invasive diagnostics for the detection and delimitation of pests and diseases, as well as pesticide traces. Active sensors have been shown to be more accurate in detecting the heterogeneity of environmental factors based on thermal and infrared characteristics, chlorophyll fluorescence, and plant reflectance. Unmanned Aerial Vehicles (UAVs) equipped with infrared cameras locate and delimit weed abundance and diversity using Normalized Difference Vegetation Index (NDVI) algorithms, which highlight heterogeneous chlorophyll activity and herbicide-limited photosynthesis in crops. The resulting map serves as the foundation for collecting plant samples. In this study, the technology of these sensors was applied to determine glyphosate traces using Raman spectroscopy, which allowed a quick, low-cost, simple, and practical diagnosis with immediate results. These are essential characteristics for surveillance and monitoring activities, as well as the basis for a geo-referenced inventory of pesticides in production units. Of the 44 weed samples collected, eight were positive for glyphosate traces: two in corn and six in avocado. Weeds are identified as positive to glyphosate traces in Raman spectroscopy in the carotenoid and phenylpropanoid reduction ranges (1186 and 1213 cm-1) as a result of a decrease in the immune response. The vibrations presented by the amines in glyphosate and the C-OH of the carboxyl group are detected in the range of 1565 and 1567 cm-1.