Herbicide Application Methods Research Articles

Targeted weed management of Palmer amaranth using robotics and deep learning (YOLOv7).

Effective weed management is a significant challenge in agronomic crops which necessitates innovative solutions to reduce negative environmental impacts and minimize crop damage. Traditional methods often rely on indiscriminate herbicide application, which lacks precision and sustainability. To address this critical need, this study demonstrated an AI-enabled robotic system, Weeding robot, designed for targeted weed management. Palmer amaranth (Amaranthus palmeri S. Watson) was selected as it is the most troublesome weed in Nebraska. We developed the full stack (vision, hardware, software, robotic platform, and AI model) for precision spraying using YOLOv7, a state-of-the-art object detection deep learning technique. The Weeding robot achieved an average of 60.4% precision and 62% recall in real-time weed identification and spot spraying with the developed gantry-based sprayer system. The Weeding robot successfully identified Palmer amaranth across diverse growth stages in controlled outdoor conditions. This study demonstrates the potential of AI-enabled robotic systems for targeted weed management, offering a more precise and sustainable alternative to traditional herbicide application methods.

Effects of Various Herbicide Types and Doses, Tillage Systems, and Nitrogen Rates on CO2 Emissions from Agricultural Land: A Literature Review

Although herbicides are essential for global agriculture and controlling weeds, they impact soil microbial communities and CO2 emissions. However, the effects of herbicides, tillage systems, and nitrogen fertilisation on CO2 emissions under different environmental conditions are poorly understood. This review explores how various agricultural practices and inputs affect CO2 emissions and addresses the impact of pest-management strategies, tillage systems, and nitrogen fertiliser usage on CO2 emissions using multiple databases. Key findings indicate that both increased and decreased tendencies in greenhouse gas (GHG) emissions were observed, depending on the herbicide type, dose, soil properties, and application methods. Several studies reported a positive correlation between CO2 emissions and increased agricultural production. Combining herbicides with other methods effectively controls emissions with minimal chemical inputs. Conservation practices like no-tillage were more effective than conventional tillage in mitigating carbon emissions. Integrated pest management, conservation tillage, and nitrogen fertiliser rate optimisation were shown to reduce herbicide use and soil greenhouse gas emissions. Fertilisers are similarly important; depending on the dosage, they may support yield or harm the soil. Fertiliser benefits are contingent on appropriate management practices for specific soil and field conditions. This review highlights the significance of adaptable management strategies that consider local environmental conditions and can guide future studies and inform policies to promote sustainable agriculture practices worldwide.

Evaluation of methods used to improve grasslands as ring‐necked pheasant brood habitat

AbstractRing‐necked pheasant (Phasianus colchicus) demographic response is sensitive to chick survival and nest success. The establishment and management of grasslands within agricultural landscapes, often through cropland conversion programs (e.g., Conservation Reserve Program [CRP]), have positive impacts on survival and nest success. Newly established CRP and early successional habitat can provide vegetative structure selected by pheasant chicks. Ideal brood habitat provides an abundance of arthropods, an open understory promoting efficient chick movement, and a protective canopy cover. However, the natural succession of grasslands changes desired vegetative structure and challenges managers with providing adequate habitat for pheasant chicks. We investigated the efficacy of different methods of CRP management, including haying, burning, herbicide application, interseeding, and grazing, to provide adequate brood rearing habitat in cool‐ and warm‐season grasslands. We assessed chick body mass change using human‐imprinted ring‐necked pheasant chicks and investigated changes in vegetation composition and structure in relation to various habitat treatments in north‐central and north‐eastern South Dakota during mid‐June and mid‐July of 2013, 2014, and 2015. Generally, treatments that incorporated interseeding, herbicide application, or their combination had the greatest chick mass gain, reduced litter cover and depth, and increased bare ground and forb cover. Effective management for brood habitat may require more aggressive techniques than simple haying or prescribed fire techniques.

Reducing herbicide input and optimizing spray method can minimize nontarget impacts on native grassland plant species.

Invasive plants threaten biodiversity worldwide and effective management must control the target invader while conserving biodiversity. Herbicide is often used to control invasive plants, but potential negative impacts on biodiversity have led to spot spraying being recommended over boom spraying to minimize the exposure of nontarget species to chemicals. We examined the influence of herbicide application methods on off-target plant communities in threatened temperate grasslands of southeastern Australia, where spraying with the broadleaf herbicide fluroxypr is commonly used to control St. John's wort, Hypericum perforatum L. It is well established that fluroxypr effectively controls H. perforatum but few studies have examined its impact on native forbs. A spray drift experiment using water-sensitive cards indicated that ground surface coverage was higher for spot spraying (91%-99%) than for boom spraying (5%-31%). We established a replicated, 3-year, before-after-control-impact experiment across 48 1-m2 quadrats to determine how three herbicide application methods (spot spray, fine boom and coarse boom) affected nontarget native forbs, the group most likely to be affected by broadleaf herbicides. This experiment was conducted in grasslands where H. perforatum was almost absent, so responses would reflect the direct impacts of the chemical, rather than structural changes resulting from removal of the target invader. Spot spraying decreased the probability of occurrence of native leguminous forbs, while increasing the occurrence of exotic leguminous forbs and the richness of all exotic species and exotic annual forbs. Spot spraying reduced the occurrence of the native Desmodium varians and the abundance of the native Chrysocephalum apiculatum. During this 3-year study, native species appeared to be impacted either directly by fluroxypr or indirectly by increased competition with exotic species. Where herbicide application is deemed crucial in these grasslands, we recommend boom spraying when H. perforatum density is moderate to high. Spot spraying should only be used when the density of H. perforatum is very low. Given the regional variation in H. perforatum density, the spatial scale of invasion, soil depth, and conservation values, we present a decision tree to assist managers in evaluating the costs and benefits of chemical control, indicating situations where alternative or modified methods could be used.

Uticaj primene herbicida u trake i međuredne kultivacije na svežu masu širokolisnih korova u usevu soje

Aim of the research was to determine whether the band application of herbicides in soybean, covering a 50% smaller herbicide area, in combination with inter-row cultivation can achieve a similar or approximate weed control effectiveness, as compared to the broadcast herbicide application method in soybean crops, with and without inter-row cultivation. In three-year trials, pre-emergence (dimethenamid-P + metribuzin) and post-emergence (bentazon + imazamox) herbicides were applied using the broadcast and band (25 cm wide) application of herbicides, with and without inter-row cultivation.Inter-row cultivation was applied one week after the first and second post-emergence treatments. Impact of the tested variants on the fresh aboveground biomass of weeds was assessed, with the following species being dominant: Abutilon theophrasti Medik., Amaranthus retroflexus L., Ambrosia artemisiifolia L., Chenopodium album L., and Xanthium strumarium L. The results showed that using the band application of herbicides with inter-row cultivation can achieve approximate effectiveness in reducing fresh biomass compared to broadcast application of herbicides, with or without inter-row cultivation. The combination of pre-emergence herbicides and the two-time application of divided amounts of post-emergence band and broadcast application of herbicides with inter-row cultivation achieved the most reliable control of all weeds, with an efficiency >95%. The results indicate that under favorable conditions for the herbicide action, it is possible to omit one half of the total amount of applied post-emergence herbicides. This can further contribute to significantly reducing the total amount of herbicides used in weed control.

Comparison of Plant Detection Performance of CNN-based Single-stage and Two-stage Models for Precision Agriculture

The fact that arable land is not increasing in proportion to the ever-increasing population will increase the need for food in the coming years. For this reason, it is necessary to increase the yield of crops to make optimum use of arable land. One of the most important reasons for the decrease in yield and quality of crops is weeds. Herbicides are generally preferred for weed management. Due to deficiencies in herbicide application methods, only 0.015-6% of herbicides reach their target. The use of herbicides, which is an important part of the agricultural system, is an issue that needs to be emphasized, considering the risk of residue and environmental damage. In parallel with the rapid development of electronic and computer technologies, artificial intelligence applications have had the opportunity to develop. In this context, the use of artificial intelligence for plant detection in the subsystems of herbicide application machines will contribute to the development of precision agriculture techniques. In this study, the plant detection performances of single-stage and two-stage Convolutional Neural Network (CNN)-based deep learning (DL) models are evaluated. In this context, a dataset was created by taking images of Zea mays, Rhaponticum repens (L.) Hidalgo, and Chenopodium album L. plants in agricultural lands in Konya. With this dataset, the training of the models was carried out by the transfer learning method. The evaluation metrics of the trained models were calculated using the error matrix. In addition, training time and prediction time were used as quantitative metrics in the evaluation of the models. The plant detection performance, training time, and prediction time of the models were 85%, 8 h, 1.21 s for SSD MobileNet v2 and 99%, 22 h, 2.32 s for Faster R-CNN Inception v2, respectively. According to these results, Faster R-CNN Inception v2 is outperform in terms of accuracy. However, in cases where training time and prediction time are important, the SSD MobileNet v2 model can be trained with more data to increase its accuracy.

Influence of seeding rates and herbicide application methods on weed infestation and oil radish seed yield

The article presents the results of the research carried out to determine the influence of seeding rates and herbicides application methods on the weed infestation and the seed yield of a new variety of oilseed radish in the conditions of the forest-steppe of the Central Federal District of Russia. The study was carried out during the period from 2019 to 2021 at the Lipetsk Rapeseed Research Institute. The scheme of a two-factor field experiment included the options where in certain conditions (factor A) – with or without herbicide application (in the phase of 5-7 true leaves), the seeding rates of germinating seeds (factor B) were studied - 0.5, 1.0; 1.5; 2.0; 2.5 million pieces/ha. The soil in the experimental plots was leached medium-thick heavy loamy chernozem. During the years of the experiment, the applications of herbicides significantly reduced the number of weeds in the agrocoenosis, and the decrease in the seeding rate caused the opposite effect. During the flowering phase, oilseed radish weed infestation, at the studied seeding rates in the conditions with no chemical plant protection products applied, decreased by 47-57%, and in the conditions when chemical plant protection products had been applied – the index decreased by 74-84%. At the same time, the differences in the number of weed plants between the studied seeding rates decreased. By the end of the growing season, the phytosanitary state of this crop generally improved, and this was most noticeable with the variants that included herbicide application. It has been determined that an increase in the seeding rate within the studied limits reduced the crop yield, and the chemical protection of the plants from weeds, on the contrary, significantly increased it. Consequently, the largest seed yield of a new variety of oilseed radish Alpha was provided by the cultivation technology, where a seeding rate was 0.5 million units/ha and herbicides were applied.

Research on weed identification method in rice fields based on UAV remote sensing.

Rice is the world's most important food crop and is of great importance to ensure world food security. In the rice cultivation process, weeds are a key factor that affects rice production. Weeds in the field compete with rice for sunlight, water, nutrients, and other resources, thus affecting the quality and yield of rice. The chemical treatment of weeds in rice fields using herbicides suffers from the problem of sloppy herbicide application methods. In most cases, farmers do not consider the distribution of weeds in paddy fields, but use uniform doses for uniform spraying of the whole field. Excessive use of herbicides not only pollutes the environment and causes soil and water pollution, but also leaves residues of herbicides on the crop, affecting the quality of rice. In this study, we created a weed identification index based on UAV multispectral images and constructed the WDVI NIR vegetation index from the reflectance of three bands, RE, G, and NIR. WDVI NIR was compared with five traditional vegetation indices, NDVI, LCI, NDRE, and OSAVI, and the results showed that WDVI NIR was the most effective for weed identification and could clearly distinguish weeds from rice, water cotton, and soil. The weed identification method based on WDVI NIR was constructed, and the weed index identification results were subjected to small patch removal and clustering processing operations to produce weed identification vector results. The results of the weed identification vector were verified using the confusion matrix accuracy verification method and the results showed that the weed identification accuracy could reach 93.47%, and the Kappa coefficient was 0.859. This study provides a new method for weed identification in rice fields.

The diversity of microfungi associated with grasses in the Sporobolus indicus complex in Queensland, Australia.

There are five closely related Sporobolus species, collectively known as weedy Sporobolus grasses (WSG) or the rat's tail grasses. They are fast growing, highly competitive, unpalatable weeds of pastures, roadsides and woodlands. An effective biological control agent would be a welcomed alternative to successive herbicide application and manual removal methods. This study describes the initial exploratory phase of isolating and identifying native Australian microfungi associated with WSG, prior to evaluating their efficacy as inundative biological control agents. Accurate species-level identification of plant-pathogenic microfungi associated with WSG is an essential first step in the evaluation and prioritisation of pathogenicity bioassays. Starting with more than 79 unique fungal morphotypes isolated from diseased Sporobolus grasses in Queensland, Australia, we employed multi-locus phylogenetic analyses to classify these isolates into 54 fungal taxa. These taxa belong to 22 Ascomycete families (12 orders), of which the majority fall within the Pleosporales (>24 taxa in 7 families). In the next phase of the study, the putative species identities of these taxa will allow us to prioritise those which are likely to be pathogenic based on existing literature and their known ecological roles. This study represents the first step in a systematic, high-throughput approach to finding potential plant pathogenic biological control agents.

Early evaluation of adjuvant effects on topramezone efficacy under different temperature conditions using chlorophyll fluorescence tests

Proper selection of adjuvant applications is an important strategy to enhance herbicide efficacy and reduce active ingredient input especially under adverse environmental conditions. In this study, a two-factor split-plot-design experiment was conducted to evaluate the effects of two adjuvants on the efficacy of topramezone on the grassy weed species giant foxtail (Setaria faberi Herrm.) and the broadleaved weed species velvetleaf (Abutilon theophrasti Medik.) under three different temperature conditions. The two tested adjuvants were methylated seed oil (MSO) and organosilicone. Three temperature levels, 35/30°C, 25/20°C, and 15/10°C (day/night), were used in the laboratory and greenhouse experiment. Plant chlorophyll fluorescence measurements shortly after herbicide application and classic whole-plant bioassay methods were used to evaluate the herbicide efficacy among the different treatments. Results indicated that the maximum quantum efficiency (Fv/Fm) of the top leaf of the weeds treated with topramezone mixed with MSO was significantly lower than that of the weeds treated with topramezone mixed with organosilicone and without an adjuvant at 2–3 days after treatment under all three temperature levels. The herbicide response of the plants treated with topramezone mixed with organosilicone and topramezone alone was not significantly different. These results corresponded well with the results of the classic whole-plant test. MSO has been shown to be good at enhancing the efficacy of topramezone on these weed species under all three temperature conditions. The measurement of chlorophyll fluorescence is a promising technique for evaluating the effects of adjuvants on the efficacy of herbicides shortly after herbicide treatment.

Microbial rhizosphere communities in response to chlorimuron-ethyl herbicide in soils under alfafa crop

Biolog Eco technology was used to investigate the effects of different chemical herbicide application methods, such as pre-emergence after sowing and post-emergence (stem and leaf spraying), on the characteristics of carbon source utilization by microbial communities in alfalfa rhizosphere soil. The averages of well color development (AWCD) and microbial metabolism diversity indices of post-emergence herbicide spraying on stems and leaves were significantly lower than those of pre-emergence herbicide and without herbicide treatments. Furthermore, pre-emergence after sowing herbicide treatment did [...]

Strip spraying technology for precise herbicide application in carrot fields

Abstract The aim of this empirical field research was to show potential differences due to the precise application of herbicides in the quality and size of the carrot root yield and the amount of working liquid used compared to those for control samples. Empirical verification of the effectiveness of the developed technology, confirmed by statistical analyses of the obtained results, allows for a comparative assessment of this method with the conventional method of herbicide application used in this study. Due to the methodology used, it can be assumed that for carrots, the years were a random factor, and the experiments carried out were a series. It can be assumed that in the analysis of a series of experiments, for each of the examined features there are no differences between the groups and there is no interaction of the groups with the years. The yields of the groups weeded manually, sprayed in a conventional way, and weeded with precise spraying did not differ in a statistically significant way. In the precise application, a 20–30% lower herbicide consumption was observed, which has an impact on the protection of the environment and improves the economic effect of carrot production.

Efficiency evaluation of oil flax cultivation under different methods of herbicide application

The article presents long-term research (2018-2020) on the effect of herbicide tank mixtures Herbitox, SC (1.0 l/ha) and Miura, EC (1.2 l/ha); Cleo, WDG (0.12 kg/ha) and Miura, EC (1.2 l/ha), as well as of the separate application of these preparations on the productivity of oil flax (variety FLIZ of the breeding of V.S. Pustovoit All-Russian Research Institute of Oil Crops) in the zone of unstable moistening on leached chernozem of the Western Ciscaucasia. We established that on average for three years, in case of treatment of oil flax with a tank mixture of herbicides Herbitox, SC (1.0 l/ha) and Miura, EC (1.2 l/ha); Cleo, WDG (0.12 kg/ha) and Miura, EC (1.2 l/ha), we got higher yields compared to their separate application – 1.39 and 1.37 t/ha, respectively, oil yield – 0.55 t/ha; there was high net income of 21629 and 21004 rub/ha with a profitability of 80 and 78 %, respectively.

Deep Learning-Based Object Detection System for Identifying Weeds Using UAS Imagery

Current methods of broadcast herbicide application cause a negative environmental and economic impact. Computer vision methods, specifically those related to object detection, have been reported to aid in site-specific weed management procedures for targeted herbicide application within a field. However, a major challenge to developing a weed detection system is the requirement for a properly annotated database to differentiate between weeds and crops under field conditions. This research involved creating an annotated database of 374 red, green, and blue (RGB) color images organized into monocot and dicot weed classes. The images were acquired from corn and soybean research plots located in north-central Indiana using an unmanned aerial system (UAS) flown at 30 and 10 m heights above ground level (AGL). A total of 25,560 individual weed instances were manually annotated. The annotated database consisted of four different subsets (Training Image Sets 1–4) to train the You Only Look Once version 3 (YOLOv3) deep learning model for five separate experiments. The best results were observed with Training Image Set 4, consisting of images acquired at 10 m AGL. For monocot and dicot weeds, respectively, an average precision (AP) score of 91.48 % and 86.13% was observed at a 25% IoU threshold (AP @ T = 0.25), as well as 63.37% and 45.13% at a 50% IoU threshold (AP @ T = 0.5). This research has demonstrated a need to develop large, annotated weed databases to evaluate deep learning models for weed identification under field conditions. It also affirms the findings of other limited research studies utilizing object detection for weed identification under field conditions.

Herbicide selectivity on macauba seedlings and weed control efficiency

Seedlings of macauba (Acrocomia aculeata (Jacq.) Lodd. ex Mart.) palm spend ∼10 months in nursery before being taken to the field. Since there are no registered herbicides for macauba, weed control in seedling containers is done manually; however, macauba leaves have thorns that injure workers' hands. In this work, the selectivity of indaziflam, isoxaflutol, oxyfluorfen and sulfentrazone was evaluated on macauba seedlings produced in nurseries, incorporated (INC) to the substrate and/or applied before (PRE) and after (POST) transplantation, as well as its efficacy for the weed control. Seedlings were no intoxicated by the herbicides regardless of the application method. However, considering the height, leaf area and dry weight and root volume, the INC and PRE applications of indaziflam were not selective for macauba. In contrast, POST-indaziflam applications stimulated the growth of seedlings (<100 cm), being even greater than the control (75 cm) at 10 months. Regarding weed control, the INC treatments lost effectiveness up to 40 % from 14 to 56 days after application (DAA), except indaziflam which maintained a control above 95 %. Weed control of PRE applications decreased up to 60 % for all four herbicides, while the POST applications of indaziflam, oxyfluorfen and sulfentrazone maintained control levels ≥80 % at the same period. Weed presence reduced the growth rate of macauba seedlings by ∼40 % (32 cm high in the non-weeding control vs 55 cm in the weeding control) at 126 DAA. In addition, weeds reduced the growth of seedlings in most treatments, since the plant height was similar to the non-weeding control. Isoxaflutole, oxyfluorfen and sulfentrazone were selective for macauba seedlings, regardless of the herbicide application method. Indaziflam was selective for seedlings only in POST applications. The evaluated herbicides were efficient in controlling most weed species up to 56 DAA in PRE and POST applications.

Optimising spot weed control regimes forPinus radiataplantations

Spot spraying, in which only the area around individual trees is treated, is an important method of herbicide application during establishment of Pinus radiata D. Don (radiata pine) in New Zealand. Minimising the spot size reduces costs and has possible environmental benefits from reduced overall herbicide use. An analysis of six experiments at five separate sites tested the growth response of P. radiata to spot weed control on sites dominated by herbaceous vegetation, usually as a result of oversowing with a mixture of grasses and legumes. The analysis showed that, on sites dominated by herbaceous weeds, the reduction in rotation length achieved by applying total weed control compared with no postplant weed control ranged from 0.4 to 1.6 years and averaged 0.9 years. A spot diameter of 1 m maintained for 1 year achieved 28% of the benefit of total weed control, whereas a spot diameter of 2 m maintained for 1 year achieved 66% of the benefit. Generally, there was little benefit in maintaining spots beyond 1 year. An economic analysis indicated that weed control of any kind was generally unprofitable when the time-shift gain from weed control was 0.4 years or less but highly profitable for sites with a time shift of 1.6 years or more.

Nitrates content in table potato tubers under the influence of herbicides and biostimulants

ABSTRACTThe objective of the study was to determine the effect of herbicides and biostimulants on the potato tuber content of nitrates. The experimental material consisted of tubers harvested in a field experiment which examined the following factors: three medium early potato cultivars (Bartek, Gawin, Honorata) and five methods of herbicide and biostimulant application (Harrier 295 ZC (linuron + chlomazon), Sencor 70 WG (metribuzin), growth regulator Kelpak SL (algae extract from Ecklonia maxima − auxins and gibberellins), growth regulator Asahi SL (sodium para-nitrophenol, sodium ortho-nitrophenol, sodium 5-nitroguaiacol) and a control unit where weeds were mechanically controlled). The tuber content of nitrates was determined in fresh matter with an ion-selective nitrate electrode and silver–silver chloride reference electrode. Herbicides and biostimulants increased the potato tuber content of nitrates compared with control tubers. However, they did not pose a threat to consumer health. Tubers of plants sprayed with the herbicide Sencor 70 WG (metribuzin) and the biostimulant Asahi SL (sodium para-nitrophenol, sodium ortho-nitrophenol, sodium 5-nitroguaiacol) contained the most nitrates whose accumulation was also affected by cultivars and weather conditions in the study years.

Status quo of chemical weed control in rice in sub-Saharan Africa

If future rice production is to contribute to food security for the increasing population of sub-Saharan Africa (SSA), effective strategies are needed to control weeds, the crop’s fiercest competitors for resources. To gain better insights into farmers’ access to, and use of, herbicides as part of weed control strategies, surveys were conducted in key rice production locations across SSA. Farm surveys were held among 1965 farmers across 20 countries to collect data on rice yields, farmer’s weed management practices, herbicide use, frequencies of interventions and information sources regarding herbicides. Markets were surveyed across 17 countries to collect data on herbicide availability, brand names and local prices (converted to US$ ha−1). Herbicides are used by 34% of the rice farmers in SSA, but adoption ranges from 0 to 72% across countries. Herbicides are more often used by men (40%) than by women (27%) and more often in irrigated (44% of farmers) than in rainfed lowland (36%) or upland rice growing environments (24%). Herbicides are always used supplementary to hand weeding. Following this combination, yield loss reductions in irrigated lowlands and rainfed uplands are estimated to be 0.4 t ha−1 higher than hand weeding alone. In rainfed lowlands no benefits were observed from herbicide use. Sixty-two percent of the herbicides sold at rural agro-chemical supply markets are unauthorized. These markets are dominated by glyphosate and 2,4-D, sold under 55 and 41 different brand names, respectively, and at relatively competitive prices (below average herbicide price of US $17 ha−1). They are also the most popular herbicides among farmers. For advice on herbicide application methods, farmers primarily rely on their peers, and only a few receive advice from extension services (<23%) or inform themselves by reading the product label (<16%). Herbicide application timings are therefore often (38%) sub-optimal. Herbicide technologies can contribute to reduced production losses in rice in SSA. However, through negative effects on crop, environment and human health, incorrect herbicide use may unintentionally counteract efforts to increase food security. Moving away from this status quo will require strict implementation and monitoring of national pesticide regulations and investment in research and development to innovate and diversify the currently followed weed management strategies, agricultural service provision and communications with farmers.

Iron and manganese content and uptake with the yield of potato tubers as affected by herbicides and biostimulants, and potato tuber nutritional value

The study material consisted of table potato tubers produced in a three-year field experiment. The following factors were examined: three potato cultivars – Bartek, Gawin and Honorata, five herbicide application methods: herbicides alone (Harrier 295 ZC and Sencor 70 WG) and mixed with growth regulators (Harrier 295 ZC + Kelpak SL, Sencor 70 WG + Asahi SL), and a control unit where weeds were mechanically controlled. The objective of the study was to assess the effect of herbicides and their mixtures with growth regulators on potato tuber nutritive value as well as iron and manganese contents and uptake with the yield of potato tubers. Iron and manganese contents of tubers and uptake with tuber yield were significantly affected by cultivars, herbicides and biostimulants applied as well as weather conditions during the growing season. The herbicides and biostimulants increased iron and manganese contents and uptake with the yield of potato tubers compared with control tubers. The highest amounts of the examined microelements were accumulated by cv. Honorata compared with cv. Bartek and Gawin. Consumption of 100 g potato tubers in 9 and 21% satisfied the daily requirement for iron and manganese, the daily requirements in the human diet being 14.0 and 2.0 mg, respectively.

Callery pear (Pyrus calleryana) Response to Fire in a Managed Prairie Ecosystem

AbstractCallery pear (Pyrus calleryana Decne.) was introduced to North America as an ornamental tree in the early 1900s. Due to widespread planting, P. calleryana has become common throughout the eastern United States and has invaded natural areas, especially disturbed areas. Prescribed fire is a common management technique in prairie ecosystems to mimic natural disturbances. We tested the effectiveness of prescribed fire as a control technique for P. calleryana in a managed prairie system. Fire top-killed all established P. calleryana individuals. However, these individuals responded to fire with 3 to 4 epicormic sprouts each. Similar sprouting behavior occurred in 2-yr-old seedlings. Exposed seeds, fruits, and 1-yr-old seedlings were killed by fire. Established P. calleryana were single-stemmed individuals before exposure to fire. After the prescribed fire, they all were multistemmed, which increased the potential flower-bearing stems within the prairie. We conclude that fire alone is not a suitable technique for managing P. calleryana invasion. Cut and herbicide application methods are labor-intensive. However, combining cut and spray methods with prescribed fire may be effective. Fire removes standing grass and forb biomass, leaving exposed P. calleryana stems, which would make locating individuals and directly applying herbicides easier.