Weed Biodiversity Research Articles

Convolutional neural network for the early identification of weeds: A technological support to biodiversity and yield losses mitigation

Weeds are a major constraint for crop production and food security. Chemical management, the most utilized method for weed control, has serious drawbacks. In this context, the development of more sustainable methods like site-specific weed management (SSWM) is highly deemed. With this study, we assessed the possibility of applying two convolutional neural networks (CNN) for the recognition of different classes of weeds in a winter wheat (T. aestivum) cultivation based on RGB images. By using this methodology, we were able to recognize with a high average precision (AP > 0.6) some species whose abundance and distribution in the field was correlated with the final wheat yield. We demonstrated that where the presence of R. raphanistrum, A. arvensis and P. rhoeas was high at the tillering stage and weed biodiversity indexes were low (Menhinich's Index, Simpson's Reciprocal Index and Shannon's Index), wheat yield was significantly reduced. In contrast, higher weed biodiversity mitigated yield losses. Therefore, CNN is a useful tool for early evaluation of the impact that weeds may have on yield, and it can be used as SSWM classifier for an early mapping of weeds, which is critical to improve our understanding of weed ecology dynamics in agricultural fields.

The Influence of Sugar Beet Cultivation Technologies on the Intensity and Species Biodiversity of Weeds

Sugar beet production is highly affected by weeds. The structure of crop rotation, the use of intercrops and different tillage techniques bring several benefits to sugar beet cultivation and create different living conditions for weeds. The response of weed communities in sugar beet stands has not been studied. The experimental plot is in the cadastral area of Ivanovice na Hané (Czech Republic). During an eight-year monitoring period (2013–2020), 46 weed species were identified. The dominant species was Chenopodium album. There were also summer and winter weeds. A more varied crop rotation increased the intensity of weed infestation, with winter weeds being the most common. On the contrary, a higher proportion of cereals in the crop structure favors the presence of summer weeds. The tillage technology and the inclusion of catch crops did not significantly affect the intensity of weed infestation in sugar beet stands or the spectrum of weed species. Current cropping technologies have driven the evolution of weeds. Due to their short life cycles and relatively simple genomes, weeds can respond very quickly to technological measures and, thus, change their harmfulness.

How Does Sustainable Management Practices Affect Weed Flora and Tuber Yield of Potato Crop in Mediterranean Environment?

AbstractIntensive potato cultivation affects weed species composition by selecting dominant and competitive weeds that represent a constraint of potato productivity. Field experiments were conducted during 2015 and 2016 growing seasons to examine the effects of soil tillage (plowing (PL), spading (SM), sub soiling (SS)) and fertilizer source (mineral (Min) and organic (Org)) on potato yield and weed community under Mediterranean environment. A randomized complete block design with three replications was adopted. Weed density and biomass were measured at the potato harvesting time. Weed density was highest in SS, intermediate in SM, and lowest in PL (43.8, 40.3, and 28.8 plants m−2). Similar trend was observed in weed biomass. Weed density and biomass were higher in Org than Min (42.1 vs. 36.4 plants m−2 and 129.6 vs. 117.9 g m−2, respectively). Perennial, monocot, and dicot weed species were the most abundant in subsoiling (13.1, 9.3 and 34.5 plants m−2). Density of perennial and dicot species were higher in Org than Min. Monocots were mostly linked with Min, while dicots were mainly associated with Org. Although tuber yield was higher in PL and Min (481.9 and 627.5 g m−2 of DM), it was affected by growing season and might be associated to SM and Org. Although the study shows that increased weed biodiversity in the system, achieved with more sustainable practices, proves to be an obstacle to potato production, the adoption of spading machine applied in combination with mineral and organic fertilizers could be a valid alternative to plowing. Further studies are required to develop sustainable agricultural techniques able to improve the competitive capacity of crops and reduce the selection of dominant weed species.

Multimodal remote sensing application for weed competition time series analysis in maize farmland ecosystems

Although weeds cause serious harm to crops through competition for resources, they also have ecological functions. We need to study the change law of competition between crops and weeds, and achieve scientific farmland weed management under the premise of protecting weed biodiversity. In the research, we perform a competitive experiment in Harbin, China, in 2021, with five periods of maize as the study subjects. Comprehensive competition indices (CCI-A) based on maize phenotypes were used to describe the dynamic processes and results of weeds competition. The relation between in structural and biochemical information of maize and weed competitive intensity (Levels 1–5) at different periods and the effects on yield parameters were analyzed. The results showed that the differences of maize plant height, stalk thickness, and N and P elements among different competition levels (Levels 1–5) changed significantly with increasing competition time. This directly resulted in 10%, 31%, 35% and 53% decrease in maize yield; and 3%, 7%, 9% and 15% decrease in hundred grain weight. Compared to the conventional competition indices, CCI-A had better dispersion in the last four periods and was more suitable for quantifying the time-series response of competition. Then, multi-source remote sensing technologies are applied to reveal the temporal response of spectral and lidar information to community competition. The first-order derivatives of the spectra indicate that the red edge (RE) of competition stressed plots biased in short-wave direction in each period. With increasing competition time, RE of Levels 1–5 shifted towards the long wave direction as a whole. The coefficients of variation of canopy height model (CHM) indicate that weed competition had a significant effect on CHM. Finally, the deep learning model with multimodal data (Mul-3DCNN) is created to achieve a large range of CCI-A predictions for different periods, and achieves a prediction accuracy of R2 = 0.85 and RMSE = 0.095. Overall, this study use of CCI-A indices combined with multimodal temporal remote sensing imagery and DL to achieve large scale prediction of weed competitiveness in different periods of maize.

Neutral weed communities: the intersection between crop productivity, biodiversity, and weed ecosystem services

AbstractWeeds are a fundamental component of agroecosystems and, if not appropriately managed, can cause severe crop yield losses. New perspectives on weed management are required, because current approaches, such as herbicide application or soil tillage, have significant environmental and agronomic drawbacks. We propose the concept of “neutral weed communities,” which are weed communities that coexist with crops and do not negatively affect crop yield and quality compared with weed-free conditions. Management practices that promote neutral weed communities can enable reduced use of herbicides and soil tillage while enhancing ecosystem services and biodiversity. We report scientific evidence of neutral weed communities and survey ecological explanations for why different weed communities have different effects on crop production. We also propose two weed management approaches for attaining neutral weed communities. The first approach aims to maximize weed biodiversity using traditional approaches such as cropping system diversification and integrated weed management. Higher weed biodiversity is associated with lower dominance of competitive weed species that reduce crop yield. The second approach relies on modern tools such as robots and biotechnology to manipulate the density of specific weed species. This approach can remove highly problematic species and minimize niche overlap between the weeds and crops. Given the complexity of interactions among crops, weeds, and other components of the agroecosystem, we highlight the need for multidisciplinary research to illuminate mechanisms that determine the neutrality of weed communities.

The biodiversity of weed communities of dent maize, narrow-leaved lupin and oat in relation to cropping system and weed control

The aim of the experiment was to assess the effect of cropping system and as well as various methods of weed control on the biodiversity of the weed community of dent maize, narrow-leaved lupine and spring oat. The data used in the study came from a three year field experiment carried out at the Experimental Station in south-eastern Poland (50°42'N, 23°16'E). The following factors were studied: 1. Cropping system – sole cropping and strip intercropping; 2. Weed control – mechanical and chemical. Changes in the diversity of the segetal flora are analysed using the species richness index (S), the Shannon-Wiener diversity index (H’), the Margalef index (R), the Simpson dominance index (D) and Pielou’s evenness index (J’). The use of chemical weed control increased the diversity of the weed community in all species tested compared to mechanical weed regulation. Chemical weed regulation significantly decreased the value of Simpson dominance index due to the limitation of the occurrence of dominant weed species. Strip intercropping increased weed biodiversity, however, the influence of cropping systems depended on the crop species and the weed controlmethod used.

Effects of Nitrogen Fertilization on Weed Flora and Productivity of Soybean [Glycine max (L.) Merr.] Crop

The literature suggests that nitrogen (N) fertilization increases yield in soybean. This study aimed to investigate the effects of N fertilization on: (i) The performance of soybean, and (ii) the weed flora. A two-year field experiment was carried out in Agrinio, Western Greece. The experiment was set up in a randomized complete block design, with four organic fertilizer treatments and six replications. The four treatments included 0 kg N ha−1 (N0/unfertilized control) and the application of 80 kg N ha−1, 100 kg N ha−1, and 120 kg N ha−1. The application of 120 N kg ha−1 resulted in the most notable increment of plant height (22.6–24%), biomass (10–13%), LAI values (14–17%), and yield (10–12%) compared to the N0. Compared to the N0, total weed biomass was increased by 26–32%, 34–49%, and 55–57% in N80, N100, and N120, respectively. The values of the H (Shannon), Dmg (Margalef), and J (Pielou) indices were unaffected by the fertilization, hence they did not affect weed biodiversity. CRI (crop resistance index), on the contrary, was negatively affected by N fertilization and was significantly reduced. Overall, our results indicate that the application of 80 kg N ha−1 is more efficient, can effectively improve the soybean performance, and enhance its yield.

Spring barley response to tillage systems and crop residues

The present study aimed to assess the effect of tillage systems and crop residues on grain yield and weed infestation of spring barley. The experiment was established with the method of randomized sub-blocks. The main experimental factor was the tillage system (TS): conventional tillage (CT), reduced tillage (RT), and no-tillage (NT). The second experimental factor included plots with crop residues (CR): straw (S) or without straw (WS). A higher grain yield of barley was determined in the RT than NT system. The RT system allowed producing a higher spike number and a higher 1000 grain weight. A higher grain yield was also obtained on the plots with straw (S) than without straw (WS). Greater weed density in barley stands was determined on RT and NT plots without crop residues (WS), whereas the lowest one was found on the CT plots with the residues (S). The air-dry weight of weeds was higher on the NT plots without crop residues (WS) than on the other plots, while the lowest air-dry weight of weeds was determined on the CT plots with the residues (S). The biodiversity of weeds in a barley stand was greater on the WS than on the S plots.

Diversity, Species, and Plant Growth Regulator and Nutrient Content of Local Weeds in Tawaeli Sub-District, Palu City, Indonesia

Each area has a variety and different types of weeds, the differences in each weed are caused by natural factors and human actions, including excessive pesticide spraying. This action can cause the chemical content, namely plant growth regulators and the nutrients in the weed plant to change and cause the quality of a soil to decrease. The research objective was to determine the level of diversity, species, and content of plant growth regulators and nutrient element measurements for local weeds. The research design was an exploration method in community agricultural land areas by recording the number of weeds found in agricultural land areas, trails, and irrigation edges in Tawaeli District, Palu City. Diversity analysis was using the exploration method, and the diversity index of medicinal plants was calculated using Shannon Wiener. The identification of weeds was carried out by UPT Herbarium (Tadulako University), plant growth regulators and nutrient content analysis were carried out using existing methods in the laboratory using local weed samples taken in the field. The results showed that there were 27 species of weeds grew on agricultural land in Tawaeli Sub-District, Palu City. These weed species belonging to 17 different plant families. Based on the category of diversity index, it was known that the biodiversity of weeds at the observation sites belongs to the low class (H' <1.00) and the medium class (H' >3.00). The conclusion was that in general, the high number of species and weed diversity were in the medium class H' category. Good nutrient content in weeds shows the potential of weeds as a source of important nutritional elements may benefit the growth and development of cultivated plants.

Living Mulch with Selected Herbs for Soil Management in Organic Apple Orchards

The establishment of living mulches in organic orchards could potentially improve the orchard biodiversity and, when specific plant species are selected, provide additional eco-services and functions, including adequate weed management. This study was conducted in an organically managed apple orchard in Skierniewice (Poland) to assess the effect of two selected living mulching species: Alchemilla vulgaris and Mentha piperita. They were assessed on weed control, weed biodiversity, tree nutritional status, root dry weight density (RDWD), and other root morphological traits compared to a natural soil cover (control). Overall, both living mulches produced 42.5% more dry biomass, increased weed species number (+29%), and increased soil coverage (+33%) compared to control mowed plots. The apple leaf chlorophyll index and nutrient content were higher in the presence of both living mulches than in the control. In addition, apple trees had 30–46% higher root dry weight densities, even though other root morphological traits were not affected by the treatments. The results suggested that the tree row can be managed with living mulches of herbs; these species have the potential to provide an additional income to the farmer, as well as beneficial effects for the orchard biodiversity, without impairing the tree root development and nutrient status.

Biodiversity of Weeds and Arthropods in Five Different Perennial Industrial Crops in Eastern Poland

A growing interest in the cultivation of non-food crops on marginal lands has been observed in recent years in Poland. Marginal lands are a refuge of agroecosystems biodiversity. The impact of the cultivation of perennial industrial plants on the biodiversity of weeds and arthropods have been assessed in this study. The biodiversity monitoring study, carried out for three years, included five perennial crops: miscanthus Miscanthus × giganteus, cup plant Silphium perfoliatum, black locust Robinia pseudoacacia, poplar Populus × maximowiczii, and willow Salix viminalis. As a control area, uncultivated fallow land was chosen. The experiment was set up in eastern Poland. A decrease in plant diversity was found for miscanthus and black locust. The diversity of arthropods was the lowest for the cup plant. No decrease in the number of melliferous plants and pollinators was observed, except for the miscanthus. The biodiversity of plants and arthropods was affected by the intensity of mechanical treatments, the fertilization dose, and the use of herbicides. The biodiversity also decreased with the age of plantation.

Soil Nitrogen and Weed Biodiversity: An Assessment under Two Orchard Floor Management Practices in a Nitrogen Vulnerable Zone in Italy

Nowadays, understory vegetation along the tree row is considered a vital source of agroecosystem services and functional biodiversity improvement in the fruit orchard. Hence, current orchard floor management systems encourage practicing a more sustainable approach that supports vegetation cover rather than keeping bare soil herbicide use, or tillage. A two-year field trial was conducted using two different ground management techniques; integrated mowing (mower and brush or disc) and herbicide (glyphosate) in two commercial apple and peach orchards in a nitrogen vulnerable zone (NVZ) of the Marche region, Italy. This study aimed to evaluate the effects of these practices on soil N status, weed abundance, percent of soil cover, and dry weed biomass production. Weed management systems had no significant effect on soil organic matter and N availability; however, an improvement was noticed under integrated mowing when compared to the one treated with herbicides. Integrated mowing had a significant effect on species richness, soil coverage, and weed biomass production, which was approximately 2-times higher than in the herbicide-treated plots. The overall results showed that integrated mowing maintained a balance in the soil N status of both orchards, while supporting above-ground weed biodiversity and soil protection.

Impacts of transgenic insect-resistant maize HGK60 with Cry1Ah gene on biodiversity of arthropods and weeds in the field.

Transgenic technology has developed rapidly in recent years. The environmental risk of the release of transgenic organisms is still a key issue. Research on the impacts on biodiversity is an effective way to objectively evaluate the risk. By taking transgenic maize HGK60 with insect-resis-tant gene Cry1Ah and common maize Zheng58 as control, we examined the diversity of arthropods and weeds in spring and winter of 2018 in Hainan Province. 43753 arthropods belonging to 69 species, 19 families, and 7 orders were obtained. There was no significant difference in arthropod community composition, structure and ecological indices between HGK60 and Zheng58. Compared with Zheng58, the transgenic insect-resistant maize HGK60 had obvious resistance to wood boring beetles. 16 species of weeds belonging to 8 families were recorded in the field. There was no significant difference in the density and ecological indices of weeds between HGK60 and Zheng58, with almost the same change trends in the whole growth period. Our results suggested that planting transgenic maize HGK60 with insect-resistant gene Cry1Ah did not affect biodiversity of arthropods and weeds. The results provided scientific support for the further studies of environmental risk of transgenic crops.

Biodiversity of Weeds in Fields of Grain in South-Eastern Poland

Analysis of weed infestation of selected fields of grain (winter wheat, spring wheat, spring triticale) was conducted between 2013 and 2016 in five commercial farms in south-eastern Poland (49°52’ N, 21°46’ E) based on a quantitative and qualitative (quadrat) method and an agro-phytosociological method. The quadrat analysis was conducted prior to weeding procedures, and the agro-phytosociological analysis by grain harvest. The biodiversity of weed communities was measured with the Shannon and Simpson indices. The degree of weed infestation of grain species was significantly differentiated by weeding procedures carried out by farmers. The highest share of weeds in grain crops included dicot weeds (80.6–86.4% of all species, depending on location), and the remaining weed groups were a much smaller issue. The greatest weed infestation was found in spring triticale, and the smallest in winter wheat. The highest Shannon biodiversity index was recorded in the field of triticale, and the lowest in the field of winter wheat. The Simpson index points to the greatest biodiversity in fields of triticale and the smallest in fields of spring wheat. The conducted research will help categorize segetal flora characteristics for a given crop, determine its quantity and species composition, and evaluate biodiversity of weeds in fields of grain.

Effects of weed biodiversity on the ecosystem service of weed seed predation along a farming intensity gradient

Weed biodiversity plays a key role in supporting food webs and ecosystem services in agroecosystems. One important service, that reduces weed abundance, is the predation of weed seeds by invertebrates and vertebrates. In this context weed biodiversity may be supportive in maintaining seed predator prevalence. This however, can be highly influenced by farming systems. In the present study we examined the connections between weed diversity, carabid beetle diversity and weed seed predation (WSP) rate. Additionally, the influence of a farming intensity gradient on WSP rate and predator groups was evaluated. An on-farm experiment on the Eastern Swabian Alps was set up from 2015 to 2017, where we determined the weed diversity, carabid beetle diversity using pitfall traps and WSP rates and predator groups by utilizing seed cards and exclosure cages. There was a linear correlation between weed diversity and carabid beetle diversity as well as a pattern showing that intermediate diversity of carabid beetles (3–8 species) exhibited the highest WSP rates by invertebrates. However, a direct connection between weed diversity and WSP was not detected. Farming intensity had no consistent influence on WSP, rather year and specific agronomic measures like cover cropping most presumably affected WSP. Carabid beetle communities were similar in 2016 and 2017 with omnivorous species dominating in the conventional fields and granivorous species in extensively managed fields. The most efficient seed predators were vertebrates. The promotion of beneficial predators and ecosystem services like WSP is possible by designing appropriate management strategies. Key components of these strategies should be the conservation of plant diversity and the utilization of weed control strategies such as cover cropping that provide suitable habitats for beneficial predators.

Weed control efficiency and productivity in rice-fish-duck integrated farming system

Rice farming integrated with fish and ducks potentially provides ecological services and supports effective management of weeds which cause rice yield losses due to growth competitiveness with the available resources and productivity. Present study investigated the efficacy of integrating fish and duck in rice farming for controlling weed infestations and their impacts on productivity and economics of the system. Appraisal on diversity of weeds indicated that grassy weeds (Echinochola colona, Echinochola crusgalli) and sedges (Cyperus difformis, Cyperus iria, Fimbristylis miliacea) were prevalent in rice during tillering stages, while broad leaf (Ludwigia adscendens, Sphenoclea zeylanica) and aquatic weeds (Marsilia quadrifolia, Otellia alismoides, Vallisneria spiralis, Limnophila indica, Ceratophyllum demersum, Hydrilla verticillata) were abundant during active tillering and panicle initiation stages of rice. A significant reduction in weed density and weed biomass was observed in rice-fish (RF), rice-duck (RD) and rice-fish - duck (RFD) integration. However, weed control efficiency (WCE %) was significantly (p<0.05) higher in RFD. The weed biodiversity in terms of species richness (Simpson’s index) and species diversity (Shannon-Wiener index) decreased significantly, while Pielou evenness community index increased in RFD, signifying weed community composition was highly diversified with reduction of formerly dominant weed species. Rice agronomic characteristics, productivity and economic returns were higher in integrated system indicating over all improvements in ecology and productivity. Better growth of fishes accrued with RFD integrated system, possibly, due to the better nutrient availability. Thus, fish and duck can be used as bio-control agents for weed management in rice farming for enhancing productivity in areas where application of chemical herbicides may be partially or totally eliminated in transplanted lowland system.

Organic but Also Low-Input Conventional Farming Systems Support High Biodiversity of Weed Species in Winter Cereals

In recent years, the European Union has been paying particular attention to the problem of biodiversity loss. The possibilities of its assessment and conservation are included in the latest European Union (EU) policies and reflected in the European Biodiversity Strategy. The biodiversity of weeds in winter cereals in organic and conventional low-input farms in Eastern Poland was investigated during a 3-year period. Significantly more species and larger abundance were found in organic than in conventional farming systems. The biodiversity of these communities was described by Shannon’s diversity and Simpson’s dominance indices, which showed diversity to be well maintained in both farming systems; however, significantly higher Shannon’s index and significantly lower Simpson’s index values were observed in organic farms. Both farming systems were the mainstay of endangered and rare species, as well as some invasive weed species. Weed communities of organic farms were dominated mostly by Setaria pumila and Elymus repens, while conventional farms were dominated by Juncus bufonius and Setaria pumila. The study showed the importance of organic farming systems for biodiversity conservation. It was also shown that low-input (traditional) conventional farms are also beneficial for biodiversity conservation.

The Evaluation of Intercropping System of Indigo (Indigofera tinctoria L.) and Roselle (Hibiscus sabdariffa L.) on Yield, Weed Biodiversity and Changes of Weeds Community

The Evaluation of Intercropping System of Indigo (Indigofera tinctoria L.) and Roselle (Hibiscus sabdariffa L.) on Yield, Weed Biodiversity and Changes of Weeds Community

Studies on Weed Diversity and Phytosociology in Wheat Crop

Rice-wheat is the dominant cropping system in Patna district where wheat is generally grown in winter season and a large area is sown by using seed drill machines. The present investigation is based on the study of biodiversity of weeds under zero tilled condition in Patna district of Bihar. The weed inventory surveys and phytosociological studies in wheat fields were conducted during 2016-19 to identify the weed flora composition, density, frequency and Importance value index of 30 major weed species in wheat. In the study, Asteraceae was found as the largest family in respect of weed species whereas Poaceae and Leguminosaefamilystood at the second position in terms of weed species. Phytosociological studies further revealed that Phalaris minor (6.48) and Cynodon dactylon (5.03) have larger relative frequency among other weed species while Chenopodiumalbum(5.18)and Avena fatua(4.44)have larger relative abundance in the study area. Studies on relative density of weeds revealed that densities of Phalaris minor (7.06) and Chenopodium album (5.65) were higher over other weed species and similar trends were also observed in respect of Importance value index of weeds. Therefore, while planning effective weed management strategy, these two weeds (P. minor and C. album) must be focused. The study will provide an appraisal of species through quantitative characters and will allow effective weed management decision.

Improving soil health, weed management and nitrogen dynamics by Trifolium subterraneum cover cropping

The low organic matter and nitrogen levels in the soils, as well as the high weed pressure, typical of Mediterranean agroecosystems, necessitate a valid and sustainable alternative management. The utilization of cover crops such as Trifolium subterraneum L. may represent an innovative and efficient option for low-input and organic agricultural systems. In a 3-year experiment, we evaluated the effect of T. subterraneum and spontaneous flora cover cropping, with or without burying dead mulch into the soil, on the quali-quantitative composition of the weed seed bank in an apricot orchard. Moreover, the bacteria Nitrosomonas europaea and Azotobacter vinelandii, involved in the soil N cycle, and the content of ammoniacal and nitric soil nitrogen were quantified. For the first time, we demonstrated that T. subterraneum cover cropping with the incorporation of dead mulches into the soil on the one hand reduced weed biodiversity and the seed bank size (− 70% compared to conventional management following the standard commercial practices), while, on the other hand, increased the amount of N. europaea (+ 109%), A. vinelandii (+ 145%), NH4+ (+ 137%) and NO3− (+ 478%) in the soil. This approach was therefore found to be a major improvement in low-input agriculture and organic farming, and it can be applied in Mediterranean orchards as an eco-friendly strategy with the aim of reducing synthetic herbicides for weed control and mineral nitrogen fertilizers as the sole source of nitrogen supply.