Herbicide Application Research Articles

Weed density evaluation using KCCA-CFBLS based on fusion of visual and tactile features in special paddy field environment

Accurately evaluating weed density in paddy fields is crucial for achieving high-quality control of rice weeds, as it enables precise application of herbicides or matching of mechanical weeding intensity. However, visual methods alone may not provide ideal classification of weed density in specialized paddy field environments due to complex backgrounds, environmental interference, and visual occlusion. In this study, we propose an innovative method that combines vision and tactile features to achieve accurate weed density evaluation. We first obtained tactile data containing weed density information using a self-made tactile sensor, while simultaneously capturing corresponding visual images. We then utilized the kernel canonical correlation analysis (KCCA) algorithm to maximize the correlation of discriminating features extracted from the tactile data and visual images, and obtained fusion eigenvectors that characterize the weed density. These eigenvectors were used as input for a broad learning system (BLS), in which the random feature mapping was replaced by a cascade feature node to construct a KCCA-based cascade feature broad learning system (KCCA-CFBLS). Our method achieved accurate evaluation of weed density in low, medium, and high weed conditions using a novel weed dataset from a specialized paddy field environment. We analyzed the accuracy and running time, and found that KCCA-CFBLS outperformed methods based on SVM and YOLOv5-Lite, achieving 11.56% and 7.56% higher accuracy, respectively, with less time consumption. Experimental results demonstrated significant advantages of our method in terms of accuracy and real-time performance compared to visual methods, providing a decision-making basis for the implementation of intelligent chemical and mechanical weeding in specialized paddy field environments.

Mechanical Weed Control: Sensor-Based Inter-Row Hoeing in Sugar Beet (Beta vulgaris L.) in the Transylvanian Depression

Precision agriculture is about applying solutions that serve to obtain a high yield from the optimization of resources and the development of technologies based on the collection and use of precise data. Precision agriculture, including camera-guided row detection and hydraulic steering, is often used as an alternative because crop damage can be decreased and driving speed can be increased, comparable to herbicide applications. The effects of different approaches, such as uncontrolled (UC), mechanical weed control (MWC), herbicide weed control (HWC), and mechanical + herbicide control (MWC + HWC), on weed density and yield of sugar beet were tested and evaluated in two trials (2021 and 2022) in South Transylvania Depression at the tested intervals BBCH 19 and 31. Weed control efficacy (WCE) depends on the emergence of the weeds and a good timing of weed controls in all the trials and methods, though the highest yield of sugar beet roots was recorded in the treatment MWC + HWC, with an increase up to 12–15% (56.48 t ha−1) yield from HWC (50.22 t ha−1) and a yield increase of more than 35–40% than MWC (42.34 t ha−1). Our trials show that it is possible to increase yield and have fewer chemical applications with the introduction of new precision technologies in agriculture, including sensor-guided mechanical controls.

Chemical Control Against Aggressive Broad Leaves Weed Ipomea sp. in Drill Seeded-rice (Oryza sativa L.)

Two field experiments were carried out at the Experimental Farm of Rice Department, Sakha Agricultural Research Station, Kafrelsheikh, Egypt throughout 2020 and 2021 summer seasons to identify an efficient chemical control program against Ipomea sp. as perennial Convolvulaceae weed in drill seeded-rice. The experimental design was split-plot with three replications. Three times of herbicidal application at 20, 30 and 40 days after sowing (DAS) were allocated randomly in main plots, while in sub-plots, six weed control treatments were randomly distributed included three single herbicides application (bentazone at rate of 1.714 kg ai ha-1, fluroxypyr at rate of 0.0952 kg ai ha-1 and bensulfuron-methyl at rate of 0.0714 kg ai ha-1) in addition to two herbicide mixtures were bentazone + fluroxypyr (1.344 kg ai ha-1 + 0.0952 kg ai ha-1) and bensulfuron + fluroxypyr (0.0714 kg ai ha-1 + 0.0952 kg ai ha-1) as compared to un-treated (weedy check) plots. Chemical control at early stage (20 DAS) achieved the best Ipomea control and recorded the lowest values of tillers number m-2, fresh and dry weights during 2020 and 2021, consequently recorded the highest rice dry matter, panicles number m-2, panicle weight and grain yield during both seasons. The results also showed that herbicide mixtures exceeded single application of herbicide in controlling Ipomea as broad leaf weed, bentazon + fluroxypyr ranked first in weed control efficiency percentage and recorded the lowest weed density m-2, fresh and dry weights of Ipomea during the two seasons of study as well as achieved the best values in rice dry matter, panicles per square meter, panicle weight and grain yield during 2020 and 2021 seasons, while the mixture of bensulfuron + fluroxypyr ranked second in this respect. The combination of bentazone + fluroxypyr sprayed at 20 DAS recorded the best Ipomea chemical control efficiency (95.4 %) and recorded the best rice grain yield (9.322 t ha-1) as an average for Giza 178 cv under drill seeded-rice conditions.

Weed detection in soybean fields using improved YOLOv7 and evaluating herbicide reduction efficacy.

With the increasing environmental awareness and the demand for sustainable agriculture, herbicide reduction has become an important goal. Accurate and efficient weed detection in soybean fields is the key to test the effectiveness of herbicide application, but current technologies and methods still have some problems in terms of accuracy and efficiency, such as relying on manual detection and poor adaptability to some complex environments. Therefore, in this study, weeding experiments in soybean fields with reduced herbicide application, including four levels, were carried out, and an unmanned aerial vehicle (UAV) was utilized to obtain field images. We proposed a weed detection model-YOLOv7-FWeed-based on improved YOLOv7, adopted F-ReLU as the activation function of the convolution module, and added the MaxPool multihead self-attention (M-MHSA) module to enhance the recognition accuracy of weeds. We continuously monitored changes in soybean leaf area and dry matter weight after herbicide reduction as a reflection of soybean growth at optimal herbicide application levels. The results showed that the herbicide application level of electrostatic spraying + 10% reduction could be used for weeding in soybean fields, and YOLOv7-FWeed was higher than YOLOv7 and YOLOv7-enhanced in all the evaluation indexes. The precision of the model was 0.9496, the recall was 0.9125, the F1 was 0.9307, and the mAP was 0.9662. The results of continuous monitoring of soybean leaf area and dry matter weight showed that herbicide reduction could effectively control weed growth and would not hinder soybean growth. This study can provide a more accurate, efficient, and intelligent solution for weed detection in soybean fields, thus promoting herbicide reduction and providing guidance for exploring efficient herbicide application techniques.

Economical Evaluation of Reduced Herbicide Doses Application Rates to Control Phalaris brachystachys (Short-Spiked Canary Grass) in a Biennial Wheat-Sunflower Rotation in Mediterranean Dryland: A Modelling Approach.

Phalaris brachystachys (short-spiked canary grass) is considered to be among the most troublesome cereal weeds in Mediterranean areas. A bioeconomic model, based on population dynamics, competition and economic sub-models, was developed to simulate the long-term economic consequence of using herbicide-based strategies: no herbicide application, full herbicide dose (standard rate) and two reduced dose rates (75 and 50% of the standard rate) to control P. brachystachys in a biennial wheat-sunflower rotation. Simulation results indicated that only herbicide application at a full dose (90% control) and 3/4 dose (80% control) produced positive economic results, with the full dose being the best strategy (EUR 98.65 ha-1 year-1). A sensitivity analysis showed that the economic outcome, in terms of annualized net return, was strongly influenced by changes in yield, price, and fixed costs. In addition, the annualized net return was more sensitive to parameter changes at reduced herbicide doses than at full rate. In the wheat-sunflower rotation system, the application of the full dose of herbicide was the most economical and stable strategy in the long-term. Reduced doses are not a recommended option from an economic point of view. Bioeconomic models provide practical insight into different management approaches for effective weed control.

Early treatment effects on plantation growth and biodiversity in mature ponderosa pine forest

We address the concerns that managed forest plantations may cause reductions of diversity of understory vegetation. We performed inventories of two mature ponderosa pine plantations in which multiple treatments were applied during plantation establishment. At stand age 35, we measured tree heights and diameters, understory plant cover and diversity, soil nutrients and chemical properties, and soil microbial biomass and diversity with phospholipid fatty acid. We found a significant, positive effect from both herbicide (H) and fertilizer (F) applications on subsequent overstory tree growth and development ( P < 0.05); insecticide (I) effect was minimal. We observed negative effects on understory plant diversity decades later when herbicide was applied during stand establishment. However, lower plant diversity and ground cover appeared to have been caused primarily from overstory canopy closure, supported by the increased understory cover and diversity observed in the HI and HFI plots that had been thinned at age 12. Similarly, while fertilizer increased tree growth at both sites, it only negatively affected understory plants at the higher quality site. We did not find significant influence of treatment effects on soil nutrients and microbial communities. Therefore, to mitigate the potential loss of understory biodiversity in plantations, foresters can manage overstory trees with traditional pre-commercial thinning techniques and early tending.

Management of Herbicide-Resistant Common Lambsquarters, Chenopodium album , in Atlantic Canada

Abstract Common lambsquarters ( Chenopodium album ) is one of the most troublesome annual broadleaf weeds in potato production in Atlantic Canada. Historically controlled by a combination of cultivation and herbicides, potato producers now often rely on a single herbicide application to provide season long control of common lambsquarters. The reliance on a few herbicides for common lambsquarters control has led to widespread incidence of herbicide resistance in this species, negatively impacting potato yield. This case study explores common lambsquarters’ biology, development of herbicide resistance, and the evolving management practices including chemical, cultural, and mechanical to help mitigate its impact on potato productivity. Information © The Author 2024

Soil quality and microbial communities in subtropical slope lands under different agricultural management practices.

Land degradation is a major threat to ecosystem. Long-term conventional farming practices can lead to severe soil degradation and a decline in crop productivity, which are challenging for both local and global communities. This study was conducted to clarify the responses on soil physicochemical properties and microbial communities to changes in farming practices. Slope land orchards under three agricultural management practices-conventional farming (CF), organic farming (OF), and ecofriendly farming (EFF)-were included in this study. We found that soil carbon stock increased by 3.6 and 5.1 times in surface soils (0-30 cm) under EFF and OF treatments, respectively. EFF and OF significantly increased the contents of total nitrogen by 0.33-0.46 g/kg, ammonia-N by 3.0-7.3 g/kg, and microbial biomass carbon by 0.56-1.04 g/kg but reduced those of pH by 0.6 units at least, and available phosphorous by 104-114 mg/kg. The application of phosphorous-containing herbicides and chemical fertilizers might increase the contents of phosphorous and nitrate in CF soil. High abundances of Acidobacteria and Actinobacteria were observed in EFF and OF soils, likely because of phosphorous deficiency in these soils. The abundance of fungi in OF soil indicated that plants' demand for available soil phosphorous induced the fungus-mediated mineralization of organic phosphorous. High abundances of Gammaproteobacteria, Planctomycetes, Firmicutes, and Nitrospirae were observed in CF soil, possibly because of the regular use of herbicides containing phosphorous and chemical fertilizers containing high total nitrogen contents.

Comparative study of influence of water stress on effectiveness of sulfosulfuron to two species of weeds through biomass and photo-physiological parameters

Drought may affect the effectiveness of herbicides. However, our knowledge about the interaction between drought and the response of different species to the application of herbicides is limited. Dose-response experiments were conducted on two major weeds of wheat fields to investigate the water stress effects on sulfosulfuron effectiveness. At the 2-leaf stage, Hordeum spontaneum and Sinapis arvensis were subjected to two irrigation regimes (10 and 65% of the available water depletion) and 7 days later, the plants were exposed to sulfosulfuron doses (0, 50, 100, 200, 400, 800% of the recommended dose). The biochemical and physiological responses of the plants were investigated 10 days later. H. spontaneum showed lower sensitivity to the herbicide than S. arvensis. Water stress decreased the efficiency of sulfosulfuron on both species with a greater effect on H. spontaneum. The herbicide required to induce 90% reduction of total dry mass (ED90) in water-stressed H. spontaneum was 63248.0 g ai ha−1 (2377.7 times the recommended dose of herbicide), and this amount was 10.74 times the ED90 value in irrigated plants. The ED90 of sulfosulfuron to reduce the total dry mass of irrigated and water-stressed S. arvensis was 1022.4 and 1862.9 g ai ha−1, respectively. Water stress alleviated chlorophyll decline in herbicide-treated H. spontaneum, but induced chlorophyll degradation in S. arvensis and decreased Fv/Fm in both species. The results suggested that higher doses of sulfosulfuron are recommended for use in arid conditions to effectively manage weeds, particularly those exhibiting reduced sensitivity to the herbicide.

Herbicide application impacted soil microbial community composition and biochemical properties in a flooded rice field

Herbicide application is a common practice in intensive agriculture. However, accumulating herbicide residues in the ecosystem affects important soil attributes. The effect of two herbicides, pendimethalin and pretilachlor, on soil biochemical properties and microbial community composition was studied in a transplanted paddy field. Results reveal a gradual decline in herbicide residue up to 60 days after application. Changes in soil microbiological and biochemical properties (microbial biomass, enzymes, respiration, etc.) showed an inconsistent pattern across the treatments. Quantitative polymerase chain reaction analysis showed the archaeal, bacterial and fungal populations to be of higher order in control soil compared to the treated one. Amplicon sequencing (16S rRNA and ITS genes) exhibited that besides the unclassified genera, ammonia-oxidizing Crenarchaeota and the group represented by Candidatus Nitrososphaera were dominant in both the control and treated samples. Other archaeal genera viz. Methanosarcina and Bathyarchaeia showed a slight decrease in relative abundance of control (0.5 %) compared to the treated soil (0.7 %). Irrespective of treatments, the majority of bacterial genera comprised unclassified and uncultured species, accounting for >64–75 % in the control group and over 78.29 % in the treated samples. Members of Vicinamibacteraceae, Bacillus and Bryobacter were dominant in control samples. Dominant fungal genera belonging to unclassified groups comprised Curvularia, Aspergillus, and Emericellopsis in the control group, whereas Paraphysoderma and Emericellopsis in the herbicide-treated groups. Inconsistent response of soil properties and microbial community composition is evident from the present study, suggesting that the recommended dose of herbicides might not result in any significant change in microbial community composition. The findings of this investigation will help in the formulation of a framework for risk assessment and maintaining sustainable rice cultivation in herbicide- amended soils.

Performance of Post-Emergence Herbicide Combinations on Weed Management and Crop Yield in Direct Seeded Rice (Oryza sativa L.)

Direct-seeded rice (DSR), an innovative alternative to traditional transplanting, has gained popularity for its cost-effectiveness and labour-saving attributes. Weeds pose a significant threat to DSR. In this study, the effectiveness of various weed management methods, including hand weeding and herbicide applications, was evaluated. Hand weeding proved most effective in controlling weeds, while specific herbicides, such as bispyribac sodium + pyrazosulfuron (T2) and triafamone + ethoxysulfuron (T6) applied at 16 days after sowing (DAS), demonstrated superior weed control efficiency, improved growth parameters, and enhanced yield. Paspalum distichum was effectively controlled by penoxsulam + cyhalofop-butyl (T7). The study emphasizes the importance of customizing weed control to local conditions, with the choice of suitable herbicides and practices aligning with prevalent weed biotypes in the specific farming system. Understanding the nuanced impacts of post-emergence herbicides is crucial in navigating the intricate landscape of weed management in direct-seeded rice.

Effect of Ready Mix Application of Herbicide on Weed Dynamics and Productivity of Maize in Lateritic Belt of West Bengal

Background: Maize, being highly productive and versatile cereal crop, is influenced by various biotic and abiotic stresses. Among biotic stresses, weed infestation is one of the serious concerns in maize cultivation. Weeds can affect maize by competing for light, water and nutrients resulting in yield loss of up to 70% in severe cases. Methods: A field experiment was conducted during kharif season for two consecutive years of 2019 and 2020 in agriculture farm of Palli Siksha Bhavana (Institute of Agriculture), Visva-Bharati, Sriniketan, West Bengal, India. The experiment was laid out in randomized block design and replicated thrice. The experiment comprised of seven weed management treatments viz. T1 (tembotrione 9% + atrazine 45% WG @ 1000 g/ha), T2 (tembotrione 9% + atrazine 45% WG @ 1250 g/ha), T3 (tembotrione 9% + atrazine 45% WG @ 1500 g/ha), T4 (Tembotrione 34.4% SC @ 286 ml/ha), T5 (Atrazine 50% WP), T6 (Hand weeding), T7 (Weedy check). Result: Experimental results revealed that among different herbicide mixtures, tembotrione + atrazine 1500 g/ha was found to be effective in suppressing the weeds growth and found no residual effect on soil chemical and biological properties during both the years of the experiment.

A influência de 2,4-D e dicamba na fisiologia de mudas de oliveira

Abstract The objective of this work was to evaluate the influence of herbicides 2,4-D and dicamba on the physiological response of chlorophyll a in olive (Olea europaea) seedlings. The following eight rates of the 2,4 D (670 g a.e. ha-1) and dicamba (720 g a.e. ha-1) herbicides were applied: 0, 1.56, 3.13, 6.25, 12, 25, 50, and 100% of the recommended for burndown. The herbicides were applied at 80 cm above the seedlings using a CO2 pressurized back sprayer with a 150 L ha-1 spray volume. Plant gas exchange was measured using a portable infrared gas analyzer. Chlorophyll a fluorescence was evaluated using a portable modulated light fluorometer. The application of both herbicides caused a decrease in the process of CO2 assimilation in the plants, reducing net photosynthesis and stomatal conductance. The 2,4-D herbicide caused the most severe effects on the variables related to chlorophyll a fluorescence. Low values of maximum quantic yield were observed after the application of the herbicides, of which dicamba was the most harmful. Both herbicides damage the photosynthetic apparatus of olive seedlings.

An intelligent spraying system for weeds in wheat fields based on a dynamic model of droplets impacting wheat leaves.

Targeted herbicide application refers to precise application of herbicides in weed-infested areas according to the location and density of farmland weeds. At present, targeted herbicide application in wheat fields generally faces problems including the low herbicide adhesion rate, leading to omission and excessive loss of herbicides. To solve these problems, changes in the impact force of herbicide and the weed leaves in the operation process of a spraying system were studied from the interaction between weeds and herbicides applied. A dynamic model of weed leaves was established. On this basis, the research indicated that the herbicide adhesion rate is highest under spraying pressure of 0.4 MPa and flow rate of 0.011 kg/s when the spray height is 300 mm. To study the dynamic deformation of weed leaves and the distribution of liquid herbicides in the external flow field under weed-herbicide interaction, a dynamic simulation model of herbicide application was built using the finite element method. The results show that when the spray height is 300 mm, the maximum weed leaf deformation index (LDI) is 0.43 and the velocity in the external flow field is 0 m/s under spraying pressure of 0.4 MPa and flow rate of 0.011 kg/s. This finding indicates that the herbicide is not splashed elsewhere and the turbulence intensity in the weed area is 2%, implying steady flow of the herbicide, most of which can be retained on weed leaves. Field test results of application quality of the herbicide show that the maximum LDI is 0.41 and the coverage of the herbicide in the sheltered area below the leaves is 19.02% when the spraying pressure is 0.4 MPa, flow rate is 0.011 kg/s, and spray height is 300 mm. This solves the problem of a low rate of utilization of herbicides because the herbicide passes through weed plants, and achieves the precision herbicide application in wheat fields.

Weed communities after decades of mineral fertilization and tillage treatments in a corn–soybean rotation

Abstract Soil fertility and disturbance can potentially modify weed dynamics in a corn–soybean rotation. Knowing how added mineral fertilizers and tillage influence weed populations in the long term can provide insight into weed community shifts, which may affect future weed management requirements. The first objective of this study was to evaluate the effect of 24 to 25 years of nitrogen and phosphorus fertilization treatments and tillage (moldboard vs. no-till) on weeds (density, biomass, and composition) before and after herbicide applications in 2016/corn and 2017/soybean. The second objective was to evaluate the effect of the same treatments 6 yr after no postemergence weed management in 2022/corn. Since the last evaluation performed in 2004, weed density, richness, and diversity increased, and more annual grasses were observed under both tillage regimes. No fertilization effect was observed on any weed variables, including composition, except for increased biomass when left to grow all season after crop planting. In managed plots, the density and biomass of annuals and perennials were generally higher in no-till, and discrepancies were highest for annual grass densities before herbicide application. Weed species richness and diversity based on counts were equivalent between tillage regimes, but total biomass was distributed between more species in no-till. Higher weed densities and concurrent weed biomass, observed in no-till, reduced crop yields in 2016/soybean only. The combination of low crop diversity and low use of residual herbicides during the trial potentially led to the observed species shifts and increased weed density.

When the specialization is a curse: distribution of Lolium remotum Schrank in Slovakia

Distribution of Lolium remotum in Slovakia, a typical linicolous weed, is presented in this paper. The species was recorded in 30 quadrants of the Central European mapping grid; the most of localities were found in the Carpathians which is related to the areas of flax cultivation for the linen industry. While in the 19th century it was relatively common in flax fields, after the First World War it began to decline (flax sown areas decreased by three quarters in former Czechoslovakia during the world economic crisis of 1929-1933). In the second half of 20th century, the synergistic effect of several agrotechnical measures (precise cleaning of the seed, simplification of crop rotation, deep autumn plowing and application of herbicides) manifested; only single locality was documented. At present, it belongs to the extinct species of Slovak flora (RE), it has not been detected for over 60 years.

Influência da época de aplicação de 2,4-D e saflufenacil na qualidade de sementes de azevém (Lolium multiflorum)

ABSTRACT: Italian ryegrass (Lolium multiflorum Lam.) is considered one of the main winter cover crops in southern Brazil; however, it is a weed species with a record of being resistant to several herbicides. The settlement of this species in agricultural areas occurs through the seed bank in the soil, and measures that interfere with seed production can assist in its management. The present study evaluated the phytotoxicity, production, and quality of Italian ryegrass seeds through the application of herbicides 2,4-D and saflufenacil at different stages of development. Three trials were conducted, a completely randomized experimental design for the first two and randomized blocks for the third, all with four replications. The treatments were arranged in a 3x3 factorial scheme, in which factor A was composed of the herbicides saflufenacil (35 g a.i. ha-1), 2,4-D (1005 g a.e. ha-1), plus control without application; and factor B consisted of the booting, anthesis, and maturation Italian ryegrass development stages. The phytotoxicity of the herbicides to Italian ryegrass did not exceed 30%, with saflufenacil causing the greatest injury at anthesis. There was a reduction in Italian ryegrass seed yield when herbicides 2,4-D and saflufenacil were applied, and the application of 2,4-D and saflufenacil at anthesis reduced the percentage of full seeds. The number of empty Italian ryegrass seeds was higher when saflufenacil was applied at anthesis. The application of 2,4-D at maturity reduced Italian ryegrass germination and radicle length. From this perspective, these herbicides can help reduce the production and quality of Italian ryegrass seeds.

Emergence timing of smallflower umbrella sedge (Cyperus difformis), barnyardgrass (Echinochloa crus-galli), and bearded sprangletop (Leptochloa fusca spp. fascicularis) in California water-seeded rice

Abstract Late-season weed emergence in California rice fields complicates decisions concerning the timing of control measures. The objective of this study was to predict the emergence of three problematic weed species in rice using thermal time models. Smallflower umbrella sedge, barnyardgrass, and bearded sprangletop seedlings were counted and removed daily at three locations across the Sacramento Valley rice-growing region in 2018. The accumulation of thermal time (growing degree days; GDD) commenced with the initial flooding of the fields at each location, utilizing the specific base temperatures corresponding to each species. The pattern of emergence as a function of GDD was modeled with a Weibull function. Root-mean-square values for comparing actual and model-predicted cumulative emergence values were 6% to 23%. Percent cumulative emergence initially increased rapidly for smallflower umbrella sedge and reached 90% emergence with accumulation of 13 GDD. Barnyardgrass emerged after smallflower umbrella sedge and reached 90% emergence with an accumulation of 124 GDD. Bearded sprangletop had a delay of 64 GDD compared to barnyardgrass to reach first emergence and reached 90% emergence at 215 GDD. The period of weed emergence at all field sites differed across the three species and led to a continuous spectrum of weed emergence over time. This study characterizes the emergence of three economically important rice weeds and provides useful information for the timing of weed management. Typical herbicide applications on the day of seeding may have less efficacy on the late-emerging weeds, causing reduced weed control. Delayed herbicide application, overlay of residual herbicides, or use of herbicides with longer residual activity are suggested to control late-emerging weeds.

Integrated management of cheat (Bromus secalinus L.) and downy brome (Bromus tectorum L.) in Oklahoma grain-only winter wheat

Abstract In Oklahoma, downy brome and cheat are difficult-to-control winter annual grasses. In the past, cheat infested most of the winter wheat hectares harvested in Oklahoma. Biotypes that are cross-resistant to acetolactate synthase–inhibiting herbicides have left growers with minimal management options for conventional and herbicide-tolerant systems. Field trials near Lahoma, Oklahoma, in 2019–2020 and 2020–2021 evaluated integrated management of cheat and downy brome using three strategies: planting date (optimal, delayed, and late), cultivar selection (high and low competitiveness), and herbicide choice (no herbicide, sulfosulfuron at 35.2 g ai ha−1 and pyroxsulam at 18.4 g ai ha−1). Visual control, weed species present, wheat biomass at heading, and grain yield data were collected. In 2019–2020, 8 to 9 wk after treatment, visual control increased by 15% with the delayed planting compared with the optimal planting date and 14% with the late planting date. In 2020–2021, similar control (∼99%) was recorded for delayed and late plantings with 23% greater control than the optimal timing. Due to a lack of weed coverage, weed biomass in 2019–2020 had no response to planting date, cultivar, or herbicide treatment. Downy brome biomass during 2020–2021 was approximately 90% lower with delayed to late planting dates than the optimal planting date. In the same year, downy brome and cheat biomass were low (≤0.4 and 0.2 g m−2) and 98% less after an herbicide application than a nontreated area. Wheat grain yield at the optimal planting date was greater than yields from delayed and late plantings in 2019–2020. A delay in planting from the optimal date to delayed or late timings decreased wheat yield by 14% and 21%, respectively. In 2020–2021, wheat yield from the late planting was reduced by 57% compared with the optimal planting yield. Delaying the planting date and the use of a common herbicide can suppress cheat and downy brome, but a decline in wheat yield may occur.

Native establishment improved and weed competition reduced by topsoil removal in direct‐sown native grasslands

SummaryAustralian temperate grasslands are among its most threatened plant communities. In agricultural landscapes, major barriers to their recovery are high soil nutrient levels that favour the growth of exotic pasture and other non‐native species, high standing weed biomass creating fierce aboveground competition, and rich weed seed and bud banks providing dense emergent seedling competition. Therefore, the return of grasslands to arable landscapes through restoration must rely on overcoming these challenges, ideally by reducing soil nutrients and mitigating the effects of weeds. This study demonstrates the effectiveness of topsoil removal for restoring diverse native grassy communities by direct seeding on sites with a legacy of elevated soil nutrients and competitive exotic vegetation. Conversely, it showed that repeated shallow cultivation (four times over 12 months) to stimulate weed emergence, followed each time by herbicide application, failed to achieve this outcome, at least in the short term (three years). Grassy community restoration is imperative in Australia, but importantly, it must utilise restoration protocols that are as effective as possible so that limited time, money, and resources are not wasted. In this light, the technique of topsoil manipulation may take us one step closer to achieving this goal in agricultural locations, where their loss is most pronounced.