Detection of pitted morningglory (Ipomoea lacunosa) by hyperspectral remote sensing. I. Effects of tillage and cover crop residue

Weed Science ◽  
2004 ◽  
Vol 52 (2) ◽  
pp. 222-229 ◽  
Author(s):  
Clifford H. Koger ◽  
David R. Shaw ◽  
Krishna N. Reddy ◽  
Lori M. Bruce
Keyword(s):  
Cover Crop ◽  
Crop Residue ◽  
Field Experiments ◽  
Leaf Growth ◽  
Plant Size ◽  
Hyperspectral Reflectance ◽  
Discrimination Accuracy ◽  
Reflectance Measurement ◽  
Pitted Morningglory ◽  
Residue Systems

Field experiments were conducted to evaluate the potential of hyperspectral reflectance data collected with a hand-held spectroradiometer to discriminate soybean intermixed with pitted morningglory and weed-free soybean in conventional till and no-till plots containing rye, hairy vetch, or no cover crop residue. Pitted morningglory was in the cotyledon to six-leaf growth stage. Seven 50-nm spectral bands (one ultraviolet, two visible, four near-infrared) derived from each hyperspectral reflectance measurement were used as discrimination variables. Pitted morningglory plant size had more influence on discriminant capabilities than tillage or cover crop residue systems. Across all tillage and residue systems, discrimination accuracy was 71 to 95%, depending on the size of pitted morningglory plants at the time of data acquisition. The versatility of the seven 50-nm bands was tested by using a discriminant model developed for one experiment location to test discriminant capabilities for the other experiment, with discrimination accuracy across all tillage and residue systems of 55 to 73%, depending on pitted morningglory plant size.

Detection of pitted morningglory (Ipomoea lacunosa) with hyperspectral remote sensing. II. Effects of vegetation ground cover and reflectance properties

Weed Science ◽  
2004 ◽  
Vol 52 (2) ◽  
pp. 230-235 ◽  
Author(s):  
Clifford H. Koger ◽  
David R. Shaw ◽  
Krishna N. Reddy ◽  
Lori M. Bruce
Keyword(s):  
Remote Sensing ◽  
Near Infrared ◽  
Leaf Growth ◽  
Ground Cover ◽  
Hyperspectral Remote Sensing ◽  
Hyperspectral Data ◽  
Growth Stages ◽  
Discrimination Accuracy ◽  
Reflectance Measurement ◽  
Pitted Morningglory

Field research was conducted to determine the potential of hyperspectral remote sensing for discriminating plots of soybean intermixed with pitted morningglory and weed-free soybean with similar and different proportions of vegetation ground cover. Hyperspectral data were collected using a handheld spectroradiometer when pitted morningglory was in the cotyledon to two-leaf, two- to four-leaf, and four- to six-leaf growth stages. Synthesized reflectance measurements containing equal and unequal proportions of reflectance from vegetation were obtained, and seven 50-nm spectral bands (one ultraviolet, two visible, and four near-infrared) derived from each hyperspectral reflectance measurement were used as discrimination variables to differentiate weed-free soybean and soybean intermixed with pitted morningglory. Discrimination accuracy was 93 to 100% regardless of pitted morningglory growth stage and whether equal or unequal proportions of reflectance from vegetation existed in weed-free soybean and soybean intermixed with pitted morningglory. Discrimination accuracy was 88 to 98% when using the discriminant model developed for one experiment to discriminate soybean intermixed with pitted morningglory and weed-free soybean plots of the other experiment. Reflectance in the near-infrared spectrum was higher for weed-free soybean compared with soybean intermixed with pitted morningglory, and this difference affected the ability to discriminate weed-free soybean from soybean intermixed with pitted morningglory.

scholarly journals Spatial and temporal variability in Powell amaranth (Amaranthus powellii) emergence under strip tillage with cover crop residue

Weed Science ◽  
2016 ◽  
Vol 65 (1) ◽  
pp. 151-163 ◽  
Author(s):  
Erin R. Haramoto ◽  
Daniel C. Brainard
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Crop Residue ◽  
Field Experiments ◽  
Abiotic Factors ◽  
Planting Date ◽  
Spatial And Temporal Variability ◽  
Natural Rainfall ◽  
Strip Tillage ◽  
The Impact

The objectives of this research were to evaluate temporal and spatial variability in the impact of strip tillage and oat cover crop residue on Powell amaranth emergence and to determine the role of rainfall in mediating these effects. In field experiments conducted in 2010, 2011, and 2012, Powell amaranth seeds were sown in a fully factorial combination of two tillage types (strip tillage [ST] vs. full-width tillage [FWT]) and cover crop residue (oats vs. none) at either 0 d after tillage (DAT) or 7 to 13 DAT to monitor emergence at two timings. In ST plots, seeds were sown both in the tilled zone (“in-row,” IR), and between these tilled zones (“between-row,” BR). In 2011 and 2012, three levels of rainfall were simulated in subplots by either excluding rainfall, allowing natural rainfall, or supplementing rainfall with irrigation. In most cases, ST and oats residue either had no effect on or suppressed emergence of Powell amaranth sown at the early planting date. In contrast, the emergence response to ST and residue at the later planting date was generally smaller and more variable, with increases in emergence observed in several cases. Differences between tillage systems in emergence were most pronounced in the BR zone but also occurred IR in some cases, suggesting that interzonal effects on biotic or abiotic factors influenced emergence. Oat residue effects—but rarely tillage effects—were often mediated by simulated rainfall, with increases in emergence occurring mostly in dry conditions and decreases occurring more commonly in wetter conditions. These results demonstrate that the suppressive effects of cover crops and ST on weed emergence are inconsistent, temporally and spatially variable, and dependent on complex interactions with factors including rainfall.

Cover Crops Suppression of Palmer Amaranth (Amaranthus palmeri) in Cotton

2017 ◽  
Vol 32 (1) ◽  
pp. 60-65 ◽  
Author(s):  
Matheus G. Palhano ◽  
Jason K. Norsworthy ◽  
Tom Barber
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Field Experiments ◽  
Palmer Amaranth ◽  
Cotton Yield ◽  
Cotton Production ◽  
Seed Cotton ◽  
Cereal Rye ◽  
Seed Cotton Yield ◽  
Weed Emergence

AbstractWith the recent confirmation of protoporphyrinogen oxidase (PPO)-resistant Palmer amaranth in the US South, concern is increasing about the sustainability of weed management in cotton production systems. Cover crops can help to alleviate this problem, as they can suppress weed emergence via allelochemicals and/or a physical residue barrier. Field experiments were conducted in 2014 and 2015 at the Arkansas Agricultural Research and Extension Center to evaluate various cover crops for suppressing weed emergence and protecting cotton yield. In both years, cereal rye and wheat had the highest biomass production, whereas the amount of biomass present in spring did not differ among the remaining cover crops. All cover crops initially diminished Palmer amaranth emergence. However, cereal rye provided the greatest suppression, with 83% less emergence than in no cover crop plots. Physical suppression of Palmer amaranth and other weeds with cereal residues is probably the greatest contributor to reducing weed emergence. Seed cotton yield in the legume and rapeseed cover crop plots were similar when compared with the no cover crop treatment. The seed cotton yield collected from cereal cover crop plots was lower than from other treatments due to decreased cotton stand.

Tillage and Cover Crop Residue Placement Impact Ecosystem Services in Organic Squash

2021 ◽  
Author(s):  
Logan R. Appenfeller ◽  
Daniel C. Brainard ◽  
Zachary D. Hayden ◽  
Marisa M. Benzle ◽  
Michael Metiva ◽  
...  
Keyword(s):  
Ecosystem Services ◽  
Cover Crop ◽  
Crop Residue

Cover crop residue management for optimizing weed control

2008 ◽  
Vol 318 (1-2) ◽  
pp. 169-184 ◽  
Author(s):  
H. Marjolein Kruidhof ◽  
Lammert Bastiaans ◽  
Martin J. Kropff
Keyword(s):  
Weed Control ◽  
Cover Crop ◽  
Crop Residue ◽  
Residue Management ◽  
Crop Residue Management

scholarly journals Plant size, nutrient composition and biomass productivity of oats and faba bean in intercropping, and the effect of controlling Rhopalosiphum padi (Hom., Aphididae) on these properties

1990 ◽  
Vol 62 (1) ◽  
pp. 21-31 ◽  
Author(s):  
Juha Helenius
Keyword(s):  
Faba Bean ◽  
Field Experiments ◽  
Rhopalosiphum Padi ◽  
Relative Yield ◽  
Biomass Productivity ◽  
Plant Size ◽  
Damage Function ◽  
Point Of View ◽  
Daily Maximum ◽  
Replacement Series

Effects of mixed intercropping on plant size, content of mineral nutrients and biomass yields were examined in three field experiments in Southern Finland in 1983—1985. The stand types were monocrops and replacement series of mixtures with 2/3 and 1/3 or 1/3 and 2/3 of oats (Avena sativa) and faba bean (Vicia faba), respectively. In one of the experiments control of R. padi, by means of deltamethrin sprayings, was an additional experimental factor having two levels. The height of stems or the above ground biomass of oats either were not affected or were increased by crop diversification. Bean plants remained smaller in the mixtures than in the monocrop. In plant size, there was a significant interaction between stand type and the effect of aphicide spraying: Oat benefitted most from being grown in the mixture containing most bean, and there was an indication (not statistically significant) that in these mixtures bean had proportionately higher weight loss. This result was interpreted as giving some support to the hypothesis of interspecific compensation between oats and bean against aphid damage to oats. In oats, the content of N, P, K, Ca, and Mg all decreased from the stage of inflorescence emergence to the stage of the onset of milk development. Mixed cropping increased the content in oats of all these nutrients except Ca. At the same time, contents of P and K in bean were decreased. The changes in growth form and composition in oats induced by intercropping are discussed from the point of view of host plant relationship and damage function of the aphid pest. In terms of relative yield total (RYT), there was no overyielding in the dry matter, and in one case only was there overyielding in the nitrogen. During the period of population growth of R. padi, the daily maximum temperatures within the canopy were higher in the mixtures than in the monocrop of oats.

Response of Weeds to Tillage and Cover Crop Residue

Weed Science ◽  
1991 ◽  
Vol 39 (2) ◽  
pp. 195-199 ◽  
Author(s):  
John R. Teasdale ◽  
C. Edward Beste ◽  
William E. Potts
Keyword(s):  
Cover Crop ◽  
Crop Residue ◽  
Conventional Tillage ◽  
No Tillage ◽  
Hairy Vetch ◽  
Common Lambsquarters ◽  
Weed Density ◽  
Tillage Treatment ◽  
Crop Biomass ◽  
Large Crabgrass

Total weed density increased after 1 yr of no-tillage and after 2 yr of conventional tillage in a 4-yr experiment with repeated assignment of the same treatment to the same plots. Large crabgrass, goosegrass, and carpetweed densities were higher in the no-tillage compared with the conventional-tillage treatment in at least 1 yr whereas common lambsquarters density was greater in the conventional-tillage treatment the last year of the experiment. Within the no-tillage treatment, rye or hairy vetch residue reduced total weed density an average of 78% compared to the treatment without cover crop when cover crop biomass exceeded 300 g m–2and when residue covered more than 90% of the soil. Goosegrass, stinkgrass, and carpetweed densities were reduced by cover crop residue in at least 1 yr whereas large crabgrass was unaffected. Common lambsquarters density increased where rye was grown as a cover crop prior to conventional tillage. Despite differences in weed density among treatments, weed biomass was equivalent in all treatments during the last 2 yr.

scholarly journals Systemic Colonization by Metarhizium robertsii Enhances Cover Crop Growth

2020 ◽  
Vol 6 (2) ◽  
pp. 64
Author(s):  
Imtiaz Ahmad ◽  
María del Mar Jiménez-Gasco ◽  
Dawn S. Luthe ◽  
Mary E. Barbercheck
Keyword(s):  
Cover Crops ◽  
Cover Crop ◽  
Field Experiments ◽  
Negative Relationship ◽  
Crop Growth ◽  
Above Ground Biomass ◽  
Crop Species ◽  
Metarhizium Robertsii ◽  
Cereal Rye ◽  
Ground Biomass

Fungi in the genus Metarhizium (Hypocreales: Clavicipitaceae) are insect pathogens that can establish as endophytes and can benefit their host plant. In field experiments, we observed a positive correlation between the prevalence of M. robertsii and legume cover crops, and a negative relationship with brassicaceous cover crops and with increasing proportion of cereal rye in mixtures. Here, we report the effects of endophytic M. robertsii on three cover crop species under greenhouse conditions. We inoculated seeds of Austrian winter pea (Pisum sativum L., AWP), cereal rye (Secale cereale L.), and winter canola (Brassica napus L.) with conidia of M. robertsii to assess the effects of endophytic colonization on cover crop growth. We recovered M. robertsii from 59%, 46%, and 39% of seed-inoculated AWP, cereal rye, and canola plants, respectively. Endophytic M. robertsii significantly increased height and above-ground biomass of AWP and cereal rye but did not affect chlorophyll content of any of the cover crop species. Among inoculated plants from which we recovered M. robertsii, above-ground biomass of AWP was positively correlated with the proportion of colonized root but not leaf tissue sections. Our results suggest that winter cover crops may help to conserve Metarhizium spp. in annual cropping systems.

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