AN EVALUATION OF THE CORN HEAT UNIT SYSTEM FOR THE SHORT-SEASON GROWING REGIONS ACROSS CANADA

1983 ◽  
Vol 63 (1) ◽  
pp. 121-130 ◽  
Author(s):  
D. J. MAJOR ◽  
D. M. BROWN ◽  
A. BOOTSMA ◽  
G. DUPUIS ◽  
N. A. FAIREY ◽  
...  
Keyword(s):  
Temperature Adaptation ◽  
Genotypic Differences ◽  
Growing Degree Days ◽  
Thermal Unit ◽  
Degree Days ◽  
Weather Factors ◽  
Heat Unit ◽  
Corn Hybrids ◽  
Unit System ◽  
Different Climates

A study was conducted at 11 locations across Canada to determine if corn hybrids have different corn heat unit (CHU) requirements in different climates. The study included six hybrids, four each in the three years 1977–1979. Differences in the time between planting and emergence were attributable to slow emergence of two hybrids as well as management and weather factors at different locations. Genotypic differences were expressed mainly in the period between emergence and anthesis. At three locations, 198 CHU more were required than at other locations. In the period from anthesis to 45% ear moisture, two hybrids required more CHU than other hybrids. These extra CHU requirements were not related to hybrid rating, i.e., late-maturing hybrids did not require more CHU to complete the ripening phase. In a comparison of growing degree days (GDDi) with bases ranging from 5 to 15 °C, no one thermal unit had sufficient advantage over the CHU system to warrant its adoption in Canada. Further, calendar days were the best for predicting the duration of the period from planting to emergence. The period from emergence to 10% anthesis was least variable of all the stages and could be predicted accurately by any of the methods.Key words: Zea mays, temperature, adaptation, thermal units

scholarly journals Spatial Soil Temperature and Moisture Monitoring Across the Transylvanian Plain in Romania

2010 ◽  
Vol 67 (1) ◽  
Author(s):  
Beatrix HAGGARD ◽  
Teodor RUSU ◽  
David WEINDORF ◽  
Horea CACOVEAN ◽  
Paula MORARU ◽  
...  
Keyword(s):  
Best Management Practices ◽  
Management Practices ◽  
Spline Interpolation ◽  
Planting Date ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Degree Days ◽  
Corn Hybrids ◽  
Important Region ◽  
Soil Temperatures

The Transylvanian Plain, Romania is an important region for agronomic productivity. However, limited soils data and adoption of best management practices hinder land productivity. Soil temperatures of the Transylvanian Plain were evaluated using a set of twenty datalogging stations positioned throughout the plain. Soil temperatures were monitored at the surface and at 10, 30, and 50 cm depths, and soil moisture was monitored at 10 cm. Preliminary results indicate that most soils of the Transylvanian Plain will have a mesic temperature regime. However, differences in seasonal warming and cooling trends across the plain were noted. These have important implications for planting recommendations. Growing degree days (GDDs) are preferred over maturity ratings, because they can account for temperature anomalies. The crop being considered for this study was corn. The base temperature (BT) was set at 10oC, and the upper threshold was 30oC. Two methods were used to calculate GDDs; 1) minimum and maximum daily temperatures, and 2) 24 h of averaged temperature data. Growing degree days were run from 110-199 day of year (DOY) to represent approximate planting date to tasseling. The DOY that 694 accumulated growing degree days (AGDDs) was reached at each site was then analyzed to identify differences across the TP. Three sites failed to reach 694 AGDDs by DOY 199, and were excluded from comparisons to other results. Averaged values were used to create spline interpolation maps with ArcMap 9.2 (ESRI, Redlands, CA, USA). The southeastern portion of the TP was found to tassel a month earlier assuming a planting date of 109 DOY. Four DeKalb® corn hybrids were then selected based on GDDs to tasseling, drydown, drought tolerance, and insect resistance. With a better understanding of the GDD trends across the TP, more effective planting and harvesting could be accomplished by Romanian farmers to maximize agronomic production.

scholarly journals Improving the Prediction of Processing Pea Maturity Based on the Growing-degree Day Approach

HortScience ◽  
2000 ◽  
Vol 35 (4) ◽  
pp. 611-614 ◽  
Author(s):  
Gaétan Bourgeois ◽  
Sylvie Jenni ◽  
Hélène Laurence ◽  
Nicolas Tremblay
Keyword(s):  
Current Model ◽  
Climatic Conditions ◽  
Developmental Period ◽  
Temperature Data ◽  
Growing Degree Days ◽  
Base Temperature ◽  
Degree Days ◽  
Planting Dates ◽  
Average Temperature ◽  
Unit System

The heat-unit system, involving the sum of daily mean temperatures above a given base temperature, is used with processing pea (Pisum sativum L.) to predict relative maturity during the growing season and to schedule planting dates based on average temperature data. The Quebec pea processing industry uses a base temperature of 5 °C to compute growing-degree days (GDD) between sowing and maturity. This study was initiated to verify if the current model, which uses a base temperature of 5 °C, can be improved to predict maturity in Quebec. Four pea cultivars, `Bolero', `Rally', `Flair', and `Kriter', were grown between 1985 and 1997 on an experimental farm in Quebec. For all cultivars, when using a limited number of years, a base temperature between 0.0 and 0.8 °C reduced the coefficient of variation (cv) as compared with 5.0 °C, indicating that the base temperature used commercially is probably not the most appropriate for Quebec climatic conditions. The division of the developmental period into different stages (sowing until emergence, emergence until flowering, and flowering until maturity) was also investigated for some years. Use of base temperatures specific for each crop phase did not improve the prediction of maturity when compared with the use of an overall base temperature. All years for a given cultivar were then used to determine the base temperature with the lowest cv for predicting the time from sowing to maturity. A base temperature from 0 to 5 °C was generally adequate for all cultivars, and a common base temperature of 3.0 °C was selected for all cultivars. For the years and cultivars used in this study, the computation of GDD with a base temperature of 3 °C gave an overall prediction of maturity of 2.0, 2.4, 2.2, and 2.5 days based on the average of the absolute values of the differences for the cultivars Bolero, Rally, Flair, and Kriter, respectively.

scholarly journals Heat unit requirement and yield of wheat (Triticum aestivum L.) varieties under different growing environment in mid hill conditions of Himachal Pradesh

2021 ◽  
Vol 21 (3) ◽  
pp. 282-287
Author(s):  
RANU PATHANIA ◽  
RAJENDRA PRASAD ◽  
RANBIR SINGH RANA ◽  
S. K. MISHRA
Keyword(s):  
Triticum Aestivum ◽  
Grain Yield ◽  
Wheat Variety ◽  
Triticum Aestivum L ◽  
Growing Degree Days ◽  
Thermal Unit ◽  
Degree Days ◽  
Sowing Time ◽  
Sowing Dates ◽  
And Performance

A eld experiment was conducted during rabi seasons of 2015-16 and 2016-17 to study the accumulated growing degree days (GDD), helio-thermal unit (HTU), photo-thermal unit (PTU), heat use efciencies (HUE) at different phenological stages and performance of wheat (Triticum aestivum L.) varieties grown under different sowing dates. Results of present study revealed that the crop sown on 20th October required maximum calendar days, growing degree days, photo-thermal unit and helio-thermal unit for tillering, owering, earing and maturity which was signicantly reduced with subsequent delay in sowing time. The grain yield recorded in 20th November (4065 kgha-1) was statistically at par with 5th November yield (3863 kgha-1). The signicant reduction in grain yield on varieties was recorded when sowing was delayed beyond 20th November. Among the varieties 'VL-907' produced highest grain yield(3771 kgha-1) which was statistically on par with 'VL-829' (3726 kgha-1). The early and timely sown wheat  variety like VL-829 and VL-907 took highest calendar days, GDD, HTU and PTU for earing and maturity. The variety 'VL-907' recorded the highest grain yield (4196 and 4168 kgha-1) at 5th and 20th November sowing as compared to all other sowing dates.

scholarly journals Comparison of seasonal thermal indices for measurement of corn maturity in a prairie environment

1992 ◽  
Vol 72 (4) ◽  
pp. 1157-1162 ◽  
Author(s):  
S. Plett
Keyword(s):  
Correlation Coefficients ◽  
Growing Degree Days ◽  
Degree Days ◽  
Thermal Indices ◽  
Corn Hybrids ◽  
Thermal Index ◽  
Heat Units ◽  
Coefficients Of Variation ◽  
Grain Moisture ◽  
Specific Stage

This study was initiated to determine (i) which thermal index — corn heat units (CHU), modified CHUs (mCHU) or growing degree–days (GDD) — was most consistent across years and locations and (ii) which maturity index — 50% silk, time to 30% grain moisture or time to 100% milk line — was the most consistent measure. Fifteen corn hybrids were evaluated at Morden and Brandon, Manitoba, over 3 yr (1988–1990). Correlation coefficients between total accumulation of thermal units from planting to first frost and thermal units required to reach a specific stage of maturity ranged from 0.283 to 0.969. The lowest correlations were between CHU and time to 50% silk. Coefficients of variation (CVs) were always lower for CHU than for either mCHU or GDD. CV was highest for time to 100% milk line but similar between time to 50% silk and time to 30% grain moisture. Correlations between ranking of hybrids across site–years was highest for mCHU. Overall ranking of thermal indices for consistency was CHU > GDD > mCHU. Time to 50% silk was the most consistent of the measures of maturity. Time to 30% grain moisture was a more consistent measure of maturity than time to 100% milk line.Key words: Maize, heat units, growing degree–days, milk line, grain moisture

scholarly journals Thermal unit requirement of grape (Vitis vinifera L.) varieties under south western Punjab conditions

2021 ◽  
Vol 22 (4) ◽  
pp. 469-476
Author(s):  
NAVJOT GUPTA ◽  
RAJ KUMAR PAL ◽  
AMARDEEP KOUR ◽  
S. K. MISHRA
Keyword(s):  
Thermal Response ◽  
Vitis Vinifera L ◽  
Growing Degree Days ◽  
Thermal Unit ◽  
Degree Days ◽  
Long Duration ◽  
Early Ripening ◽  
Use Efficiency ◽  
Grape Varieties ◽  
Minimum Heat

Weather components have significant impact on the phenology of fruit plants. In order to study the effect of heat, photothermal and heliothermal units on phenology of grapes, an experiment was conducted during 2016 and 2017 on eleven grape varieties. The weather based indices were used for characterizing the thermal response to various phenophases of different grape varieties. Based on the thermal response the eleven varieties were classified into early, mid and late maturing categories. The fruit ripening was differed by 7-9 days for early, 4-8 days for mid and 1-3 days for late ripening groups. For early, mid and late maturing varieties the accumulated range of growing degree days was 1303-1530, 1617-1712 and 1912-1959 °C day, photothermal unit was 15971-19032, 20201-21484 and 24255-24923°C day. Likewise, minimum heliothermal unit was required by early ripening varieties i.e., Himrod(9973 °C days) and Madeliene Anguvine (11235 °C days) but, maximum for long duration varieties like Black Muscat (15000 days) and Angur Early (14579 °C days). Maximum and minimum heat use efficiency was recorded by variety Perlette (1.57) and Black Muscat (0.96), respectively. 

Weed Management in Lettuce (Lactuca Sativa) with Preplant Irrigation

2006 ◽  
Vol 20 (4) ◽  
pp. 1058-1065 ◽  
Author(s):  
Shachar Shem-Tov ◽  
Steve A. Fennimore ◽  
W. Thomas Lanini
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Cultural Practice ◽  
Growing Degree Days ◽  
Degree Days ◽  
Heat Unit ◽  
Weed Density ◽  
Cropping Season ◽  
Hand Weeding ◽  
Effective Use

During dry weather, preplant irrigation of raised beds followed by shallow tillage to create a smooth planting bed is necessary to establish a good lettuce stand. Depletion of germinable weed seeds in the top 5 cm of soil by the sequence of preplant irrigation, followed 7 to 14 d later by shallow tillage to prepare a seedbed, reduces weed density in the subsequent crop. Preplant irrigation and tillage reduces weed density and, when used together with preplant herbicide, provides effective weed control in the cropping season. Preplant and in-crop weed densities resulting from furrow or sprinkler preplant irrigation, followed by shallow tillage and lettuce planting 7 or 14 d later, were compared with the no preplant irrigation control. During the 14-d preplant period, up to 127 weeds/m2emerged and were removed by shallow tillage before crop planting. Preplant irrigation and shallow tillage reduced in-crop weed density by up to 77% and reduced hand-weeding and crop-thinning time by up to 50% compared with the no preplant irrigation and no herbicide control. Delaying tillage for 14 d following preplant irrigation provided sufficient time for adequate heat unit accumulation (>120 growing degree days, base 10 C), allowing for many weeds to germinate and be killed by shallow tillage. However, 7 d between preplant irrigation and tillage resulted in less heat unit accumulation (<50 growing degree days, base 10 C) and less weed germination before tillage. Preplant irrigation together with pronamide at either 0.67 or 1.34 kg ai/ha reduced weed density compared with the no preplant irrigation. Effective use of preplant irrigation and preplant weed removal may increase the consistency of weed control with lower pronamide rates. Preplant irrigation followed by shallow tillage is an effective cultural practice to control in-crop weeds for conventional lettuce production.

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’.

Effect of micronutrients foliar spray on thermal Indices, phenology and yield of Lentil in new Alluvial Zone of West Bengal

2020 ◽  
Vol 7 (04) ◽  
Author(s):  
V VISHA KUMARI ◽  
PURABI BANERJEE ◽  
ROSHNI VIJAYAN ◽  
RAJIB NATH ◽  
KAJAL SENGUPTA ◽  
...  
Keyword(s):  
West Bengal ◽  
Foliar Spray ◽  
Control Treatment ◽  
Thermal Unit ◽  
Degree Days ◽  
Thermal Indices ◽  
Sowing Dates ◽  
Stover Yield ◽  
Yield Responses ◽  
Sunshine Hour

A field experiment was conducted at BCKV during Rabi, 2018-19 and 2019-20 to study the effect of Zn, Fe and B foliar spray on phenology and thermal indices of popular lentil variety, Moitree (WBL 77) under different sowing condition [1st week of November (normal) and 1st week of December (late)]. Delay in sowing of crop from November to December reduced the crop duration by 11.4 days (113.4 days vs 101.7 days). The variation in mean daily temperature and bright sunshine hour among two sowing dates resulted in varied accumulated Growing Degree Days (GDD), Helio Thermal Units (HTU) as well as Photo Thermal Unit (PTU). It was found that different dates of sowing have a larger impact on change in phenology of the crop and thus affect various thermal indices. Foliar spraying of micronutrients viz., B + Fe @ 0.5% produced significantly higher seed and stover yield of 1438 kg ha-1 and 3981 kg ha-1 respectively, which were 86.26% and 27.0% more than that obtained from the control treatment (772 and 3134 kg ha-1). The study conducted revealed that along with optimum date of sowing, spraying micronutrients especially a mixture of [email protected] % and [email protected] % could also bring in change of phenology to some extent. This may help in better accumulation of photosynthate hence, improving the yield responses of lentil.

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