scholarly journals Whole-Plant and Seed Bioassays for Resistance Confirmation

Weed Science ◽  
2015 ◽  
Vol 63 (SP1) ◽  
pp. 152-165 ◽  
Author(s):  
Nilda R. Burgos
Keyword(s):  
Best Management Practices ◽  
Crop Production ◽  
Management Practices ◽  
List Type ◽  
Plant Parts ◽  
Resistance Evolution ◽  
Whole Plant ◽  
Weedy Species ◽  
Whole Plants ◽  
Sites Of Action

Much of agriculture-related research today involves weed resistance to herbicides. Resistance evolution is perhaps the strongest driver for the quest for new herbicide targets, novel weed intervention technologies, and the promotion of best management practices for sustainable crop production (Burgos et al., 2006; Norsworthy et al. 2012; Vencill et al. 2012). To date, 222 weedy species collectively have evolved resistance to 150 herbicides representing 21 sites of action (Heap 2014). For decades, scientists have developed numerous protocols for resistance confirmation using seeds, different plant parts, or whole plants. These have been reviewed by Beckie et al. (2000) and Burgos et al. (2013). We draw from these and other sources to present general guidelines for resistance confirmation that students and new researchers can use in planning their experiments. The most immediate questions that stakeholders seek to answer with resistance bioassays include:1.Is the population resistant?2.What is the level of resistance?3.What alternative herbicides can be used?

Confirmation of Glyphosate-Resistant Horseweed (Conyza canadensis) in Montana Cereal Production and Response to POST Herbicides

2017 ◽  
Vol 31 (6) ◽  
pp. 799-810 ◽  
Author(s):  
Vipan Kumar ◽  
Prashant Jha ◽  
Amit J. Jhala
Keyword(s):  
Great Plains ◽  
Dose Response ◽  
Best Management Practices ◽  
Management Practices ◽  
Dry Weight ◽  
Shoot Dry Weight ◽  
Greenhouse Study ◽  
Whole Plant ◽  
Cereal Production ◽  
Sites Of Action

In recent years, horseweed has become an increasing problem in Montana. To confirm and characterize the level of glyphosate resistance, seeds were collected from putative glyphosate-resistant (GR) horseweed (GR-MT) plants in a wheat–fallow field in McCone County, MT. Known GR (GR-NE) and glyphosate-susceptible (GS-NE) horseweed accessions from Lincoln, NE, were included for comparison in dose–response and shikimate accumulation studies. Whole-plant glyphosate dose–response experiments conducted at the early- (5- to 8-cm diameter) and late- (12- to 15-cm diameter) rosette stages of horseweed indicated that GR-MT accessions had a 2.5- to 4.0-fold level of resistance to glyphosate relative to the GS-NE accession, on the basis of shoot dry weight (GR50values). The level of resistance was 3.1- to 7.9-fold on the basis of visually assessed injury estimates (I50values). At the whole-plant level, about 2.1- to 4.5-fold higher shikimate accumulation was observed in the GS-NE accession compared with the GR-MT and GR-NE accessions over a 10-d period after glyphosate was applied at 1,260 g ae ha−1. In a separate greenhouse study, all three horseweed accessions were also screened with alternate POST herbicides registered for use in wheat–fallow rotations. The majority of the tested herbicides provided ≥90% injury at the field-use rates for all three horseweed accessions 3 wk after treatment. This is the first published report on the occurrence of GR horseweed in Montana cereal production. Increased awareness and adoption of best management practices, including the use of diversified (based on multiple sites of action) herbicide programs highlighted in this study, would aid in mitigating the further spread of GR horseweed in the cereal production fields of the U.S. Great Plains.

Field Measurements and Simulation of Nitrogen Fate under Citrus Production

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 498c-498
Author(s):  
A. Fares ◽  
A.K. Alva ◽  
S. Paramasivam
Keyword(s):  
Mass Balance ◽  
Best Management Practices ◽  
Rainy Season ◽  
Crop Production ◽  
Management Practices ◽  
Root Zone ◽  
Field Measurements ◽  
Irrigation Scheduling ◽  
N Leaching ◽  
Citrus Production

Water and nitrogen (N) are important inputs for most crop production. The main objectives of nitrogen best management practices (NBMP) are to improve N and water management to maximize the uptake efficiency and minimize the leaching losses. This require a complete understanding of fate of N and water mass balance within and below the root zone of the crop in question. The fate of nitrogen applied for citrus production in sandy soils (>95% sand) was simulated using a mathematical model LEACHM (Leaching Estimation And Chemistry Model). Nitrogen removal in harvested fruits and storage in the tree accounted the major portion of the applied N. Nitrogen volatilization mainly as ammonia and N leaching below the root zone were the next two major components of the N mass balance. A proper irrigation scheduling based on continuous monitoring of the soil water content in the rooting was used as a part of the NBMP. More than 50% of the total annual leached water below the root zone was predicted to occur in the the rainy season. Since this would contribute to nitrate leaching, it is recomended to avoid N application during the rainy season.

scholarly journals Prioritization of Sub-Watersheds to Sediment Yield and Evaluation of Best Management Practices in Highland Ethiopia, Finchaa Catchment

Land ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 650
Author(s):  
Wakjira Takala Dibaba ◽  
Tamene Adugna Demissie ◽  
Konrad Miegel
Keyword(s):  
Soil Erosion ◽  
Best Management Practices ◽  
Sediment Yield ◽  
Soil Loss ◽  
Crop Production ◽  
Management Practices ◽  
Assessment Tool ◽  
Swat Model ◽  
Sediment Yields ◽  
Soil And Water

Excessive soil loss and sediment yield in the highlands of Ethiopia are the primary factors that accelerate the decline of land productivity, water resources, operation and function of existing water infrastructure, as well as soil and water management practices. This study was conducted at Finchaa catchment in the Upper Blue Nile basin of Ethiopia to estimate the rate of soil erosion and sediment loss and prioritize the most sensitive sub-watersheds using the Soil and Water Assessment Tool (SWAT) model. The SWAT model was calibrated and validated using the observed streamflow and sediment data. The average annual sediment yield (SY) in Finchaa catchment for the period 1990–2015 was 36.47 ton ha−1 yr−1 with the annual yield varying from negligible to about 107.2 ton ha−1 yr−1. Five sub-basins which account for about 24.83% of the area were predicted to suffer severely from soil erosion risks, with SY in excess of 50 ton ha−1 yr−1. Only 15.05% of the area within the tolerable rate of loss (below 11 ton ha−1yr−1) was considered as the least prioritized areas for maintenance of crop production. Despite the reasonable reduction of sediment yields by the management scenarios, the reduction by contour farming, slope terracing, zero free grazing and reforestation were still above the tolerable soil loss. Vegetative contour strips and soil bund were significant in reducing SY below the tolerable soil loss, which is equivalent to 63.9% and 64.8% reduction, respectively. In general, effective and sustainable soil erosion management requires not only prioritizations of the erosion hotspots but also prioritizations of the most effective management practices. We believe that the results provided new and updated insights that enable a proactive approach to preserve the soil and reduce land degradation risks that could allow resource regeneration.

scholarly journals Innovative Extension Methods in the U.S. to Promote Irrigation Water Management

2020 ◽  
Vol 63 (5) ◽  
pp. 1549-1558
Author(s):  
Daran R. Rudnick ◽  
Matt Stockton ◽  
Saleh Taghvaeian ◽  
Jason Warren ◽  
Michael D. Dukes ◽  
...  
Keyword(s):  
Water Management ◽  
Experiential Learning ◽  
Best Management Practices ◽  
Irrigation Water ◽  
Management Practices ◽  
New Technology ◽  
List Type ◽  
Extension Programs ◽  
Irrigation Water Management ◽  
Primary Means

HIGHLIGHTSUniversity extension has been playing a larger role, serving a larger number of irrigated farms.Extension programs in irrigation water management (IWM) have been transitioning away from lectures and field tours as the primary means of knowledge transfer.New IWM programs focus on experiential learning, development of practitioner networks, and industry participation.Abstract. Promotion and adoption of irrigation water management (IWM) technology, tools, and best management practices are important as water availability concerns are addressed. Traditional extension programs have relied on lecture presentations, field tours, fact sheets, and on-station demonstrations to promote IWM practices and tools. However, these platforms tend not to provide the experience and opportunity for growers to identify and become comfortable with innovative solutions, such as new technology. To address these challenges and to appeal to an ever-changing client base, innovative and locally relevant extension and outreach programs have been devised to engage and educate growers. This article describes some of these programs that extend beyond previous traditional programs to connect growers with IWM. Keywords: Demonstrations, Experiential learning, Grower competition, Outreach, Practitioner networks.

scholarly journals Rewarding Best Pest Management Practices via Reduced Crop Insurance Premiums

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Hugh J. Beckie ◽  
Stuart J. Smyth ◽  
Micheal D. K. Owen ◽  
Savannah Gleim
Keyword(s):  
Pest Management ◽  
Best Management Practices ◽  
Financial Incentives ◽  
Management Practices ◽  
Crop Insurance ◽  
The United States ◽  
Best Management ◽  
Policy Objectives ◽  
Sites Of Action ◽  
Industry Sectors

Despite decades of research, development, and extension on the mitigation and management of pesticide resistance, the global agricultural situation is becoming increasingly dire. Pest populations with evolved resistance to multiple pesticide sites of action are becoming the norm, with fewer remaining effective xenobiotics for control. We argue that financial incentives and not regulations are needed to encourage farmers or land managers to use best management practices recommended by academia. Although some incentives are offered by pesticide manufacturers or distributors, there is a paucity of incentives by other industry sectors and all levels of government (federal or state/provincial). Crop insurance can be important to facilitate and reward best pest management practices and address other important agricultural policy objectives. Herein, we describe possible changes to crop insurance programs in the United States and Canada through premium rate changes to incentivise clients to adopt best management practices.

scholarly journals Risk Assessment of Glyphosate Resistance in Western Canada

2011 ◽  
Vol 25 (1) ◽  
pp. 159-164 ◽  
Author(s):  
Hugh J. Beckie ◽  
K. Neil Harker ◽  
Linda M. Hall ◽  
Frederick A. Holm ◽  
Robert H. Gulden
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Cropping Systems ◽  
Resistance Management ◽  
Decision Support Tool ◽  
Glyphosate Resistance ◽  
Western Canada ◽  
Support Tool ◽  
Resistance Evolution ◽  
Risk Rating

With increasing incidence of glyphosate-resistant weeds worldwide, greater farmer awareness of the importance of glyphosate stewardship and proactive glyphosate-resistance management is needed. A Web-based decision-support tool (http://www.weedtool.com) comprising 10 questions has been developed primarily for farmers in western Canada to assess the relative risk of selection for glyphosate-resistant weeds on a field-by-field basis. We describe the rationale for the questions and how a response to a particular question influences the risk rating. Practices with the greatest risk weighting in western Canadian cropping systems are lack of crop-rotation diversity (growing mainly oilseeds) and a high frequency of glyphosate-resistant crops in the rotation. Three case scenarios are outlined—low, moderate, and high risk of glyphosate-resistance evolution. Based on the overall risk rating, three best-management practices are recommended to reduce the risk of glyphosate resistance in weeds.

scholarly journals Carbon footprint of lentil in old Brahmaputra floodplain soil

2016 ◽  
Vol 27 (2) ◽  
pp. 162-167
Author(s):  
ME Haq ◽  
MA Kader ◽  
S Farhan
Keyword(s):  
Carbon Footprint ◽  
Best Management Practices ◽  
Food Production ◽  
Crop Production ◽  
Management Practices ◽  
Ghg Emissions ◽  
Production Capacity ◽  
Low Carbon ◽  
Floodplain Soil ◽  
Science Field

Crop production has contributed significantly to global carbon footprint (CF). Characterizing the carbon footprint of agricultural production offers key information for achieving low carbon agriculture. Bangladesh has struggled for long and worked hard for increasing food production capacity for its large growing population. It is necessary to choose the crops and management practices which have low CF to maintain a win-win situation between food production and greenhouse gas (GHG) emissions. However, the CF of Bangladesh’s crop production has not yet been assessed. Therefore, this study was conducted to estimate the CF of lentil as one of the major legumes cultivated in Bangladesh. The crop was cultivated at the Soil Science Field Laboratory of Bangladesh Agricultural University (BAU) Farm, Mymensingh i.e. Agro-ecological zone (AEZ 9) during November, 2013 to April, 2014 by following standard management practices. The Carbon footprint was calculated by using the collected emission factors from literature as default values for each input and operation used for the production of crops as per guideline of ISO (2006) and IPCC (2006). The GHG emissions in the crop fields are taken from the studies of Pathak and Aggarwal (2012). The yield of lentil was 0.90 t ha-1 with a CF of 406 kg CO2-equivalentst-1 of lentil. Direct and indirect GHG emissions singly contributed the half of CF accounting 52.54% of total CF. The contribution of fertilizer, irrigation, machinery and labor inputs to the overall carbon footprint were 23.16%, 15.97%, 1.26% and 7.06%, respectively. Among the fertilizers, nitrogenous fertilizer was dominant and singly contributed to 70% of fertilizer CF. However, for developing best management practices for climate change mitigation in crop production of Bangladesh, further studies of soil and regional specific CFs of lentil are needed.Progressive Agriculture 27 (2): 162-167, 2016

DRAINMOD-P: A Model for Simulating Phosphorus Dynamics and Transport in Drained Agricultural Lands: I. Model Development

2021 ◽  
Vol 64 (6) ◽  
pp. 1835-1848
Author(s):  
Manal H. Askar ◽  
Mohamed A. Youssef ◽  
Peter A. Vadas ◽  
Dean L. Hesterberg ◽  
Aziz Amoozegar ◽  
...  
Keyword(s):  
Water Quality ◽  
Soil Erosion ◽  
Best Management Practices ◽  
Management Practices ◽  
Subsurface Drainage ◽  
Water Quality Modeling ◽  
List Type ◽  
Macropore Flow ◽  
Drainage Systems ◽  
P Cycling

HighlightsDRAINMOD-P has been developed to simulate phosphorus (P) dynamics in drained croplands.Key hydrological and biochemical processes affecting P cycling are represented in the model.The model predicts surface and subsurface P losses as affected by weather, soil, and management factors.Abstract. High phosphorus (P) loads to streams and lakes can promote harmful algae blooms and cause water quality deterioration. Recent research has identified subsurface drainage as an important pathway for the transport of dissolved P from drained croplands to receiving surface water bodies, particularly when macropore flow contributes a considerable portion of the subsurface drainage outflow. Currently, a few models are capable of simulating P dynamics in poorly drained soils with artificial drainage systems. The objective of this study was to develop DRAINMOD-P, a field-scale, process-based model that simulates P cycling and transport in drained croplands. Processes represented in the model include atmospheric deposition, organic and inorganic fertilizer applications, plant uptake, sediment-bound and dissolved P losses in both surface runoff and subsurface drainage, tillage practices, and P mineralization and immobilization. The model predicts P losses under different management practices, climatic conditions, drainage systems, and crop rotations. The model is an extension to the nitrogen model DRAINMOD-NII, with full integration of the nitrogen and P model components. DRAINMOD-P uses the recently modified hydrology component that simulates macropore flow. A soil erosion component, based on the RUSLE approach, has been incorporated into the model to estimate sediment loss and associated particulate P loss. Sediment deposition in tile drains is considered to quantify particulate P settling in the drainage system. In this article, we review the approaches used in DRAINMOD-P for simulating P-related processes. Model testing against field-measured data from a subsurface-drained field in northwest Ohio is presented in a companion article. Keywords: Best management practices, Phosphorus model, Phosphorus processes, Soil erosion, Water quality modeling.

scholarly journals Reducing the Risks of Herbicide Resistance: Best Management Practices and Recommendations

Weed Science ◽  
2012 ◽  
Vol 60 (SP1) ◽  
pp. 31-62 ◽  
Author(s):  
Jason K. Norsworthy ◽  
Sarah M. Ward ◽  
David R. Shaw ◽  
Rick S. Llewellyn ◽  
Robert L. Nichols ◽  
...  
Keyword(s):  
Weed Control ◽  
Herbicide Resistance ◽  
Best Management Practices ◽  
Weed Management ◽  
Crop Production ◽  
Management Practices ◽  
Production Systems ◽  
Herbicide Resistant ◽  
Economic Thresholds ◽  
Soil Seedbank

Herbicides are the foundation of weed control in commercial crop-production systems. However, herbicide-resistant (HR) weed populations are evolving rapidly as a natural response to selection pressure imposed by modern agricultural management activities. Mitigating the evolution of herbicide resistance depends on reducing selection through diversification of weed control techniques, minimizing the spread of resistance genes and genotypes via pollen or propagule dispersal, and eliminating additions of weed seed to the soil seedbank. Effective deployment of such a multifaceted approach will require shifting from the current concept of basing weed management on single-year economic thresholds.

Phloem mobility of crop protection products

2000 ◽  
Vol 27 (6) ◽  
pp. 609 ◽  
Author(s):  
Frank Lichtner
Keyword(s):  
Growth And Development ◽  
Crop Production ◽  
Crop Protection ◽  
Chemical Properties ◽  
Dietary Exposure ◽  
Small Molecular Weight ◽  
Macromolecular Transport ◽  
Plant Parts ◽  
Whole Plants ◽  
Phloem Mobility

Phloem mobility of a crop protectant is an attribute that contributes positively to its efficacy. Herbicides, insecticides and fungicides, generally organic molecules of small molecular weight, are applied foliarly and often must move to remote plant parts (such as meristems, emerging leaves, roots and fruits) via the phloem to achieve economically useful activity. In addition, insecticides must move within the phloem to be effective against piercing and sucking insects. Conversely, phloem mobility of crop protectants and their metabolites can also contribute to detectable residues in raw agricultural commodities. This is especially true of compounds that are biologically stable and applied during fruit development or seed set. Thus, the knowledge of phloem mobility allows an understanding of potential benefits (efficacy) and potential risks (dietary exposure) of a crop protection chemical. The customers for this knowledge range from the discovery chemist and biologist (who participate in the design of the chemical), through to the regulatory official (who grants permission to sell) and the farmer, the ultimate beneficiary of the technology. One can estimate or predict phloem mobility (based on physical/chemical properties and molecular structure) using a number of models, or measure it directly (in whole plants or explants) with a variety of techniques. In the future, crop protection and crop production technology will increasingly rely on effective transport of macro-molecules, such as protein toxins for insect control and mRNA for signal initiation and coordination of growth and development processes. Phloem mobility will be equally important for these macromolecules and for the small molecules that currently control pests and influence plant growth and development. Understanding the processes that control macromolecular transport in the phloem will lay the foundation for effective use of this technology in the decades to come.

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