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Modern Sweet Cherry Production in Germany ( Moderner Süßkirschenanbau in Deutschland ) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Martin Balmer, Dienstleistungszentrum Ländlicher Raum – Rheinpfalz, Rheinbach, Germany. E-mail: Martin.Balmer@dlr.rlp.de Erstellt: 17.12.2012 Abstract The importance and the geographical extent of the German sweet cherry industry is described. Only the widespread introduction of dwarfing rootstocks, especially Gisela 5, has led to a successful increase of planting density on current 888-1388 trees / ha (single row). New tree forms are tested on a small scale. The standard assortment is dominated by 3 varieties: ‘Schneiders späte Knorpel’, ‘Kordia’ and ‘Regina’. Additionally, some new varieties are highlighted. The share of rain covering of total production area is small, but steadily increasing. Batches from raincovered plots are often marketed separately and have potential to get a higher price. Higher marketed quantities and a higher selling price must cover the very high investment. Rain shelter constructions have many side effects. One of these is the potential frost protection when covered at bloom. The introduction of mechanical grading is currently leading to major changes in the post-harvest sector. It is often accompanied by new storage and packaging techniques. 1. Introduction With 81.7 million inhabitants and a gross domestic product (GDP) of € 2.6 trillion, Germany is Europe's largest economy and fourth largest in the world. There are 14 cities with more than 500,000 inhabitants Germany is a densely populated industrial nation, the share of agriculture in GDP is less than 1 percent. Politically, the country is organized federally, which means that there are 16 federal states with an extensive administrative autonomy, including agricultural administration. The climate is temperate and characterized by both maritime and continental influences. The average annual rainfall is 789 mm, but varies between 400 and 1200 mm depending on geographical location. Table 1: Commercial growing of tree fruit, Germany 2012
In 2007 about 11,454 agricultural holdings produced tree fruits on 47,913 hectares. There are also berry bushes with approximately 5,000 hectares and about 17,200 ha of strawberries (2011). The vast majority is producing for the fresh market. Processing fruit has only significance when harvest can be mechanized (because of the high wages), or if they are niche products, such as elderberry. The number of fruit farms fell sharply (-50%) in the past 10 years. The data of the current tree fruit survey will be published only in the coming weeks. For sweet cherries, a stable upward trend will continue. The largest contiguous areas of fruit production are located along the Rhine river including the Lake Constance region and at the lower Elbe river near Hamburg in northern Germany. They are not always congruent with the centers of sweet cherry production. This are traditionally low-precipitation areas and the places where wine is grown, for exemple in southwestern Germany or in the rain shadow of the low mountain ranges in eastern Germany. Meanwhile, a growing sweet cherry production can be observed even in more humid regions of northern Germany, but there very often in combination with a rain protection.
Figure 1: Locations of Sweet Cherry Production in Germany (2007) In recent years, the german sweet cherry industry has developed positively caused by a good demand, good quality due to short transport distances, new dwarfing rootstocks, new varieties with high quality cherries. 2. Rootstocks and varieties 2.1. Rootstocks: The beginnings of a modern sweet cherry production in Germany about 25 years ago were made with planting densities of over 1000 trees per ha in the spindle training. At that time dwarfing rootstocks were scarcely available, and it was very problematic to work with vigorous rootstocks (lack of yield efficiency, control of tree vigor). In parallel to this development new dwarfing rootstocks, especially from the two breeding programs of Gießen and Weihenstephan, were tested intensively in experimental orchards. Meanwhile, Gisela 5 is the most important cherry rootstock and has a share of over 80% in new plantings since about 10 years. Under german conditions it can be characterized as follows: Gisela 5 ® (P. cerasus 'Schattenmorelle' x P. canescens) Advantages • 50-60% growth reduction in comparison to mazzard • Good precocity, high yield efficiency, good fruit size • Good compatibility and ancreage • Tolerant to replanting diseases under german conditions Disadvantages: • In poor soils supplementary irrigation is necessary • Additional work for rejuvenation of fruiting wood • Tendency to senescence under stress conditions (heat, drought) Especially the tree health, the high yields and its suitability for replanted land makes this rootstock interesting. It is developing well in countries of temperate climate while it has drawbacks in the hot climate of southern Europe and in very poor and sandy soils, such as in Poland. Other rootstocks being represented in new german orchards: Gisela 3, 20-30% weaker than Gisela 5, especially in systems with rain cover constructions. Weiroot 720 in the growth scale of Gisela 3 on an experimental basis. Piku 1 or Gisela 6 on poor and sandy soils or in combination with highly productive varieties. 2.2. Varieties: In addition to the susceptibility to rain cracking, in a global comparison the problems of sweet cherries are the low average yields and the high variation of the yield level. Due to climate change also traditional dry areas are no longer safe for heavy rainfall at the ripening time leading to cracking and rotting. Table 2: Effects on cherry production in Germany
Therefore the following requirements on varieties are resulting: High productivity and regular yields High picking rate High yield of marketable quality (especially low cracking and rotting, color harmony, few small sizes, etc.) Good firmness, at least 26 mm in diameter with a significant proportion of >28 mm Long harvest period of each cultivar Good technical product characteristics (sorting, transportation, storage, suitability for small packages) Table 3: Recommendation of sweet cherry varieties in 2012 for Rhineland-Palatinate
The main varieties are in bold. The two new early cherries ‘Bellise’ and ‘Samba’ are main varieties since 2008 and have proven themselves with the exception of regions where Pseudomonas is a threat. Among the varieties of the 4th week, ‘Satin’ and ‘Grace Star’ are recommended for experimental cultivation. They have to replace ‘Starking Hardy Giant’. ‘Carmen’ is only recommended for rain protected cultivation because of its high susceptibility to cracking. ’Grace Star’ is an easy cropper, but it is highly susceptible to Pseudomonas and therefore only suitable for dry climates. The fruit is medium firm, it has a medium susceptibility to bursting and a good fruit size only under vigorous growth conditions (soil, water supply, rootstock). ’Satin’ is currently one of the most interesting innovations. Reasons: Very large harvest period (2 weeks) until the maturity of ‘Kordia’, good cracking resistance, good size and fruit firmness. The taste is only average. In the first years this variety has to be pruned carefully, but after the first full yield a regular heavy pruning of the fruiting wood is necessary. It is inter-sterile with the cultivars ‘Samba’, ‘Masdel’, ‘Regina’, ‘Octavia’, ‘Sumbigo’, ‘Van’ (all S1S3). ’Schneiders späte Knorpel’ is an old variety that has still good prospects for the future and which is successfully marketed and cultivated in Europe under different names (‘Ziraat 0900’, ‘Germersdorfer’, ‘Ferrovia’, ‘Belge’, … The interest in new varieties should not distract from the two standard varieties ‘Kordia’ and ‘Regina’ which have strongly influenced the german sweet cherry industry over the the past 25 years. Both are late ripening with little susceptibility to cracking, large, firm and tasty. Their positive development would not have been possible without the combination with dwarfing and productive rootstocks. Even today they are among the most important varieties in new plantings. 3. Planting systems and tree training In Germany agricultural land becomes increasingly scarce for fruit growers due to urban sprawl and cultivation of energy plants. Also the comparatively high labor costs require a high intensity in orchard management. Due to the geographic location of the country between latitude 47° and 55° the planting density, however, has its limits. The standard planting system in Germany is in the single row combined with spindle training (Fig. 2). The optimal tree height is calculated using the formula of Winter (1981): Optimal Tree height = (row distance / 2) + 1 m In combination with Gisela 5 rootstock the row distances are ranging usually between 4.0 m and 4.50 m, the distances in the row between 1.80 m and 2.50 m. One important reason for early return of the orchard and low effort for tree training is the use of good planting material. In Germany this is the knip-tree (one-year old crown with anticipators on two year old rootstock) or the well-branched tree of one year (Fig. 3). With many different training methods the grower is able to obtain the optimum number of shoots with a good position and vigour. The more closely he has planted the more consistently he has to remove too strong side shoots. In so doing he is regarding the rules of Zahn (1986) concerning the ratio of the side branch vigour in relation to the leader. For being able to grow economically sweet cherries in the future, production costs have to be reduced still more. Actually we must calculate 60-80 hours per hectare for pruning and about 800 hours per hectare for manual harvesting (Balmer et al., 2010). Thinning is getting more important at dwarfing rootstocks, sometimes it is carried out manually. A new planting system should include the characteristics as follows: · Establishment of a new orchard should be payable (future of rainshelter (?), tree density, associated farm equipment). · Partial mechanization should be envisaged: mechanical bloom thinning, hedging, even mechanical harvest (Whiting, 2008). · Better utilization of the growth habit typical for the variety (‘Lapins’ in contrast to ‘Kordia’) · For hand picking a tree height below 3.0 m Some newer training forms are therefore now being tested in experimental farms plants and a few private orchards. Examples: Güttinger V-spindle, wide spindle for permanent roofing, flat canopy, UFO, Mur fruitier, etc..
4. Rain shelter Since both the producer and the marketer are interested to offer a predictable quality and quantity stone fruit growers who especially can suffer from the rigors of the weather are thinking more and more at a rain covering with greenhouse films. In this system the trees are not permanently standing in a foil greenhouse. They are covered only in the last phase of ripening when the fruit is prone to cracking and rotting. The sides are open (Fig. 4). In fact, the actual covered area for cherries is still low. Of the estimated 3,000 hectares of fresh market cherries in Germany, only 200 hectares are covered, but with a strong upward trend. The still limited distribution of rain covering primarly is due to the high investment costs. They are at least twice as high as the hail-net construction for an apple orchard because the higher susceptibility to wind and a greater ridge height need a greater material input. The creation of a covered sweet cherry orchard today requires an investment of € 80,000-100,000 per hectare (trees, roof, irrigation, labor). Only the expectation of a correspondingly higher revenue per hectare (higher prices per kg, more marketable quantity, regular yields, better quality ...) and a good economic situation of the company should lead to an investment decision. Over the past 10 years in practice and in experimental farms more and more results on the effect of a rain shelter on the fruit quality were obtained. They are listed in table 4: Table 4: Effect of rain covering on sweet cherries (Balmer, 2009)
Impact of cover: - unfavorable + high + + very high As shown in table 4, a rain cover can also cause disadvantages (besides the high investment). An example is the covering at frost (Fig. 5). While there is an effect against blossom frosts, covering during bloom means also more effort in insect pollination. Because the film remains mostly over the trees after bloom (otherwise then 100 hours of extra work), the trees grow more strongly induced by light deprivation, and growth regulation such as root cutting and summer pruning is getting more necessary.
5. Postharvest In Germany sweet cherries were always sorted on simple tables for quality but not on size. However, cherry exporting countries are using already for many years mechanized grading lines. At the sorting process, cherries in these countries often are transported in water to which chlorine is added or a fungicide. Only with the advent of large quantities of domestic production on the market advanced sorting technology was introduced in Germany. Meanwhile, almost all wholesale markets and coops dealing with sweet cherries have an optical sorting system or cooperate with private operations that provide a plant (Fig.6). At the grading lines with a capacity of >1 ton per hour in Germany there are currently 6 units that operate on the principle of optical sizing and 1 plant with mechanical sizing. However, since a very big part of German fresh market cherries is not sold through wholesalers, smaller lines are of great importance. Here the company Siegwald dominates the market that sells at a price starting from € 14,000 machines with a capacity of at least 200 kg / hour. Since post-harvest fungicides in Germany are not possible, we try as possible sorting without water. Where water is used, i.e. for the stalk separators, frequent changes of water cooling is inevitable. The use of MAP films is now in use. The additional costs for graded cherries are between 0.12 and 0.70 € / kg depending on the technique, daily duration of use and quality at picking. This requires appropriate additional revenues. This is possible because the cherries are payed according to size classes. It has been shown that the sorting costs are only covered, but we cannot expect more profit. To reduce costs, the capacity utilization of the machines should be expanded as possible by contract sorting and the use of other fruits such as plums, gooseberries, hazelnuts.
The storage of up to 1 week takes place in normal cooling cells. Long-term storage, which is met only seldom is practiced up to 6 weeks and only for durable late varieties. At a storage temperature of 1 ° C often film caps are used increasing air humidity to 100% and CO2 levels to values of 18-20% (Fig. 7). 6. Outlook Increasing yields, high costs of rain shelter and especially the wide introduction of mechanical sizing currently are leading to a change in philosophy for the variety choice. By grading it is now possible to skim off a premium segment from a variety with only a medium average fruit size but having high and constant yields. This variety is particularly interesting when it is characterized by a good tolerance to splitting. Constructions for rain cover will continue to evolve, but only up to a propertion of 10% (currently about 5%). Its primary function is the security for being able to market cherries in years with extreme rainfall and to win and retain customers. A really good variety that meets all requirements is at best the late 'Regina', but there is a need to catch up for the other ripening periods, especially in the early range. For years trials are made to thin out flowers or young fruits. The results are sometimes contradictory and the risk to get an additional yield loss is much greater than in pome fruit. Here too, sizing helps to some extent. Otherwise, only intensive culture techniques as pruning, fertilization and irrigation help to promote uniform yields and good sizes. At the rootstocks, Gisela 5 will probably remain the standard. More dwarfing rootstocks can be recommended only for best locations. Else they may cause early senescence of the orchard and there is always a danger of overcropping. Also in Germany, the cherry will continue to be a culture of risk and should be grown on a fruit farm only in combination with at least 2 other major crops. References Balmer, M. 2009. Der geschützte Steinobstanbau entwickelt sich. Besseres Obst 54: 12-15. Balmer, M., Baumann, W., Beer, M., Burmann, R., Eckhard, F., Fricke, K., Görgens, M., Keller, T., Kunde, S., Nörthemann, R., Uhte, R. 2010. VI Planungsbeispiele. In: KTBL-Datensammlung Obstbau. Kuratorium für Technik und Bauwesen in der Landwirtschaft. Darmstadt. 268 pages. Whiting, M.D. 2008. Süßkirschen mit verbesserter Produktionstechnik – neue Wege in den USA. Tagungsband 34. Bundesseminar Steinobst Ahrweiler, pp. 85-89. Winter, F. 1981. Anbausysteme. In: Lucas’ Anleitung zum Obstbau (Winter et al., eds.). Verlag Eugen Ulmer, Stuttgart, pp. 175-197. Zahn, F.-G. 1986. Intensivierung von Steinobstanlagen durch stärkenbezogene Schnittbehandlung. Erwerbsobstbau 28: 124-140. |
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