LW-R-2 + 3: Cultivating thermophilic crops and adapting variety spectrum
2023 Monitoring Report on the German Strategy for Adaptation to Climate Change
Table of Contents
LW-R-2: Cultivation and production of thermophilic arable crops
Durum wheat, soy and sorghum are thermophilic crops for which growing conditions have improved in Germany thanks to climate change. The interest in these crops is increasing to the same degree as breeders’ efforts to develop suitable varieties, and the extent of terrain on which seed material is produced is increasing too. In respect of soy, the development is proceeding in a particularly dynamic way, as the demand for soy has been rising vigorously.
The illustration contains a biaxial chart. The chart illustrates, by means of lines for 1991 to 2021, the number of the varieties – of summer durum wheat, winter durum, soybeans and sorghum – certified. In recent years, the number of certified varieties in respect of all crops has risen – significantly so – in respect of soybeans and summer durum. In 2021, just under 25 soybean varieties were certified for use in Germany. By means of stacked columns, the chart indicates the extent of the production terrain used for summer durum, winter durum and soybeans in hectares from 1991 to 2021. In respect of winter durum and soy, the production terrain increased significantly to roughly 1,000 and 1,500 hectares respectively. The production terrain for summer durum fluctuates around a consistent level.
LW-R-3: Adaptation of the variety spectrum in viticulture
Increasing amounts of warmth signify that even particularly thermophilic red grape varieties become suitable for cultivation in German cultivation areas. Although the cultivation terrain used for growing the internationally popular red grape varieties of Merlot and Cabernet Sauvignon is still limited, there are indications in wine statistics that it is in the process of expanding significantly.
The illustration contains a biaxial chart. The chart shows the percentual deviation of the Huglin Index for the period 1970 to 2021 from the multi-annual mean for the period 1961 to 1990. The time series shows a significantly rising trend, albeit with distinct fluctuations from year to year. The stacked columns illustrate the vineyard area cultivated with the grape varieties Merlot and Cabernet Sauvignon in hectares from 2002 and 2021. The total of this cultivated terrain has increased to roughly 1,300 hectares in 2021, thus demonstrating a significantly rising trend. 800 hectares of this terrain are cultivated for the Merlot grape variety.
Changed climate – new crops and varieties
Climate change and milder weather patterns open up new options for agriculture regarding the choice of crop species. The cultivation of thermophilic crop species in Germany may benefit from expansion provided there is sufficient market demand and the prospect of cultivation appeals to agricultural businesses from a commercial point of view. Thermophilic crop species include grain maize, sorghum, soybean, sunflowers and durum wheat. The increasing interest in thermophilic crop species is reflected not only in the cultivation terrain (cf. Indicator LW-R-4), but also in the activities undertaken in respect of the breeding of plant varietiesand seed production. This has led to an increase in demand for varieties which – in the current and prospective change in circumstances – promise high-quality crops and secure yields. Weather patterns – to the same extent as any prospective marketing opportunities, individual experience and preferences prevailing in agricultural businesses, their willingness to experiment, as well as other factors – play an important role in selecting a crop species. Breeders organise the development of their varieties in line with the new requirements. Nevertheless, it typically takes several years to breed a new variety and to obtain certification from the Federal Plant Variety Office (BSA). This means that changed demands for certain varieties is not always reflected in the number of new certifications. An important indication of the rising demand for seed material and mounting interest in growing certain crops is also reflected in the development of the terrain used for the production of seed material.
Especially over the past seven years, a clear dynamic was observed in the certification and production of seed material in respect of durum wheat and soy. As far as durum wheat is concerned, there is a distinct preference for winter durum wheat, as outwintering offers many cultivation advantages over spring sowing. With regard to soy, the cultivation of this crop species was given a commercial fillip in 2013 in view of grants becoming available within the BMEL’s protein plantstrategy111. Furthermore, discussions around a vegetarian or less meat-based diet have contributed to driving the development of suitable varieties forward, so that indigenous soy (also non-genetically modified) can be grown in the prevailing climatic circumstances. The first sorghum varieties were certified in 2017.
In deciding on annual crop varieties, agricultural businesses can be relatively flexible. However, with regard to perennial crops they have to make a long-term commitment when deciding on a specific variety. Especially in viticulture, the decision on new crop varieties to be planted requires careful deliberation, because vines have a long lifespan of up to 20 or 30 years. Besides, wine happens to be an agricultural product with extraordinarily high added value. The choice of variety is therefore particularly important.
For assessing the cultivation potential of specific grape varieties in certain wine-growing regions, the so-called Huglin Index is used. It sums up the days with temperatures of more than 10 °C for the period of 1st April to 30th September and indicates whether the amounts of warmth required by a grape variety for successful cultivation over an extended period can be achieved in a particular region. In the course of the past fifty years the Huglin Index has risen significantly throughout Germany. As a result, some highly thermophilic red grape varieties, hitherto limited to cultivation in southern regions, have now also become suitable for cultivation in German growing regions. Such varieties include Merlot, Cabernet Sauvignon and Syrah (also Shiraz). These grape varieties are highly acclaimed internationally which makes some viticulture businesses very keen on their cultivation subject to suitable climatic conditions. The areas where Merlot and Cabernet Sauvignon are cultivated, as recorded by wine statistics since 2002, are still comparatively small – in 2021 their proportion of viticultural terrain amounted to just short of 4 %. However, the recent increase in the terrain dedicated to growing these varieties indicates mounting interest. According to statistics, the grape variety Syrah quadrupled its growing terrain by 2021. It is to be expected that climate change will in future be reflected in the choice of grape varieties in Germany. However, it should be borne in mind that, especially in viticulture, consumer demand and fashion trends have a strong influence on decisions made by vintners on which grape varieties to cultivate.
Red grape varieties benefit greatly from climate change. As far as the cultivation of white grape varieties is concerned, climatic changes are seen more critically in respect of their impacts on wine quality and storage potential. Very high temperatures tend to produce rather disharmonious wines with high alcohol content and low acidity values. Nevertheless, this has so far not influenced the size of cultivation terrain used for white grape varieties in Germany.
111 - Informationen des BMEL zur Eiweißpflanzenstrategie: https://www.bmel.de/DE/themen/landwirtschaft/pflanzenbau/ackerbau/eiweisspflanzenstrategie.html.
