<i>Estimating Corn Emergence Date using UAV-based Imagery</i>

2020 ◽  
Author(s):  
Chin Nee Vong ◽  
Stirling A. Stewart ◽  
Jianfeng Zhou ◽  
Newell R. Kitchen ◽  
Kenneth A. Sudduth
Keyword(s):  
Emergence Date

scholarly journals Insect body size changes under future warming projections: a case study of Chironomidae (Insecta: Diptera)

Hydrobiologia ◽  
2021 ◽  
Author(s):  
Rungtip Wonglersak ◽  
Phillip B. Fenberg ◽  
Peter G. Langdon ◽  
Stephen J. Brooks ◽  
Benjamin W. Price
Keyword(s):  
Body Size ◽  
Ambient Temperature ◽  
Wing Length ◽  
The Body ◽  
Mesocosm Experiments ◽  
Future Warming ◽  
Increasing Temperature ◽  
Emergence Date ◽  
Average Body

AbstractChironomids are a useful group for investigating body size responses to warming due to their high local abundance and sensitivity to environmental change. We collected specimens of six species of chironomids every 2 weeks over a 2-year period (2017–2018) from mesocosm experiments using five ponds at ambient temperature and five ponds at 4°C higher than ambient temperature. We investigated (1) wing length responses to temperature within species and between sexes using a regression analysis, (2) interspecific body size responses to test whether the body size of species influences sensitivity to warming, and (3) the correlation between emergence date and wing length. We found a significantly shorter wing length with increasing temperature in both sexes of Procladius crassinervis and Tanytarsus nemorosus, in males of Polypedilum sordens, but no significant relationship in the other three species studied. The average body size of a species affects the magnitude of the temperature-size responses in both sexes, with larger species shrinking disproportionately more with increasing temperature. There was a significant decline in wing length with emergence date across most species studied (excluding Polypedilum nubeculosum and P. sordens), indicating that individuals emerging later in the season tend to be smaller.

Early Classification Method for US Corn and Soybean by Incorporating MODIS-Estimated Phenological Data and Historical Classification Maps in Random-Forest Regression Algorithm

2021 ◽  
Vol 87 (10) ◽  
pp. 747-758
Author(s):  
Toshihiro Sakamoto
Keyword(s):  
Random Forest ◽  
Classification Accuracy ◽  
Classification Method ◽  
Estimation Accuracy ◽  
Random Forest Regression ◽  
Crop Phenology ◽  
Phenological Data ◽  
Mixed Pixel ◽  
Crop Classification ◽  
Emergence Date

An early crop classification method is functionally required in a near-real-time crop-yield prediction system, especially for upland crops. This study proposes methods to estimate the mixed-pixel ratio of corn, soybean, and other classes within a low-resolution MODIS pixel by coupling MODIS-derived crop phenology information and the past Cropland Data Layer in a random-forest regression algorithm. Verification of the classification accuracy was conducted for the Midwestern United States. The following conclusions are drawn: The use of the random-forest algorithm is effective in estimating the mixed-pixel ratio, which leads to stable classification accuracy; the fusion of historical data and MODIS-derived crop phenology information provides much better crop classification accuracy than when these are used individually; and the input of a longer MODIS data period can improve classification accuracy, especially after day of year 279, because of improved estimation accuracy for the soybean emergence date.

scholarly journals The Effect of Conspecific Density on Emergence ofLestes bipupillatusCalvert, 1909 (Odonata: Lestidae)

2014 ◽  
Vol 2014 ◽  
pp. 1-3 ◽  
Author(s):  
Ricardo Cardoso-Leite ◽  
Gabriel C. Vilardi ◽  
Rhainer Guillermo-Ferreira ◽  
Pitágoras C. Bispo
Keyword(s):  
Population Dynamics ◽  
Density Dependence ◽  
Social Environment ◽  
Growth Rates ◽  
High Density ◽  
Conspecific Density ◽  
Simulated Environments ◽  
The Social ◽  
Emergence Date

Conspecific density may influence adult recruitment and consequently population dynamics. Several studies have shown the density dependence of larvae growth rates in Odonata. However, few studies studied how conspecific density influence final instar larvae emergence date decisions. Considering that larvae may choose the date of emergence, the present study investigated if density affects larvae choice. For this, we reared eight final instar larvae in individual aquaria and other 24 larvae in aquaria with three larvae each. This way, we simulated environments with low and high larval densities. We then noted the days that larvae took to emerge and compared it between low and high density groups. The results showed that larvae seem to emerge earlier when in high densities (Mann-Whitney,U=10.000,P=0.03). These results support the hypothesis that damselfly last instar larvae may postpone or hasten emergence in response to the social environment and related constraints.

Emergence characteristics of four annual weed species

Weed Science ◽  
1999 ◽  
Vol 47 (5) ◽  
pp. 578-584 ◽  
Author(s):  
Robert G. Hartzler ◽  
Douglas D. Buhler ◽  
David E. Stoltenberg
Keyword(s):  
Initial Time ◽  
Grass Species ◽  
First Year ◽  
Weed Species ◽  
Emergence Period ◽  
Seed Sources ◽  
Amaranthus Rudis ◽  
Eriochloa Villosa ◽  
Broadleaf Species ◽  
Emergence Date

Emergence characteristics, including initial time of emergence, magnitude of emergence, and mean time of emergence, ofAmaranthus rudisSauer,Setaria faberiHerrm.,Eriochloa villosa(Thunb.) Kunth, andAbutilon theophrastiMedik. were studied in central Iowa during the first 3 yr following burial of seed collected and buried in the fall of 1994 or 1995. Although the initial emergence date varied among years, the emergence sequence among species was consistent.Eriochloa villosaand A.theophrastiwere the first species to emerge, with initial emergence occurring between April 28 and May 10. Initial emergence dates for these species were the same, except for 1995 whenA. theophrastiemerged 4 d prior toE. villosa. Amaranthus rudiswas the last species to emerge, with initial emergence ranging from 5 to 25 d afterA. theophrasti.First-year emergence in 1995 was 8% forA. theophrasti, 7% for A.rudis, 41% forE. villosa, and 33% forS. faberi, based on the number of buried seed. Proportional emergence during the first year following burial in 1996 was similar to 1995 forA. theophrastiandS. faberi, but greater emergence was observed in 1996 forE. villosaandA. rudis.During the 3 yr of both studies, cumulative emergence of the two grass species (43 to 71%) was higher than for the broadleaf species (13 to 35%). A high percentage of the total annual emergence ofE. villosaoccurred within the first 2 wk of initial emergence, whereas a high percentage ofA. rudisemergence occurred late in its emergence period. Emergence characteristics of the four species were consistent among years and seed sources.

Emergence date mediation of rice yield responses to equidistant spacing

1995 ◽  
Vol 41 (3) ◽  
pp. 167-171 ◽  
Author(s):  
Paul A. Counce ◽  
Terry C. Keisling
Keyword(s):  
Rice Yield ◽  
Yield Responses ◽  
Emergence Date

Interference of Redroot Pigweed (Amaranthus retroflexus) in Corn (Zea mays)

Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 568-573 ◽  
Author(s):  
Stevan Z. Knezevic ◽  
Stephan F. Weise ◽  
Clarence J. Swanton
Keyword(s):  
Zea Mays ◽  
Grain Yield ◽  
Seed Production ◽  
Field Experiments ◽  
Amaranthus Retroflexus ◽  
Corn Yield ◽  
Leaf Stage ◽  
Redroot Pigweed ◽  
Emergence Date

Redroot pigweed is a major weed in corn throughout Ontario. Field experiments were conducted at two locations in 1991 and 1992 to determine the influence of selected densities and emergence times of redroot pigweed on corn growth and grain yield. Redroot pigweed densities of 0.5, 1, 2, 4 and 8 plants per m of row were established within 12.5 cm on either side of the corn row. In both years, redroot pigweed seeds were planted concurrently and with corn at the 3- to 5-leaf stage of corn growth. A density of 0.5 redroot pigweed per m of row from the first (earlier) emergence date of pigweed (in most cases, up to the 4-leaf stage of corn) or four redroot pigweed per m of row from the second (later) emergence date of pigweed (in most cases, between the 4- and 7-leaf stage of corn) reduced corn yield by 5%. Redroot pigweed emerging after the 7-leaf stage of corn growth did not reduce yield. Redroot pigweed seed production was dependent upon its density and time of emergence. The time of redroot pigweed emergence, relative to corn, may be more important than its density in assessing the need for postemergence control.

scholarly journals Interaction of Shoot Emergence Date and Long Days after Controlled-temperature forcing of `Nellie White' Easter Lilies

1993 ◽  
Vol 118 (6) ◽  
pp. 741-746
Author(s):  
John M. Dole
Keyword(s):  
Plant Height ◽  
Lilium Longiflorum ◽  
Emergence Time ◽  
Easter Lily ◽  
Emergence Date ◽  
Shoot Emergence

`Nellie White' Easter lily bulbs (Lilium longiflorum Thunb.) were given 6 weeks of 5.5C, placed in the greenhouse, and divided into groups based on number of days to emergence: 0 to 6, 7 to 13, 14 to 20, or 21 to 27 days. At emergence, the shoots received 0, 1, 2, or 3 weeks of long days (LDs). The experiment was repeated for 3 consecutive years. Late-emerging plants had fewer days from emergence to visible bud and anthesis than early-emerging plants. Consequently, late-emerging plants flowered within 3 to 11 days of early emerging plants despite 16 to 22 days difference in emergence time. Late-emerging plants were tallest, while plants emerging in the second week had the most leaves. Flower count was not influenced by emergence date in Year 1. In Year 2, flower count decreased curvilinearly with later emergence. In Year 3, flower count was highest in plants emerging in the second week and lowest in the last week. Increasing LDs decreased the number of days from emergence to visible bud and anthesis but increased plant height. LDs did not affect leaf count in any year or flower count in Years 1 and 2. In Year 3, flower count increased with increasing weeks of LDs. LD × emergence date interactions existed, but varied from year to year.

Host Plant Quality and Male Wheat Stem Sawfly (Hymenoptera: Cephidae) Fitness

2000 ◽  
Vol 35 (4) ◽  
pp. 478-482 ◽  
Author(s):  
Wendell L. Morrill ◽  
David K. Weaver
Keyword(s):  
Host Plant ◽  
Adult Male ◽  
Mating Success ◽  
Significant Relationship ◽  
Wing Length ◽  
Plant Quality ◽  
Host Plant Quality ◽  
Wheat Stem Sawfly ◽  
Cephus Cinctus ◽  
Emergence Date

The size of male Cephus cinctus Norton (Hymenoptera: Cephidae) adults did not significantly increase with the size of host stems in which larvae developed. Larger adult male sawflies had higher longevity. There was no statistically significant relationship between wing length and the emergence date, mating success, or dispersal from overwintering sites. The relation of host plant quality and sawfly fitness was less apparent for male adults than that which we previously reported for females.

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