Simply put, the temperature sum represents accumulated heat energy over a period of time. Heat is one of the most important factors in the plant and animal world. Considering the fact that the heat can not be measured, while the temperature can, a model of effective temperature sums has been developed.<\/p>\n\n\n\n
The accumulated air temperature over a period of time determines the growth and development of plants. To use the daily temperature for determination of phenophases, it was necessary to develop a model of effective temperature sums. According to the definition, temperature sums or degree days are a measurement that reflects on the accumulated heat above a specific temperature threshold in a particular period: day, month, in the warm or cold part of the year, from one to another developmental phase of a plant. The temperature sum is calculated by taking away the threshold from the average daily temperature – if we determine that the temperature threshold is 10 \u00baC and the average temperatures in 5 days were: 12, 14, 9, 11, 15 \u00baC, this would mean that the effective temperatures were 2, 4, 0, 1, 5 \u00baC and that the sum of the effective temperatures for that period was 12 \u00baC. Base temperature is determined based on the need, as in determining the maturation of grapevine, a biological minimum of 10 \u00baC is taken.<\/p>\n\n\n\n
Temperatures in agriculture can be used for different purposes:<\/p>\n\n\n\n
Studies in the Netherlands and in England have shown that the optimal time for the application of nitrogen fertilizers to cereals is when the temperature sum is between 200 \u00baC and 300 \u00baC. The base temperature is set to 0 \u00baC and the values below 0 \u00baC are ignored. If the fertilizer is applied before the sum of temperatures reaches 200 \u00baC the results are not optimal.<\/p>\n\n\n\n
When choosing a planting site, it is necessary to have information on the microclimate as well as the accumulated effective temperatures throughout the vegetation season. It is also important to know what the sum of the effective temperatures is for the blossoming and ripening of the fruits of a particular crop and variety.<\/p>\n\n\n\n
When we compare these two data we find out easily whether the crop or variety suits the microclimate of the site. Apart from the temperature data, rainfall, winds, insolation, soil, groundwater, frequency of spring frost and other factors are as well considered key data. At locations where there is a greater risk of spring frost, it is preferable to choose crops or varieties that begin to blossom later, to reduce the risk of freezing.<\/p>\n\n\n\n
One of the limiting climatic factors for grape growing is temperature or in other words, heat. It is common that the average annual temperature is taken as an indicator, but from the wine growing aspect, it has been proved as insufficient. The sum of effective temperatures with a biological minimum (temperature threshold) of 10 \u00baC has shown as the best replacement for average temperature. The vegetation period for grapevine lasts from the beginning of April to the end of October. According to Winkler (1974), all vineyards in the world are divided into 5 climatic zones based on effective temperatures (table below).<\/p>\n\n\n\n The autochthonous varieties of some parts of the world are successfully grown in other areas as long as they are in the same climatic vineyard zone. As an example is the introduction of famous varieties (Grenache, Carignan, Syrah and others) of the Provance (France) wine-growing region to Ravne kotare near Zadar.<\/p>\n\n\n\n Breakdown by the sum of effective temperatures is particularly suitable for the selection of variety for a planting site\/region. Specifically, grapevine varieties differ distinctly by the time of maturity, which is caused by their internal\/genetic variability. Pulliat (1897) took into account the sum of the effective temperatures and divided the varieties according to the time of maturation in 5 groups:<\/p>\n\n\n\n Early varieties mature at a lower sum of effective temperatures and are suitable for growing in climatic zones with lower summers of effective temperatures (Chardonnay varieties in the region of West continental Croatia), while the late ones require much more heat for maturation and can only reach its optimum in regions with a higher amount of effective temperatures (Plavac mali red variety in the region of Primorje Croatia).<\/p>\n\n\n\n * [Temperature threshold 10 \u00baC, calculation starts on 01.03.]<\/p>\n\n\n\n As we have seen that heat influences the development of plants, it also affects the developmental cycle of plant pathogens and pests. Temperature sums are used to determine the maturity of oospores in grape vines. It is considered that oospores are mature when the sum is 160 to 170 \u00baC since the beginning of the calendar year with the temperature threshold of 8 \u00baC.<\/p>\n\n\n\n A study that was carried out in Turkey used temperature sums for determining the presence of grapevine moth. The results have shown that the first generation appeared around the accumulated 120 \u00baC, the second generation around 520 \u00baC and the third generation around 1047 \u00baC.<\/p>\n\n\n\n Pinova Meteo station with the help of your computer and a mobile app has an option to calculate the temperature sums. For more, click on PinovaMobile and PinovaSoft.<\/p>\n\n\n\n Tomislav Dvorski mag. ing. agr<\/strong><\/p>\n\n\n\n 1. Historical and recent viticulture as a source of climatological knowledge in the czech republic (2008) R. BR\u00a1ZDIL i sur. <\/p>\n\n\n\n 2. Ekologija u slu\u017ebi vinogradarstva (1997). N. Fazini\u0107, Melita Fazini\u0107<\/p>\n\n\n\n 3. Phenology and growing degree days, Mark Keller, Washington State University<\/p>\n","protected":false},"excerpt":{"rendered":" Simply put, the temperature sum represents accumulated heat energy over a period of time. Heat is one of the most important factors in the plant and animal world. Considering the fact that the heat can not be measured, while the temperature can, a model of effective temperature sums has been developed. The accumulated air temperature […]<\/p>\n","protected":false},"author":4,"featured_media":2458,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_et_pb_use_builder":"off","_et_pb_old_content":"","_et_gb_content_width":"","footnotes":""},"categories":[71],"tags":[],"class_list":["post-2542","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog"],"yoast_head":"\nClimatic zone<\/strong><\/td> Effective temperature sum<\/strong><\/td> Wine growing regions in the world<\/strong><\/td> Wine growing (sub)regions in Croatia<\/strong><\/td><\/tr> I<\/strong><\/td> < 1371 \u00baC<\/td> Tasmania, Champagne, Burgundy Friuli, Chablis<\/td> Moslavina, Prigorje-Bilogora Ple\u0161ivica, Pokuplje i Zagorje-Me\u0111imurje<\/td><\/tr> II<\/strong><\/td> 1372 \u2013 1648 \u00baC<\/td> Yarra Valley, Alsace, Boredeaux, Napa<\/td> Slavonija i Podunavlje<\/td><\/tr> III<\/strong><\/td> 1649 \u2013 1926 \u00baC<\/td> Rioja, Piemonte, Clare Valley, Capetown, Barossa valley<\/td> Part of North Dalmatia and subregion Dalmatinska zagora<\/td><\/tr> IV<\/strong><\/td> 1927 \u2013 2204 \u00baC<\/td> Langhore Creek, Montpellier, Florence, McLaren Vale, Provance<\/td> Istra, Croatian Littoral and a part of subregion of North Dalmatia<\/td><\/tr> V<\/strong><\/td> >2205 \u00baC<\/td> Sicily, Sardinia, Jerez, Swan Valley<\/td> Central and South Dalmatia \u2013 coastal island part<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n \n
Type<\/strong><\/td> Buds opening<\/strong><\/td> Blooming<\/strong><\/td><\/tr> Chardonnay<\/strong><\/td> \u0334 75 \u00baC<\/td> \u0334 345 \u00baC<\/td><\/tr> Cabernet Sauvignon<\/strong><\/td> \u0334 87 \u00baC<\/td> \u0334 375 \u00baC<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n Plant diseases and pests<\/h6>\n\n\n\n
References:<\/h6>\n\n\n\n