Accumulation Of Growing Degree Days Research Articles

Northern Annular Mode Effects on the Land Surface Phenologies of Northern Eurasia

Abstract Land surface phenology (LSP) is the spatiotemporal development of the vegetated land surface as revealed by synoptic sensors. Modeling LSP across northern Eurasia reveals the magnitude, significance, and spatial pattern of the influence of the northern annular mode. Here the authors fit simple LSP models to two normalized difference vegetation index (NDVI) datasets and calculate the Spearman rank correlations to link the start of the observed growing season (SOS) and the timing of the peak NDVI with the North Atlantic Oscillation (NAO) and Arctic Oscillation (AO) indices. The relationships between the northern annular mode and weather station data, accumulated precipitation derived from the Climate Prediction Center (CPC) Merged Analysis of Precipitation (CMAP) dataset, accumulated growing degree-days (AGDDs) derived from the NCEP–Department of Energy Atmospheric Model Intercomparison Project (AMIP-II) reanalysis, and the number of snow days from the National Snow and Ice Data Center are investigated. The analyses confirm strong relationships between the temporal behavior of temperature and precipitation and large-scale climatic variability across Eurasia. The authors find widespread influence of the northern annular mode (NAM) on the land surface phenologies across northern Eurasia affecting 200–300 Mha. The tundra ecoregions were especially impacted with significant results for about a quarter of the biome. The influence of the AO was also extensive (>130 Mha) for the boreal forests. The AO appears to affect the Asian part of northern Eurasia more strongly than the NAO, especially for the NDVI peak position as a function of AGDD. Significant responses of vegetation timing to NAO and AO in northeastern Russia have not been as well documented as the seasonal advancement in Europe. The two Advanced Very High Resolution Radiometer NDVI datasets yield fields of LSP model parameter estimates that are more similar in dates of peak position than in dates for SOS and more similar for AO than for NAO. As a result, the authors conclude that peak position appears to be a more robust characteristic of land surface phenology than SOS to link vegetation dynamics to variability and change in regional and global climates.

Monitoring start of season in Alaska with GLOBE, AVHRR, and MODIS data

This work evaluates whether continuity between Advanced Very High Resolution Radiometer (AVHRR) and Moderate Resolution Imaging Spectroradiometer (MODIS) normalized difference vegetation index (NDVI) is achievable for monitoring phenological changes in Alaska. This work also evaluates whether NDVI can detect changes in start of the growing season (SOS) in this region. Six quadratic regression models with NDVI as a function of accumulated growing degree days (AGDD) were developed from 2001 through 2004 AVHRR and MODIS NDVI data sets for urban, mixed, and forested land covers. Model parameters determined NDVI values for start of the observational period as well as peak and length of the growing season. NDVI values for start of the growing season were determined from the model equations and field observations of SOS made by GLOBE students and researchers at University of Alaska Fairbanks. AGDD was computed from daily air temperature. AVHRR and MODIS models were significantly different from one another with differences in the start of the observational season as well as start, peak, and length of the growing season. Furthermore, AGDD for SOS was significantly lower during the 1990s than the 1980s. NDVI values at SOS did not detect this change. There are limitations with using NDVI to monitor phenological changes in these regions because of snow, the large extent of conifers, and clouds, which restrict the composite period. In addition, differing processing and spectral characteristics restrict continuity between AVHRR and MODIS NDVI data sets.

Emergence Timing and Recruitment of Volunteer Spring Wheat

With the recent interest in genetically engineered (GE) wheat and the commercialization of novel-trait imidazolinone herbicide-resistant wheat in North America, volunteer wheat as a weed has also been the subject of renewed interest, specifically, its recruitment and persistence in annual cropping systems. The recruitment of seed from a wheat seedbank established the previous autumn was monitored in a flax crop at two field sites in southern Manitoba, Canada, in 2003 and 2004. Seeds of eight Canadian Western Hard Red spring wheat cultivars, which exhibit a range of preharvest sprouting-resistance characteristics, were broadcast and incorporated into the soil in the autumn at 500 seeds m−2. Tillage treatments consisted of autumn tillage only, and autumn and spring tillage. Recruitment the following spring occurred very early in terms of accumulated growing–degree days (base temperature of 0 C) but expressed as a proportion of total seeds broadcast was low and variable. Total cumulative emergence of wheat over all 4 site yr ranged from 0.9 to 13.1%, with an overall average of 4.3%. There was no relationship between preharvest sprouting-resistance characteristics and recruitment proportion, and no significant influence of tillage treatment on wheat recruitment. Wheat seed that did not recruit was rapidly degraded in the soil and did not persist for more than 12 mo. However, some emerged volunteer wheat plants escaped all control measures normally used in establishing and growing a typical flax crop, and these escaped volunteer wheat plants set viable seed. Therefore, results of this study indicate that efforts and attention should be directed toward achieving very high levels of volunteer wheat control in subsequent rotational crops and that reseeding by escaped volunteer wheat plants may be a more important persistence mechanism for spring wheat than multiyear soil seedbank persistence.

Maturation curves and degree-days accumulation for fruits of 'Folha Murcha' orange trees

The effect of thermal summation on orange fruit growth on different rootstocks has not been studied for the State of Paraná, Brazil. This research evaluated the growth of fruits by means of maturation curves, and quantified the growing degree-days (GDD) accumulation required for fruit maturation in 'Folha Murcha' orange trees budded on 'Rangpur' lime, 'Volkamer' lemon, 'Sunki' mandarin, and 'Cleopatra' mandarin, in Paranavaí and Londrina, PR. In both locations and all rootstocks, the fruits showed evolution in total soluble solids (TSS) content in relation to GDD accumulation, with a quadratic tendency of curve fitting; total titratable acidity (TTA) had an inverse quadratic fitting, and the (TSS/TTA) ratio showed a positive linear regression. Fruits in Paranavaí presented a higher development rate towards maturity than those in Londrina, for all rootstocks. The advancing of the initial maturation stage of fruits in Paranavaí in relation to those in Londrina occurred in the following descending order: 'Volkamer' lemon (92 days), 'Cleopatra' mandarin (81 days), 'Sunki' mandarin (79 days), 'Rangpur' lime (77 days). In Londrina, trees on 'Rangpur' lime and 'Volkamer' lemon were ready for harvest 8 and 15 days before those on the 'Cleopatra' and 'Sunki' mandarins, respectively. In Paranavaí, the beginning of fruit maturation in trees on 'Volkamer' lemon occurred 15, 19, and 28 days earlier than on 'Rangpur' lime, 'Cleopatra' mandarin, and 'Sunki' mandarin, respectively. Considering 12.8ºC as the lower base temperature, the thermal sum for fruit growth and maturation of 'Folha Murcha' orange ranged from 4,462 to 5,090 GDD.

Predicting Nitrogen Content in the Northern Mixed-Grass Prairie

Forage quality and quantity are important factors affecting livestock production from grazing lands. ‘‘Greenness’’ has been proposed as an indicator of herbage quality in semiarid environments, particularly nitrogen (N) content. The objective of this study was to assess the potential of estimating N content of forage using dead:green ratios and accumulated growing-degreedays (AGDD). Standing crop samples were collected April through October over 3 years from each of 3 replicated grazing regimes on a silty range site in eastern Montana. Samples were sorted into live, current dead, and old dead components, then dried, ground, and analyzed for N content. The AGDD for base temperature 458F (7.28C) was calculated from National Oceanic and Atmospheric Administration (NOAA) reported monthly average temperatures for Miles City. An equation to predict percent N in the total standing crop from percent dead forage and AGDD was developed using multiple linear regression. This equation accounted for 75.9% of variation in percent N, and prediction error variance was 0.026. To validate this equation, data were obtained from samples collected from April through September in an independent study of 8 areas on silty and claypan range sites grazed during autumn and winter. Samples from these sites were treated and analyzed in the same manner as those used to develop the equation. The developed equation was used to predict percent N for the validation data. The resulting correlation between predicted and actual values was 0.79. The regression coefficient for actual values on predicted values was 0.995 6 0.125. The intercept did not differ from 0.0 (P ¼ 0.22), and prediction error variance was 0.042. This equation has utility for predicting N level of forage from Northern Great Plains rangelands.

Predicting Nitrogen Content in the Northern Mixed-Grass Prairie

Forage quality and quantity are important factors affecting livestock production from grazing lands. ‘‘Greenness’’ has been proposed as an indicator of herbage quality in semiarid environments, particularly nitrogen (N) content. The objective of this study was to assess the potential of estimating N content of forage using dead:green ratios and accumulated growing-degree- days (AGDD). Standing crop samples were collected April through October over 3 years from each of 3 replicated grazing regimes on a silty range site in eastern Montana. Samples were sorted into live, current dead, and old dead components, then dried, ground, and analyzed for N content. The AGDD for base temperature 45 degreesF (7.2 degreesC) was calculated from National Oceanic and Atmospheric Administration (NOAA) reported monthly average temperatures for Miles City. An equation to predict percent N in the total standing crop from percent dead forage and AGDD was developed using multiple linear regression. This equation accounted for 75.9% of variation in percent N, and prediction error variance was 0.026. To validate this equation, data were obtained from samples collected from April through September in an independent study of 8 areas on silty and clay- pan range sites grazed during autumn and winter. Samples from these sites were treated and analyzed in the same manner as those used to develop the equation. The developed equation was used to predict percent N for the validation data. The resulting correlation between predicted and actual values was 0.79. The regression coefficient for actual values on predicted values was 0.995 +/- 0.125. The intercept did not differ from 0.0 (P = 0.22), and prediction error variance was 0.042. This equation has utility for predicting N level of forage from Northern Great Plains rangelands.

Land surface phenology, climatic variation, and institutional change: Analyzing agricultural land cover change in Kazakhstan

Kazakhstan is the second largest country to emerge from the collapse of the Soviet Union. Consequent to the abrupt institutional changes surrounding the disintegration of the Soviet Union in the early 1990s, Kazakhstan has reportedly undergone extensive land cover/land use change. Were the institutional changes sufficiently great to affect land surface phenology at spatial resolutions and extents relevant to mesoscale meteorological models? To explore this question, we used the NDVI time series (1985–1988 and 1995–1999) from the Pathfinder Advanced Very High Resolution Radiometer (AVHRR) Land (PAL) dataset, which consists of 10 days maximum NDVI composites at a spatial resolution of 8 km. Daily minimum and maximum temperatures were extracted from the NCEP Reanalysis Project and 10 days composites of accumulated growing degree-days (AGDD) were produced. We selected for intensive study seven agricultural areas ranging from regions with rain-fed spring wheat cultivation in the north to regions of irrigated cotton and rice in the south. We applied three distinct but complementary statistical analyses: (1) nonparametric testing of sample distributions; (2) simple time series analysis to evaluate trends and seasonality; and (3) simple regression models describing NDVI as a quadratic function of AGDD. The irrigated areas displayed different temporal developments of NDVI between 1985–1988 and 1995–1999. As the temperature regime between the two periods was not significantly different, we conclude that observed differences in the temporal development of NDVI resulted from changes in agricultural practices. In the north, the temperature regime was also comparable for both periods. Based on extant socioeconomic studies and our model analyses, we conclude that the changes in the observed land surface phenology in the northern regions are caused by large increases in fallow land dominated by weedy species and by grasslands under reduced grazing pressure. Using multiple lines of evidence allowed us to build a case of whether differences in land surface phenology were mostly the result of anthropogenic influences or interannual climatic fluctuations.

Yields and Economics of High Tunnels for Production of Warm-season Vegetable Crops

Crop development rates, yields and production economics for muskmelon (Cucumis melo), pepper (Capsicum annuum) and tomato (Lycopersicon lycopersicum) grown in high tunnels [4.3 m wid × 2.5 m high × 29 m long (14 × 8 × 96 ft)] were compared to standard low tunnels over several cropping seasons in a temperate production area. The polyethylene-covered high tunnels protect several rows of crop for the duration of the cropping season. Air temperatures in the high tunnels were controlled by raising the sides of the tunnel. Low tunnels cover only a single row and must be removed soon after the crop is established to prevent overcrowding or overheating. When the low tunnels were in place, rates of accumulation of growing-degree days (GDDs) and early crop growth were comparable in the two tunnel systems. However, once the low tunnels were removed, the accumulation of GDDs in the high tunnels exceeded the standard system. The crops in the high tunnels matured 1 to 2 weeks earlier and produced substantially greater fruit yields before frost than in the low tunnel treatments. The high tunnels provided little frost protection and were of limited utility for extension of the growing season. The high tunnels were much more costly to purchase and construct than the low tunnels but were durable enough to be used for multiple cropping seasons. Based on wholesale commodity prices, it would take 2 to 5 years for the enhanced gross returns obtained with the high tunnels to cover their higher capital costs.

Introduction of multipurpose agro-industrial crop quinoa (Chenopodium quinoa) in western Himalayas

Two accessions of quinoa (Chenopodium quinoa Willd.) were introduced in mid-hills of the western Himalayas for the first time during 2016 and an experiment was conducted at Palampur, Himachal Pradesh, to study the ef- fect of sowing time on growth, quality parameters and yield. The crop took 129 to 159 days for maturity and per- formed well under mid-hill conditions. Accumulated growing degree-days (AGDD) ranged from 512 to 2,432, ac- cumulated photothermal units (APTU) from 5,595 to 31,705 and accumulated helio-thermal units (AHTU) from 3,942 to 18,183 during seed sowing to maturity, respectively. Agrometeorological indices showed a positive corre- lation with growth and yield attributes. Significantly higher plant height was recorded on 30 January sown crop. The highest seed yield was recorded when the crop was sown on 30 January, being 10.48% and 19.63% higher than those sown on 15 February and 15 January, respectively. Protein content in quinoa seed ranged from 18.1 to 21.6% and was significantly higher when the crop was sown on 15 February. Carbohydrate concentration ranged from 65.3 to 67.6% and it was significantly higher in IHBT/Q2 accession. Other nutrients were present in permis- sible limits. The results showed that the nutritional potential of quinoa seeds is a good source of protein and min- erals, and quinoa can be grown as successful crop under mid-hills of the western Himalayas.

Effect of date of planting and harvesting schedule on heat-unit accumulation and biomass production in Japanese mint (Mentha arvensis)

The present investigation was carried out during the spring season of 2010 and 2011 at Ludhiana, Punjab, to study the effect of heat-unit accumulation on herb and oil productivity of Japanese mint (Mentha arvensis L.) under different dates of planting and harvesting schedules. The field experiment was laid out in split-plot design keeping 4 dates of planting 1 January, 15 January, 30 January and 15 February in main plots and 3 harvesting schedules (120, 135 and 150 days after planting) in subplots. Japanese mint planted on 15 February recorded the maximum fresh-herb and oil yields, which were statistically at par with that planted on 30 January, but were significantly higher than 15 January and 1 January plantings. The crop planted on 30 January and 15 February accumulated 456 and 624 and 222 and 390 units higher growing degree-days (GDD) than 1 January and 15 January planted crop respectively. The fresh-herb and oil yield of mint increased successively and significantly with delay in har- vesting from 120 to 150 days after planting (DAP). The growing degree-days (GDD), photothermal units (PTU) and heliothermal units (HTU) accumulation were 649, 8,866 and 5,275 and 322, 4,480 and 2,548 units higher in crop harvested at 150 DAP than that harvested 120 and 135 DAP respectively. The interaction effects revealed that crop planted on 15 February and harvested at 150 DAP gave the maximum biomass and oil yield, which were sta- tistically at par with that planted on 30 January and harvested at 150 days after planting, but was significantly bet- ter than all other combination because of higher accumulation of GDD, HTU and PTU. The multiple regression model was found to be well fit with P=0.0006, which revealed that fresh- herb yield of mint was significantly and positively correlated with GDD, HTU and PTU at multiple correlation value of 0.9636.

Application of Systemic Insecticides in Relation to Boxwood Leafminer's Life History

We describe the life cycle of boxwood leafminer (Monarthropalpus jlavus) in the mid-Atlantic region of the United States in relation to growing degreeday accumulations. In addition, the efficacy of three systemic insecticides (avermectin, imidacloprid, and acephate) for control of the boxwood leafminer were evaluated. Avermectin and imidacloprid applied at adult flight provided excellent control. Imidacloprid applied in the summer when larvae were present in leaves gave good control of larvae. Avermectin and acephate were ineffective when applied in the summer.

Phenology and Tiller Characteristics of Big Bluestem and Switchgrass Cultivars in a Short Growing Season Area

AbstractWarm‐season grasses are increasingly being cultivated in North America for summer forage and biomass production. The cooler temperatures and shorter growing seasons typical of Canadian production areas, are major limiting factors to warm‐season grass production in these areas. This research assessed the morphological development and relationship of growing degree‐days (GDD) to plant morphology and tiller characteristics in nine cultivars of switchgrass (Panicum virgatum L.; Blackwell, Cave‐in‐Rock, Dakota, Forestburg, Pathfinder, Shelter, Sunburst, ND3743, and New Jersey 50) and in ‘Niagara’ big bluestem (Andropogon gerardii Vitman). The study was conducted for three years on a St. Bernard sandy clay loam (Typic Hapludalf) in southwestern Quebec. Stand cover, plant morphology, tiller number, height, and diameter, and leaf number per tiller were all assessed during the season. All entries persisted through the three years of the study and showed increases in tiller number (from an average of 565 to 683 m−2) from one year to the next. Dakota, Cave‐in‐Rock, and Shelter switchgrass had the highest ground cover ratings after three years (85, 85, and 84%, respectively). Dakota, ND3743, and Forestburg were early maturing; New Jersey 50 was the latest in maturity. Niagara big bluestem had the tallest tillers (183 cm) and largest rates of increase in height (2.8 cm d‐1), followed by Cave‐in‐Rock (2.0 cm d−1) and Blackwell (1.9 cm d−1). The shortest tillers were recorded for Dakota (111 cm) and ND3743 (118 cm). Changes in leaf number per tiller with GDD were best described by quadratic regression models (r2 = 0.80‐0.97). These models were stable over two years. Cultivars varied in the number of GDD required for maximum number of leaves per tiller, with later‐maturing cultivars generally requiring greater GDD accumulation. These data indicate that warmseason grasses can be grown successfully in eastern Canada.

Standardization of weekly growing degree day accumulations based on differences in temperature observation time and method

Efforts to develop comparable growing degree day (GDD) accumulations across the US-Canadian border have revealed significant anomalies resulting from differences in observing times among US stations and reporting practices between US and Canadian stations. Simulations using hourly temperature data indicate that the period required to reach a given GDD threshold value during a growing season often varies by 2 weeks or more solely because of observation time differences. Previous work on methods to adjust such biases has concentrated on seasonal totals and long-term averages. In this study, empirical methods are developed to standardize weekly GDD accumulations to a common observing time. Hourly data for a 10 year period from five northeastern United States stations are used in the development of the adjustment procedure. However, only daily maximum and minimum temperatures are needed to implement the adjustment scheme. Different weekly adjustment factors are used for each month from March through November. In addition, the weekly adjustment factors are decreased in magnitude during individual spring and autumn weeks in which fewer than 25 degree days (13.9°C GDD) accumulate. Correction factors are also reduced during summer weeks which exhibit minimal day-to-day variation in temperature. An additional adjustment is applied to observations taken in the late afternoon and evening to ensure that the maximum temperature observed at these stations has occurred on the same day as that reported by morning observing sites. Validation trials using data from six independent stations indicate that average weekly differences of as much as 10 GDD (5.6°C GDD) are reduced to less than 1 GDD (0.6°C GDD). After applying the standardization procedures, GDD values based on different observation times and the Canadian observation practice accumulate at similar rates.

Apical Development of Spring Barley under Field Conditions in Northeastern North America

Although the apical development of barley (Hordeum vulgare L.) has been extensively researched, a complete description of spring barley apical development stages has not been published for continental North American field conditions. This study determined the timing and duration of the apical development stages, and the pattern and dynamics of spikelet primordium initiation. Data were collected for two barley cultivars for three successive seasons in eastern Canada. From the seedling stage to anthesis, apical development and the total number of primordia on the mainstem were monitored, and both were related to days after seeding (DAS) and to accumulated growing degree‐days (AGDD). The mainstem apex reached the double ridge stage 22 to 24 DAS (320–340 AGDD), awn initiation 40 to 42 DAS (≈650 AGDD), and anthesis 50 to 56 DAS (860–940 AGDD), with some variations among cultivars and years. Nine mainstem leaf primordia were initiated by 16 DAS. Spikelet primordium initiation was completed by awn initiation when 30 to 35 primordia had been formed. The data provide a description of barley apical development stages and indicate that spikelet primoridum production (i) occurs at a variable rate, (ii) is largely a function of thermal time, although genotype and climatic factors have some effect, and (iii) is related to time or thermal time in a curvilinear, rather than a linear fashion.

Estimation and evaluation of winter wheat phenology in the central Great Plains

Crop modeling and management requires accurate prediction of crop phenology. Phenology data for winter wheat ( Triticum aestivum L.) were collected from seven sites in the central Great Plains for several years to relate phenological stages to environmental and cultural factors, and to provide needed phenology data for the central Great Plains. Number of calendar days ( ND), growing degree-days ( GDD), and photothermal units ( PTU) were calculated for emergence (E), tiller initiation (TI), dormancy end (DE), jointing (J), heading (H), kernel in milk (KM), kernel in hard dough (KD), and maturity (M) using the Feekes growth scale for the main stem. Nine base temperatures (−2, 0, 1, 2, 3, 4, 5, 7, and 9°C) were used when accumulating GDD and PTU. Mean daily temperatures of 20, 25, and 30°C were used for upper thresholds. Accumulation of GDD, PTU and ND were calculated from planting date (S), E, and 1 January to the growth stage and from one growth stage to the next. Model sensitivity to soil water, cultivar, seeding rates, row spacing, rotation, and fertilizer were examined. The lower the base temperature for a model, the lower the root mean square error ( RMSE) when beginning accumulation from S, E or 1 January, with −2°C the best except for DE, KD, and M where higher base temperatures tended to have lower RMSE. As M was approached, the 25°C upper threshold tended to do better than 20°C. Little difference was found between 25 and 30°C upper thresholds. The best model for predicting a stage varied, with ND the best for E through J. From H through M, PTU models had the lowest RMSE. Normally, GDD and PTU models beginning accumulation from 1 January outperformed models beginning accumulation from S or E. The GDD or PTU related to availability of soil water showed a parabolic relationship (concave downward) beginning at J and becoming more platykurtic as M was approached. Significant sensitivity to cultivar and row spacing/rotation was found, with occasional sensitivity by various model types found to fertilizer and planting date.