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

Comparison of grain moisture vs. visual observation in selection for early maturity in barley

2000 ◽  
Vol 80 (2) ◽  
pp. 327-329
Author(s):  
S. M. Dofing
Keyword(s):  
Correlation Coefficients ◽  
Visual Observation ◽  
Growing Degree Days ◽  
Degree Days ◽  
Hordeum Vulgare L ◽  
Early Maturity ◽  
Barley Cultivars ◽  
Harvest Dates ◽  
Grain Moisture ◽  
Days To Maturity

The purpose of this research was to compare assessments of maturity in barley (Hordeum vulgare L.) using growing degree days to maturity based on visual head color and percent grain moisture. Twelve barley cultivars were evaluated for 3 yr at Palmer, Alaska, using three harvest dates. Phenotypic and environmental correlation coefficients between growing degree days to maturity and grain moisture at harvest were high, and tended to be highest at earlier harvest dates. Key words: Barley, early maturity, selection

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.

Growth, phenology and thermal indices of mungbean as influenced by sowing time, varieties and planting geometry

2015 ◽  
Vol 49 (5) ◽  
Author(s):  
Harinder Singh ◽  
Guriqbal Singh
Keyword(s):  
Field Experiment ◽  
Dry Matter ◽  
Growing Degree Days ◽  
Dry Matter Accumulation ◽  
Degree Days ◽  
Thermal Indices ◽  
Higher Plant ◽  
Phenological Stages ◽  
Sowing Time ◽  
Planting Geometry

A field experiment was conducted during <italic>kharif</italic> 2012 to assess the effects of sowing time (1, 10, 20, and 30 July) and planting geometry (30 cm × 10 cm and 22.5 cm × 10 cm) on the growth, phenology and thermal indices of mungbean varieties (PAU 911 and ML 818). The crop sown on 1 July recorded higher plant height and dry matter accumulation (DMA) and required higher thermal indices <italic>viz</italic>. accumulated growing degree days (AGDD), accumulated photothermal units (APTU) and accumulated heliothermal units (AHTU) to complete various phenological stages as compared to all other sowing times. Mungbean variety PAU 911 took lesser days to complete various phenological stages and required lesser AGDD, AHTU and APTU as compared to ML 818. Plants in planting geometry of 30 cm ×10 cm recorded significantly higher DMA and attained significantly higher AGDD, AHTU and APTU as compared to in 22.5 cm ×10 cm geometry.

Potential impacts of climate change on corn, soybeans and barley yields in Atlantic Canada

2005 ◽  
Vol 85 (2) ◽  
pp. 345-357 ◽  
Author(s):  
A. Bootsma ◽  
S. Gameda ◽  
D. W. McKenney
Keyword(s):  
Climate Change ◽  
Direct Effect ◽  
Crop Production ◽  
Field Trials ◽  
Growing Degree Days ◽  
Degree Days ◽  
Atlantic Region ◽  
Water Deficits ◽  
Heat Units ◽  
Impacts Of Climate Change

In this paper, relationships between agroclimatic indices and average yields of grain corn (Zea mays L.), soybeans (Glycine max L. Merr.) and barley (Hordeum vulgare L.) in field trials conducted in eastern Canada are explored and then used to estimate potential impacts of climate change scenarios on anticipated average yields and total production of these commodities for the Atlantic region for the 2040 to 2069 period. Average yields of grain corn and soybeans were highly correlated (R2 = 0.86 and 0.74, respectively) with average available crop heat units (CHU), with yields increasing by about 0.006 t ha-1 CHU-1 for corn and 0.0013 t ha-1 CHU-1 for soybeans. The explained variance was not improved significantly when water deficit (DEFICIT) was included as an independent variable in regression. Correlations between average yields of barley and effective growing degree-days (EGDD) were low (R2 ≤ 0.26) and negative, i.e., there was a tendency for slightly lower yields at higher EGDD values. Including a second-order polynomial for DEFICIT in the regression increased the R2 to ≥ 0.58, indicating a tendency for lower barley yields in areas with high water deficits and with water surpluses. Based on a range of available heat units projected by multiple General Circulation Model (GCM) experiments, average yields achievable in field trials could increase by about 2.6 to 7.5 t ha-1 (40 to 115%) for corn, and by 0.6 to 1.5 t ha-1 (21 to 50%) for soybeans by 2040 to 2069, not including the direct effect of increased atmospheric CO2 concentrations, advances in plant breeding and crop production practices or changes in impacts of weeds, insects and diseases on yield. Anticipated reductions in barley yields are likely to be more than offset by the direct effect of increased CO2 concentrations. As a result of changes in potential yields, there will likely be significant shifts away from production of barley to high-energy and high-protein crops (corn and soybeans) that are better adapted to the warmer climate. However, barley and other small grain cereals will likely remain as important crops as they are very suited for rotation with potatoes. There is a need to evaluate the potential environmental impacts of these possible shifts in crop production, particularly with respect to soil erosion in the region. Key words: Crop heat units, growing degree-days, water deficits, crop yields, climate change, Atlantic region

Relationships among growing degree-days, tenderness, other harvest attributes and market value of processing pea (Pisum sativum L.) cultivars grown in Quebec

2006 ◽  
Vol 86 (2) ◽  
pp. 525-537 ◽  
Author(s):  
Edith Fallon, Nicolas Tremblay ◽  
Yves Desjardins
Keyword(s):  
Moisture Content ◽  
Size Distribution ◽  
Seed Size ◽  
Growing Degree Days ◽  
Harvest Time ◽  
Degree Days ◽  
Fresh Matter ◽  
Yield And Quality ◽  
Grain Moisture ◽  
The Relationship

In Quebec, grower income from processing peas is a function of yield and tenderometer reading. If peas are harvested early, the yield is poor, but the overall quality is superior, as indicated by lower tenderometer readings. Later harvests result in g reater yields but reduced quality (higher tenderometer readings). A better understanding of the relationship between harvest time, yield and quality is needed. In this study, the relationships between yield, tenderometer readings, size distribution and grain moisture content were examined as a function of growing degree-days (GDD) and production year for pea cultivars of different seed size categories. Yield and harvest attributes (tenderometer readings, seed size distribution and moisture content) were highly season dependent and their rates of change over the course of the harvest period also varied with the cultivar and year. Quality declined rapidly once the crop reached optimal maturity, while yield increased in a less predictable manner. Consequently, it was difficult to identify a harvest time that would consistently maximize grower returns. The highest income was generally not obtained at the optimal tenderometer readings presently used by the industry. Key words: Maturity, harvest date, climate, fresh matter yield, tenderometer, pea size

Investigating morpho-physiological traits and agro-meteorological indices in green gram [Vigna radiata L. Wilczek] for terminal heat tolerance

2016 ◽  
Author(s):  
Chandan Kumar ◽  
S. B. Mishra ◽  
Nilanjaya . ◽  
Chandra Mohan Singh
Keyword(s):  
Heat Stress ◽  
Seed Yield ◽  
Stress Condition ◽  
Growing Degree Days ◽  
Degree Days ◽  
Relative Temperature ◽  
Thermal Index ◽  
Heat Stress Condition ◽  
Use Efficiency ◽  
Temperature Depression

Forty genotypes of greengram were studied to ascertain the genetic variability and trait association among some important morpho-physiological traits and agro-meterological indices under heat stress condition. The results indicated that both GCV and PCV estimates were high for photo thermal index, heat use efficiency and seed yield. High heritability coupled with moderate genetic advance as per cent of mean was recorded for photo-thermal unit and relative temperature depression indicated that involvement of both additive and non-additive type of gene action and possibilities of effective selection for improvement of these traits. Seed yield showed significant and positive association with days to maturity, growing degree days, relative temperature depression and heat use efficiency. Based on variability, association and path analysis; heat use efficiency, maturity, photo thermal index and growing degree days were found most contributing indices/ traits should be considered as selection criteria for discrimination of outstanding greengram genotypes under heat stress condition.

Estimating Corn Growth, Yield, and Grain Moisture from Air Growing Degree Days and Residue Cover 1

1987 ◽  
Vol 79 (1) ◽  
pp. 53-60 ◽  
Author(s):  
J. B. Swan ◽  
E. C. Schneider ◽  
J. F. Moncrief ◽  
W. H. Paulson ◽  
A. E. Peterson
Keyword(s):  
Growth Yield ◽  
Growing Degree Days ◽  
Degree Days ◽  
Grain Moisture

Impacts of potential climate change on selected agroclimatic indices in Atlantic Canada

2005 ◽  
Vol 85 (2) ◽  
pp. 329-343 ◽  
Author(s):  
A. Bootsma ◽  
S. Gameda and D.W. McKenney
Keyword(s):  
Climate Change ◽  
Statistical Downscaling ◽  
Growing Degree Days ◽  
Climate Change Scenarios ◽  
Degree Days ◽  
Atlantic Region ◽  
Water Deficits ◽  
Heat Units ◽  
Agricultural Areas ◽  
The Impact

Agroclimatic indices (heat units and water deficits) were determined for the Atlantic region of Canada for a baseline climate (1961 to 1990 period) and for two future time periods (2010 to 2039 and 2040 to 2069). Climate scenarios for the future periods were primarily based on outputs from the Canadian General Circulation Model (GCM) that included the effects of aerosols (CGCMI-A), but variability introduced by multiple GCM experiments was also examined. Climatic data for all three periods were interpolated to a grid of about 10 to 15 km. Agroclimatic indices were computed and mapped based on the gridded data. Based on CGCMI-A scenarios interpolated to the fine grid, average crop heat units (CHU) would increase by 300 to 500 CHU for the 2010 to 2039 period and by 500 to 700 CHU for the 2040 to 2069 period in the main agricultural areas of the Atlantic region. However, increases in CHU for the 2040 to 2069 period typically varied from 450 to 1650 units in these regions when variability among GCM experiments was considered, resulting in a projected range of 2650 to 4000 available CHU. Effective growing degree-days above 5°C (EGDD) typically increased by about 400 units for the 2040 to 2069 period in the main agricultural areas, resulting in available EGDD from 1800 to over 2000 units. Uncertainty introduced by multiple GCMs increased the range from 1700 to 2700 EGDD. A decrease in heat units (cooling) is anticipated along part of the coast of Labrador. Anticipated changes in water deficits (DEFICIT), defined as the amount by which potential evapotranspiration exceeded precipitation over the growing season, typically ranged from +50 to −50 mm for both periods, but this range widened from +50 to −100 mm when variability among GCM experiments was considered. The greatest increases in deficits were expected in the central region of New Brunswick for the 2040 to 2069 period. Our interpolation procedures estimated mean winter and summer temperature changes that were 1.4°C on average lower than a statistical downscaling procedure (SDSM) for four locations. Increases in precipitation during summer and autumn averaged 20% less than SDSM. During periods when SDSM estimated relatively small changes in temperature or precipitation, our interpolation procedure tended to produce changes that were larger than SDSM. Additional investigations would be beneficial that explore the impact of a range of scenarios from other GCM models, other downscaling methods and the potential effects of change in climate variability on these agroclimatic indices. Potential impacts of these changes on crop yields and production in the region also need to be explored. Key words: Crop heat units, effective growing degree-days, water deficits, climate change scenarios, statistical downscaling, spatial interpolation

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

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