Long term (100 yr) climatic trends for agriculture at selected locations in Canada

Bootsma, A.

doi:10.1007/bf01094009

Cited by 73 publications

(63 citation statements)

References 18 publications

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“…Walther and Linderholm, 2006). When defining the start and the end of the GS, either the timing of the last frost in spring and the first frost in autumn or threshold temperatures in a predefined number of days are used (Skaggs and Baker, 1985;Bootsma, 1994;Carter, 1998;Frich et al, 2002;Jones et al, 2002;Robeson, 2002, Schwartz andChen, 2002;Schwartz et al, 2006). In a study of GS parameters in the Greater Baltic Area, Walther and Linderholm (2006) noted significant differences in the results depending on the index used.…”

Section: Defining the Gsmentioning

confidence: 99%

Trends of the thermal growing season in China, 1951–2007

Song

Linderholm

Chen

et al. 2009

Intl Journal of Climatology

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Observed 20th century changes in the length of the growing season (GS) across the Northern Hemisphere have been linked to increasing temperatures, associated with global warming. Past studies of GS changes in China have largely been based on phenological observations and satellite data, and little attention has been paid to changes in starting and ending dates of GS. Here we examine changes in the thermal GS over China from 1951 to 2007 based on observed daily surface air temperature. Using five indices, trends of three GS parameters, start, end and length, were determined at 114 high-quality stations over China. Our results show large spatial and temporal differences in the GS parameters in China, where the most prominent changes have occurred in northern China relative to southern China. On average, from 1951 to 2007 the GS has been extended by 2.3 days/decade in northern China where most of these changes is due to an earlier onset of the GS in spring (−1.7 days/decade). In southern China, there is an average increase of GS by 1.3 days/decade with 0.6 days/decade earlier onsets in spring. Furthermore, most stations showing significant trends of GS changes are located in northern China. An extended GS in northern China indicates improved agricultural conditions due to warmer and longer GS. However, this effect may be counteracted by changes in the precipitation pattern.

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Section: Defining the Gsmentioning

confidence: 99%

Trends of the thermal growing season in China, 1951–2007

Song

Linderholm

Chen

et al. 2009

Intl Journal of Climatology

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“…Thus, if not only mean trends, but also time series of phenological phases are to be approximated from climatological data, then it is recommended not to rely on single-value thresholds, but on integrating, smoothing measures (e.g. Bootsma, 1994).…”

Section: Comparison Of the Climatological And Phenological Growing Sementioning

confidence: 99%

Variations of the climatological growing season (1951–2000) in Germany compared with other countries

Menzel

Jakobi

Ahas

et al. 2003

Intl Journal of Climatology

169

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We analyse how variations in the climatological growing season, defined by single-value thresholds of daily minimum and mean air temperature, mirror recent changes in plant phenological phases. In Germany 41 climate stations), the dates of last spring frost T min < 0°C (<−3°C and <−5°C) advance by 0.24 (0.23 and 0.32) days per year on average, and the first day when the daily mean temperature constantly exceeds 5°C (7°C and 10°C) advances by 0.13 (0.21 and 0.09) days per year. The respective autumn dates are delayed up to 0.25 days per year; in total, the climatological growing season is lengthened by 0.11 to 0.49 days per year, depending on the criterion analysed. However, a certain station-to-station variability is displayed. Mean trends of phenological phases correspond well to those measures of the climatological growing season having similar seasonal occurrence. Thus, for example, the extension of the growing seasons of trees (up to 0.22 days per year) averages the lengthening of the period where the daily mean temperature constantly exceeds 5°C (0.23 days per year). However, the greatest changes result for the lengthening of the frost-free period (0.49 days per year) due to the observed stronger increase in daily minimum rather than maximum temperatures. Consequently, trees may not take advantage of the frost-free season as before, but may profit from a reduced risk of damage by late spring frosts.A parallel evaluation of trends in the climatological growing season in other European countries (Austria, Switzerland, Estonia) supports this finding of a stronger lengthening of the frost-free period than that of the growing season based on daily mean air temperature. The mean lengthening of the frost-free period of 0.50 days per year in Austria and Switzerland (1951-99, 18 stations <950 m a.s.l.) and 0.34 days per year in Estonia (1951Estonia ( -2000 is quite similar to that in Germany. The lengthening of the growing season (T mean ≥ 7°C) in Austria and Switzerland (0.39 days per year) also approximates the respective result for Germany (0.36 days per year). However, in several cases, the trends increase with altitude (up to 500-900 m a.s.l.), but at high-elevation climate stations (>950 m a.s.l.) weaker trends are again generally observed.

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“…Bootsma (1994) reported no appreciable changes in growing season rainfall and overwinter snowfall at Indian Head, located in the Thin Black soil zone, during the period 1891 to 1989. Staple and Lehane (1952) reported precipitation data from 10 locations in southwestern Saskatchewan for the period 1937 to 1950, showing that, on average, precipitation received during the approximate 20-mo summer fallow period was 475 mm.…”

Section: Mots Clé Smentioning

confidence: 94%

Quantifying soil water conservation in the semiarid region of Saskatchewan, Canada: Effect of fallow frequency and N fertilizer

Jong¹,

Campbell²,

Zentner³

et al. 2008

Can. J. Soil. Sci.

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Soil water is the most limiting factor influencing crop production in the semiarid prairies. The effects of fallow frequency and nitrogen (N) fertilization on soil water conservation were quantified for a 40-yr (1967–2006) field experiment conducted on a medium textured Orthic Brown Chernozem (aridic haploboroll) in semiarid southwestern Saskatchewan, in which soil water contents were measured each year in early spring (generally a week prior to seeding), shortly after harvest, and again just prior to freeze-up in the fall. The three treatments examined were continuous spring wheat (Triticum aestivum L.) (Cont W) and fallow-wheat (F-W), each receiving recommended rates of N and P fertilizer, and Cont W receiving only P. On average, 36% of the precipitation received during the fall and winter months for Cont W (N + P) was conserved in the soil. In the summer fallow system [F-W (N + P)] a greater proportion (42%) of the precipitation was conserved during the first fall and winter. Despite the fact that cumulative precipitation from spring to late fall during the fallow period averaged 243 mm, compared with 152 mm received during the previous fall and winter period, the amount (31 mm) and proportion (13%) of precipitation conserved was considerably less than that during the first overwinter period. These differences were attributed mainly to much higher summer evaporative losses. During the second overwinter period, only 6% of the precipitation received was conserved in the F-W (N + P) system compared with 44% in the first overwinter period. This poor conservation during the second winter was thought to be related to increased snow blowoff due to smaller amounts of standing crop residues, and to the freezing of a wet and bare soil surface, restricting water entry during snowmelt or spring thaw events. Physical based soil-crop models, which must be first improved for overwinter simulations, should be tested on the current data set to further interpret the observations and hypotheses. Compared with the 36% of fall and winter precipitation conserved in Cont W (N + P), inadequate N fertility [Cont W (+ P)] resulted in only 27% of the precipitation being conserved during this period. At harvest, F-W (N + P) and Cont W (N + P) had similar amounts of water in the soil, but Cont W (+ P) had significantly (P < 0.05) more because of reduced water use. However, by the following spring soil water recharge being proportional to crop residues produced resulted in F-W (N + P), Cont W (N + P) and Cont W (+ P) having 252, 209 and 204 mm/1.2 m soil, respectively. Equations were developed that will allow estimation of water conserved as a function of precipitation received between harvest and seeding for F-W (N + P) and Cont W (N + P) (R2 = 0.52*** in each case). Trends in grain yield were fairly closely correlated with growing season precipitation and potential evapotranspiration [squared semipartial correlation coefficients for Cont W (N + P) 0.32 and 0.17, respectively, and for F-W (N + P) 0.35 and 0.12]; soil water conservation played a minor role in determining final grain yields (squared semipartial correlation coefficient < 0.08). Key words: Soil water, spring wheat, precipitation deficit, yield trends, water conserved trends

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Long term (100 yr) climatic trends for agriculture at selected locations in Canada

Cited by 73 publications

References 18 publications

Trends of the thermal growing season in China, 1951–2007

Trends of the thermal growing season in China, 1951–2007

Variations of the climatological growing season (1951–2000) in Germany compared with other countries

Quantifying soil water conservation in the semiarid region of Saskatchewan, Canada: Effect of fallow frequency and N fertilizer

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