A model for predicting invasive weed and grass dynamics. I. Model development

Weed Science ◽  
2005 ◽  
Vol 53 (5) ◽  
pp. 586-593 ◽  
Author(s):  
Matthew J. Rinella ◽  
Roger L. Sheley

Invasive weed managers are presented with a complicated and ever-enlarging set of management alternatives. Identifying the optimal weed management strategy for a given set of conditions requires predicting how candidate strategies will affect plant community composition. Although field experiments have advanced our ability to predict postmanagement composition, extrapolation problems limit the prediction accuracy achieved by interpreting treatment means as predictions. Examples of extrapolation problems include nonlinear relationships between competing plants, site-to-site variation in plant population growth rates, and the carrying capacities of desired species and weeds. Our objective was to develop a model that improves predictions of weed management outcomes by overcoming a subset of these problems. To develop the model, we used data from two field experiments in which four Kentucky bluegrass, six western wheatgrass, and six invasive plant (i.e., leafy spurge) densities were combined in field plots. Graphs of our model's predictions vs. observed field experiment data indicate that the model predicted the data accurately. Our model may improve predictions of plant community response to invasive weed management actions.

Weed Science ◽  
2005 ◽  
Vol 53 (5) ◽  
pp. 605-614 ◽  
Author(s):  
Matthew J. Rinella ◽  
Roger L. Sheley

The impact of invasive weed management on plant community composition is highly dependent on location-specific factors. Therefore, treatment means from experiments conducted at a given set of locations will not reliably predict community response to weed management elsewhere. We developed a model that rescales treatment means to better match local conditions. The goal of this paper was to determine if this rescaling improves predictions. We used our model to predict leafy spurge stem length density and grass biomass data from field experiments. The experiments consisted of herbicide-treated plots, untreated controls, and, in some cases, grass seeding treatments. When herbicides suppressed leafy spurge, the model explained 21 to 48% more variation in grass response than did mean grass response to the same or similar herbicide treatments applied at other sites. When herbicides killed grass, the model explained 53% more variation in leafy spurge response than did mean leafy spurge response to the same herbicide treatment applied at other sites. We regressed model predictions against observed data and tested the null hypothesis that resulting slope terms were equal to 1.0. Because the null hypothesis was rejected in two of four tests, the model may systematically over- or underpredict in some situations. However, measurement error in the observed data, unintended herbicide injury, or an inaccurate allometric relationship may account for a major proportion of the systematic deviations, and these factors would not cause prediction error in some management applications. Because the model tends to be better than the means from experiments at predicting plant community composition, we conclude that the model could advance managers' ability to predict plant community responses to invasive weed management.


2013 ◽  
Vol 6 (1) ◽  
pp. 48-59 ◽  
Author(s):  
Leonardo Frid ◽  
David Hanna ◽  
Nathan Korb ◽  
Brad Bauer ◽  
Katherine Bryan ◽  
...  

AbstractDetermining the best strategy for allocating weed management resources across and between landscapes is challenging because of the uncertainties and large temporal and spatial scales involved. Ecological models of invasive plant spread and control provide a practical tool with which to evaluate alternative management strategies at landscape scales. We developed a spatially explicit model for the spread and control of spotted knapweed and leafy spurge across three Montana landscapes. The objective of the model was to determine the ecological and economic costs and benefits of alternative strategies across landscapes of varying size and stages of infestation. Our results indicate that (1) in the absence of management the area infested will continue to increase exponentially leading to a substantial cost in foregone grazing revenues; (2) even though the costs of management actions are substantial, there is a net economic benefit associated with a broad range of management strategies; (3) strategies a that prioritize targeting small new infestations consistently outperform strategies that target large established patches; and (4) inconsistent treatment and short-term delays can greatly reduce the economic and ecological benefits of management.


2012 ◽  
Vol 5 (2) ◽  
pp. 300-309 ◽  
Author(s):  
Corey V. Ransom ◽  
Stephanie D. Christensen ◽  
Kimberly A. Edvarchuk ◽  
Tamara Naumann

AbstractInvasive weed management in wildland areas is often challenging due to the need to protect and preserve the integrity of natural ecosystems. Russian knapweed is an aggressive, deep-rooted, creeping perennial forb that was first identified as a problematic species in Dinosaur National Monument in 1977. From 2002 to 2005, extensive nonnative plant inventories were conducted in portions of the monument. Results were used to develop and implement an aggressive weed management program beginning in 2005. Emphasis was placed on reducing Russian knapweed infestations around Josie's Ranch in the Cub Creek Watershed. Several other species were targeted as well. In 2010, a reinventory was conducted in selected areas to evaluate how implemented management strategies affected the overall distribution and abundance of targeted species on the landscape. Comparisons between inventories indicate that management strategies were successful in reducing the total infested area of Russian knapweed by 79%. Treatments used for other targeted species also appear to have been effective in reducing their overall distribution and abundance on the landscape. In addition, the reinventory identified several new species with the potential to become problematic in the area. Although this case study documents the substantial progress that has been made at Dinosaur National Monument toward obtaining specific weed management objectives, it more importantly illustrates the process and benefits of an adaptive approach in sustaining long-term invasive plant species management efforts.


2008 ◽  
Vol 1 (1) ◽  
pp. 66-72 ◽  
Author(s):  
Carl E. Bell ◽  
Todd Easley ◽  
Kari Roesch Goodman

AbstractFennel is a major invasive plant in many lower elevation natural areas in coastal California. Three identical field experiments were conducted to evaluate glyphosate and triclopyr for control of fennel. Treatments included each herbicide applied alone and in various combinations. We also compared broadcast applications to spot spraying of individual fennel plants because spot spraying is a commonly used technique in natural area weed management. Most treatments controlled fennel well when evaluated 6 wk and 1 yr after treatment, with the exception of the lowest rate of glyphosate. Purple needlegrass, a native perennial grass, was present in two of the sites. In most, but not all, treatment and site combinations, it was not significantly harmed by the herbicides. The spot spray applications were less effective and used more herbicide per unit area than the broadcast spraying.


2017 ◽  
Vol 6 (05) ◽  
pp. 1614 ◽  
Author(s):  
Ramesh B.N. ◽  
Sunil Kumar R. ◽  
Pramod R. ◽  
Jayaramiah R.

Parthenium hysterophorus is commonly known as congress grass or carrot weed in India. It belongs to Asteraceae family and native to subtropics of North and South America. It is an invasive plant species that disturbs cultivated areas, roadside vegetation, gardens etc. P. hysterophorus is considered as one of the worst weeds responsible for causing health problems in animals and humans viz., dermatitis, asthma and bronchitis besides loss to agriculture and ecosystem. Nowadays, it has become one of the major weeds in almost all types of agricultural lands and other areas. Many control methods ranging from preventive, physical methods by manual uprooting, burning and allelopathic management through competitive plants like Cassia tora, Cassia uniflora Cassia sericea, have been recommended for management of P. hysterophorus. Likewise, insect Zygogramma bicolorata has proven successful in managing  P. hysterophorus. Further, microorganisms like Alternaria alternata, Scerotiia sclerotiorum, Fusarium Pallidoroseum, Ralstonia solanacearum, Xanthomanas campestris are reported to infest P. hysterophorus. Use of chemical herbicides mainly glyphosate @ 2.5 kg a.i.ha-1,atrazine @ 2.6 kg a.i.ha-1,2,4-D amine @ 3 l/ ha-1, Paraquat 0.5 l/ ha-1 were proved effective in managing P. hysterophorus. No single option is suitable to control this invasive weed. Successful control of this weed can only be achieved by an integrated weed management approaches.


2018 ◽  
Vol 11 (3) ◽  
pp. 127-135 ◽  
Author(s):  
Cara Applestein ◽  
Matthew J. Germino ◽  
Matthew R. Fisk

AbstractDisturbances such as wildfire create time-sensitive windows of opportunity for invasive plant treatment, and the timing of herbicide application relative to the time course of plant community development following fire can strongly influence herbicide effectiveness. We evaluated the effect of herbicide (imazapic) applied in the first winter or second fall after the 113,000 ha Soda wildfire on the target exotic annual grasses and also key non-target components of the plant community. We measured responses of exotic and native species cover, species diversity, and occurrence frequency of shrubs and forbs seeded before (1 to 2 or 9 to 10 mo) herbicide application. Additionally, we asked whether landscape factors, including topography, species richness, and/or soil characteristics, influenced the effectiveness of imazapic. Cover of exotic annual grass cover, but not of deep-rooted perennial bunchgrass, was less where imazapic had been applied, whereas more variability was evident in the response of Sandberg bluegrass (Poa secunda J. Presl) and seeded shrubs and forbs. Regression-tree analysis of the subset of plots measured both before and after the second fall application revealed greater reductions of exotic annual grass cover in places where their cover was <42% before spraying. Otherwise, imazapic effects did not vary with the landscape factors we analyzed.


2020 ◽  
Vol 57 (3) ◽  
pp. 199-210
Author(s):  
Rajib Kundu ◽  
Mousumi Mondal ◽  
Sourav Garai ◽  
Ramyajit Mondal ◽  
Ratneswar Poddar

Field experiments were conducted at research farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, West Bengal, India (22°97' N latitude and 88°44' E longitude, 9.75 m above mean sea level) under natural weed infestations in boro season rice (nursery bed as well as main field) during 2017-18 and 2018-19 to evaluate the herbicidal effects on weed floras, yield, non-target soil organisms to optimize the herbicide use for sustainable rice-production. Seven weed control treatments including three doses of bispyribac-sodium 10% SC (150,200, and 250 ml ha-1), two doses of fenoxaprop-p-ethyl 9.3% EC (500 and 625 ml ha-1), one weed free and weedy check were laid out in a randomized complete block design, replicated thrice. Among the tested herbicides, bispyribac-sodium with its highest dose (250 ml ha-1) resulted in maximum weed control efficiency, treatment efficiency index and crop resistance index irrespective of weed species and dates of observation in both nursery as well as main field. Similar treatment also revealed maximum grain yield (5.20 t ha-1), which was 38.38% higher than control, closely followed by Fenoxaprop-p-ethyl (625 ml ha-1) had high efficacy against grasses, sedge and broadleaf weed flora. Maximum net return (Rs. 48765 ha-1) and benefit cost ratio (1.72) were obtained from the treatment which received bispyribac-sodium @ 250 ml ha-1. Based on overall performance, the bispyribac-sodium (250 ml ha-1) may be considered as the best herbicide treatment for weed management in transplanted rice as well as nursery bed.


2021 ◽  
pp. 1-39
Author(s):  
Nathan H. Haugrud ◽  
Thomas J. Peters

Abstract The invasion of waterhemp into northern sugarbeet growing regions has prompted producers to re-integrate inter-row cultivation into weed management programs as no currently registered herbicides can control glyphosate-resistant waterhemp POST in crop. Inter-row cultivation was a common weed control practice in sugarbeet until the release of glyphosate-resistant sugarbeet cultivars in 2008 made the use of inter-row cultivation unnecessary. In the late 2010s, producers began again to use inter-row cultivation to remove weeds that glyphosate did not control, but producers need information on the effectiveness and safety of inter-row cultivation when used with soil residual herbicide programs. Efficacy and tolerance field experiments were conducted in Minnesota and North Dakota from 2017 to 2019. Results from the efficacy experiment demonstrated cultivation improved waterhemp control 11% and 12%, 14 and 28 DAT, respectively. Waterhemp response to cultivation was dependent on crop canopy and precipitation after cultivation. Cultivation had minimal effect on waterhemp density in three environments, but at one environment, near Galchutt, ND in 2019, waterhemp density increased 600% and 196%, 14 and 28 DAT, respectively. Climate data indicated Galchutt, ND in 2019 received 105 mm of precipitation in the 14 days following cultivation and had an open crop canopy which likely contributed to further weed emergence. Results from the tolerance experiment demonstrated root yield and recoverable sucrose were not affected by cultivation timing or number of cultivations. In one environment, cultivating reduced sucrose content by 0.8% regardless of date or cultivation number, but no differences were found in three environments. In-season cultivation can damage/destroy leaf tissue which is likely responsible for the reduction in sucrose content. Results indicate cultivation can be a valuable tool to control weeds that herbicide cannot, but excessive rainfall and open crop canopy following cultivation can create an environment conducive to further weed emergence.


1970 ◽  
Vol 33 (4) ◽  
pp. 623-629 ◽  
Author(s):  
MSA Khan ◽  
MA Hossain ◽  
M Nurul Islam ◽  
SN Mahfuza ◽  
MK Uddin

Field experiments were conducted at the research farm of Bangladesh Agricultural Research Institute, Joydebpur during kharif-1 (March to July) seasons of 2005 and 2006 to identify the critical period of crop-weed competition for Indian spinach. Major weed species were Paspalurn commersoni, Echinochlaa crusgalli. Lie nv/nc india. Cyanotis axillaris and Cyperus rotundus. The lowest weed dry matter was 76.3 g m-2 in 2005 and l01.60 g m-2 in 2006 from the plots weeded up to 40 days after transplanting (DAT). The highest yields were obtained (74.82 t ha in 2005 and 48.48 t ha in 2006) from the weed free plots. The fresh yield of Indian spinach did not vary among no weeding upto 20, 30 and 40 DAT in 2006. But weeded plot upto 30 and 40 DAT produced identical yield in 2005. Maximum BCR (4.52) was obtained from weeded plots upto 30 DAT in 2005 but BCR (2.60) was same from weeded upto 30 and 40 DA F in 2006. On an average, highest BCR (3.55) was recorded from weeding upto 30 DAT. Results revealed that the critical period of crop weed competition lies between 20 and 30 DAT and two times hand weeding would be necessary within 30 DAT for maximum benefit. Key Words: Crop-weed competitions, critical period, weed management and Indian spinach. doi: 10.3329/bjar.v33i4.2306 Bangladesh J. Agril. Res. 33(4) : 623-629, December 2008


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