RELATIONSHIP BETWEEN PERCENTAGE EMERGENCE AND GROWING DEGREE DAYS FOR CORN

1990 ◽  
Vol 70 (3) ◽  
pp. 493-497 ◽  
Author(s):  
H. N. HAYHOE ◽  
L. M. DWYER
Keyword(s):  
Zea Mays L ◽  
Conservation Tillage ◽  
Logistic Function ◽  
Growing Degree Days ◽  
Degree Days ◽  
Tillage Practices ◽  
Bed Temperature ◽  
Response To Temperature ◽  
Production Areas ◽  
Emergence Response

Seed bed temperature is often the limiting environmental factor affecting corn (Zea mays L.) emergence, particularly in short-season production areas or when conservation tillage practices are employed. In this study, observations of the percentage emergence and seed bed growing degree days (base 10 °C) are used to assess functions which model the emergence response to temperature. Key words: Percentage emergence, growing degree days, log transformation, logistic function

PREDICTION OF SOIL TEMPERATURE FROM AIR TEMPERATURE FOR ESTIMATING CORN EMERGENCE

1990 ◽  
Vol 70 (3) ◽  
pp. 619-628 ◽  
Author(s):  
L. M. DWYER ◽  
H. N. HAYHOE ◽  
J. L. B. CULLEY
Keyword(s):  
Nonlinear Response ◽  
Zea Mays L ◽  
Thermal Environment ◽  
Growing Degree Days ◽  
Degree Days ◽  
Emergence Period ◽  
Air Temperatures ◽  
Soil Temperatures ◽  
Production Areas ◽  
Zone Temperature

The soil thermal environment is critical to corn (Zea mays L.) emergence in short-season production areas. A field study was therefore carried out during the emergence period to test a method to predict 0.05-m soil temperatures from air temperatures and to develop a method to quantify emergence rates as a function of actual and predicted soil thermal units. Thermal units (base 10 °C) were calculated from hourly air and measured and predicted 0.05-m soil temperatures; these thermal units were fit to test emergence data collected on six cultivars. The nonlinear response of percentage emergence to thermal units was approximated by an exponential function. Comparisons of cultivar emergence rates, expressed as the number of thermal units to 0 and 75% emergence, statistically differentiated (P ≤ 0.05) the test cultivars into three main groupings. When predicted soil temperatures were used to calculate the number of thermal units, the thermal units to specific emergence levels were within the equivalent of 1 or 2 d of those generated using measured soil temperatures.Key words: Growing degree days, regression, thermal regimes, seed zone temperature, corn emergence

Forest ecotone response to climate change: sensitivity to temperature response functional forms

2000 ◽  
Vol 30 (10) ◽  
pp. 1632-1645 ◽  
Author(s):  
Craig Loehle
Keyword(s):  
Response Function ◽  
Large Scale ◽  
Temperature Response ◽  
Tree Height ◽  
Growing Degree Days ◽  
Degree Days ◽  
Functional Responses ◽  
New Model ◽  
Functional Forms ◽  
Response To Temperature

Past simulation studies using a variety of models have generally agreed that climatic warming could have adverse effects on forests, including large-scale diebacks in some regions and drastic range shrinkages of many species. These effects should be most evident at biome transition zones. Other studies have pointed out, however, that past models have used a parabolic temperature response function that is based on geographic range limits rather than functional responses or data and that this parabolic model could exaggerate dieback effects. A new model is proposed for growing degree-days temperature response, which is asymptotic rather than parabolic. In this new model, tree height growth rate increases and then levels off with increasing growing degree-days. Species from more southern regions have a higher asymptote. It is shown that this model can be derived from the integration of a parabolic growth response to temperature over a year-long sinusoidal temperature regime. The SORTIE forest simulation model was modified to incorporate this response function. An ecotonal region was simulated under a warming scenario. The traditional parabolic temperature response model produced a wide zone of dieback following warming. In contrast, the new asymptotic response function produced no dieback and a stable ecotone that migrated north at <100 m/100 years.

Influence of sowing dates on the growing degree days and phenology of winter maize (Zea mays L.)

1986 ◽  
Vol 38 (1-3) ◽  
pp. 47-57 ◽  
Author(s):  
S.S. Narwal ◽  
S. Poonia ◽  
G. Singh ◽  
D.S. Malik
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Growing Degree Days ◽  
Degree Days ◽  
Sowing Dates

scholarly journals Prediction of phenological stages of six maize (Zea mays L.) hybrids based on required growing degree days

2020 ◽  
Vol 8 (3) ◽  
pp. 2564-2574
Author(s):  
Ravi Babu M ◽  
Rao KLN ◽  
Ashokarani Y ◽  
Martiluther M ◽  
Prasad PRK
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Growing Degree Days ◽  
Degree Days ◽  
Phenological Stages

Influences of Conservation Tillage Practices on Farmland Soil Ecological Factors and Productive Benefits in Dryland Region with Triple Cropping System

2013 ◽  
Vol 39 (10) ◽  
pp. 1880
Author(s):  
Long-Chang WANG ◽  
Cong-Ming ZOU ◽  
Yun-Lan ZHANG ◽  
Sai ZHANG ◽  
Xiao-Yu ZHANG ◽  
...  
Keyword(s):  
Conservation Tillage ◽  
Ecological Factors ◽  
Cropping System ◽  
Tillage Practices ◽  
Farmland Soil

Evaluation of Finger Millet Varieties under Rainfed Condition of Eastern India

2017 ◽  
Vol 4 (03) ◽  
Author(s):  
M. K. Singh ◽  
VINOD KUMAR ◽  
SHAMBHU PRASAD
Keyword(s):  
Field Experiment ◽  
Finger Millet ◽  
Yield Potential ◽  
Growing Degree Days ◽  
Eastern India ◽  
Degree Days ◽  
Rainfed Condition ◽  
Net Returns ◽  
Humid Environment ◽  
Use Efficiency

A field experiment was carried out during the kharif of 2014 and 2015 to evaluate the yield potential, economics and thermal utilization in eleven finger millet varieties under the rainfed condition of the sub-humid environment of South Bihar of Eastern India. Results revealed that the significantly higher grain yield (20.41 q ha-1), net returns (Rs 25301) and B: C ratio (1.51) was with the finger millet variety ‘GPU 67’ but was being at par to ‘GPU28’and ‘RAU-8’, and significantly superior over remaining varieties. The highest heat units (1535.1oC day), helio-thermal units (7519.7oC day hours), phenothermal index (19.4 oC days day-1) were recorded with variety ‘GPU 67’ followed by ‘RAU 8’ and ‘GPU 28’ and lowest in ‘VL 149’ at 50 % anthesis stage. Similarly, the highest growing degree days (2100 oC day), helio-thermal units (11035.8 oC day hours) were noted with ‘GPU 67’ followed by ‘RAU 8’ and ‘GPU 28’ at maturity. The highest heat use efficiency (0.97 kg ha-1 oC day) and helio-thermal use efficiency (0.19 kg ha-1 oC day hour) were in ‘GPU 67’ followed by ‘VL 315’.

scholarly journals Determining the critical period for weed control in high-yielding cotton using common sunflower as a mimic weed

2019 ◽  
Vol 33 (6) ◽  
pp. 800-807 ◽  
Author(s):  
Graham W. Charles ◽  
Brian M. Sindel ◽  
Annette L. Cowie ◽  
Oliver G. G. Knox
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Yield Loss ◽  
Field Studies ◽  
Growing Degree Days ◽  
Degree Days ◽  
Weed Density ◽  
High Level ◽  
The Cost ◽  
Planting Season

AbstractField studies were conducted over six seasons to determine the critical period for weed control (CPWC) in high-yielding cotton, using common sunflower as a mimic weed. Common sunflower was planted with or after cotton emergence at densities of 1, 2, 5, 10, 20, and 50 plants m−2. Common sunflower was added and removed at approximately 0, 150, 300, 450, 600, 750, and 900 growing degree days (GDD) after planting. Season-long interference resulted in no harvestable cotton at densities of five or more common sunflower plants m−2. High levels of intraspecific and interspecific competition occurred at the highest weed densities, with increases in weed biomass and reductions in crop yield not proportional to the changes in weed density. Using a 5% yield-loss threshold, the CPWC extended from 43 to 615 GDD, and 20 to 1,512 GDD for one and 50 common sunflower plants m−2, respectively. These results highlight the high level of weed control required in high-yielding cotton to ensure crop losses do not exceed the cost of control.

Simultaneous Adoption of Herbicide-Resistant and Conservation-Tillage Cotton Technologies

2006 ◽  
Vol 38 (3) ◽  
pp. 629-643 ◽  
Author(s):  
Roland K. Roberts ◽  
Burton C. English ◽  
Qi Gao ◽  
James A. Larson
Keyword(s):  
Logit Model ◽  
Conservation Tillage ◽  
Bayes Theorem ◽  
Cotton Production ◽  
Herbicide Resistant ◽  
Tillage Practices ◽  
Herbicide Use ◽  
Residual Herbicide ◽  
The Relationship ◽  
Simultaneous Adoption

If adoption of herbicide-resistant seed and adoption of conservation-tillage practices are determined simultaneously, adoption of herbicide-resistant seed could indirectly reduce soil erosion and adoption of conservation-tillage practices could indirectly reduce residual herbicide use and increase farm profits. Our objective was to evaluate the relationship between these two technologies for Tennessee cotton production. Evidence from Bayes' theorem and a two-equation logit model suggested a simultaneous relationship. Mean elasticities for acres in herbicide-resistant seed with respect to the probability of adopting conservation-tillage practices and acres in conservation-tillage practices with respect to the probability of adopting herbicide-resistant seed were 1.74 and 0.24, respectively.

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