Ecological Conditions for Apple Cultivation
Understanding how the yield and profitability of apple production depend on the ecological conditions in which it is cultivated makes it clear why it is crucial to have a thorough understanding of the environmental factors of the intended growing area. The selection of planting material and the planting process itself are vital aspects when planning an orchard.
The apple has a wide geographical distribution because it can adapt to various ecological conditions. It is better adapted to moderate cold than extreme heat. It is considered that apples can be grown in a temperature range from 45 to -45 °C, but they thrive best at temperatures ranging from 35 to -25 °C. Most apple varieties prefer a moderate continental climate with an average annual temperature between 8 and 12 °C.
From among deciduous fruit species, apples have relatively low heat requirements but higher water needs. In regions where apples are grown and rainfall is insufficient, irrigation becomes necessary. The minimum amount of water required for apples is 600 mm at a temperature of 14 °C, 700 mm at 17 °C, and 1,060 mm at 20 °C. Apples require the most moisture from May to September.
Apple does not tolerate winds during flowering and fruit ripening, especially if they are dry and cold. The most favorable relative humidity for apple growth is around 75%.
The soil on which apples are grown must be sufficiently deep and permeable, have a good water-air ratio, contain more than 3% humus and be slightly acidic with a pH value of 5.5 to 6.5. Loamy soils are best, while apples can also be grown on clay soils, but only if the clay soil is sufficiently permeable. If the apple is grown on sandy soil, it must be intensively fertilized and irrigated. On alkaline soils, apples suffer from chlorosis.
Selection of apple planting material
The most refined and responsible professional part of the job when raising apple orchards is the selection and securing of planting material of certain varieties on the appropriate substrate. Everything that is planned and wanted in the plantation is ensured by fruit seedlings.
One- or two-year-old Knipp seedlings are recommended, with a well-developed root system and aerial part, which have become the standard for the apple. It is recommended to buy planting material from verified nurseries that have quality and labeled goods.
A selection of apple varieties
Correct variety selection is a basic prerequisite for successful production. When it comes to ecological conditions, its needs must be taken into account when choosing a variety. There are varieties that adapt very well to given environmental conditions, but do not always produce good quality fruits.
For example, the Golden Delicious variety produces the best fruit quality if it is grown in vineyard areas.
When choosing a variety, it is important to know that the apple is an extremely cross-fertilizing species, which means that monovarietal (one variety) plantations should not be raised due to prevented fertilization, which would result in sterility. So, to raise plantations, you should plan at least two varieties, if none of them is triploid, because triploid varieties cannot be pollinators due to the impossibility of pollen germination (eg Jonagold). So, in the case of a triploid variety, you should have at least two other different varieties that are sexually compatible with each other, i.e. that they can pollinate each other, in order for fertilization to occur.
In addition to the above, the composition of varieties should be combined with regard to market value and demand, high nature and labor productivity in implementing the complex technology of raising apple orchards.
More than 10,000 apple varieties have been created in the world today. Some data speak of 20,000. Considering such a large number, the choice of suitable varieties is not easy and should be given a lot of attention, because the mistakes made later are economically harmful in many ways.
The Croatian assortment of apples is reduced to a small number of varieties, of which the Idared variety takes the first place, followed by the Golden Delicious and, at best, clone B. In addition to those two varieties, Jonagold and its mutants, Granny Smith, are grown to a lesser extent and are gradually began to introduce mutants of the Gala variety group. Other varieties are rare. There are several reasons for this state of affairs. One of them is that our nurseries do not have mother trees of new high-quality varieties because they are all under the EU patent, so they may not be propagated and put on sale. A few years ago, the import of new varieties that were not on the so-called “variety list”. The variety list has been discontinued, so the import of newer varieties is enabled. Also, the time has come for our nurseries to start introducing the latest technology for the production of seedlings and new varieties in accordance with EU regulations in order to free themselves from importing seedlings from other countries, especially from those that do not produce high-quality and healthy planting material. In developed fruit-growing countries, the list of varieties exists only for the purpose of recommending to producers new better varieties for individual areas in relation to their ecological conditions. Thus there is a variety list for the continental area, for the coastal area, etc. Within these variety lists, list A, list B and list C are distinguished. consumer requirements), while in list C there is a suggestion of varieties for limited conditions or for local conditions. The proposal of the course is given by scientific and professional institutions. These lists are not binding because producers can grow the varieties they want, but they are recommended to grow better varieties, i.e. varieties with good biological and economic properties, because the fruits of such varieties will always find consumers on the market and achieve a better selling price.
Preparing the soil for apple planting
As the apple tree remains in the same place for up to 30 years after planting, full attention should be paid to the selection and preparation of the soil for cultivation.
Land preparation begins with clearing, cleaning and leveling the terrain. This is followed by meliorative fertilization and deep plowing. If the plantation is intended to be raised on terrain with a slope greater than 8 to 10%, then terraces must be made on the terrain beforehand. After that, it is necessary to improve the terrain. It is necessary that the soil contains a minimum of 3% humus. In order to increase the amount of humus by 1% at a depth of 40 cm, 20 t/ha of manure should be introduced into the soil. After the soil is fertilized with mineral and organic fertilizers, deep plowing follows to a depth of 50 to 70 cm. In fact, the depth of plowing depends on the type of soil, i.e. compacted soils are plowed deeper. Soil with better physical properties can be plowed to a depth of 40 to 50 cm. The most common time when the soil is plowed is in August and September, i.e. when the soil is moderately moist.
Apple planting
After the selected and prepared land, another very important part of agrotechnics follows, namely the selection of planting material and apple planting. It also consists of certain parts.
To begin with, it is very important to choose good and high-quality planting material. Besides the importance of knowing who to buy seedlings from, it is also very important to choose the right variety, because 50% of success in production is a well-chosen variety.
The next step is to choose a good substrate and decide on the best growing form. Next comes the selection of the optimal time and the creation of a planting plan, which includes determining and measuring the inter-row distance and the distance between trees within the rows, digging pits, choosing a cultivation system, preparing the seedlings and, finally, the planting technique itself.
Apple planting time
It is best to plant an apple in the dormant period of the vegetation, i.e. in autumn, winter or spring.
Preference is given to autumn planting, primarily because it is much easier to get quality planting material and the appropriate assortment during that period than in spring. An apple planted in autumn will have a greater growth, which will be decisive and will have a positive effect on the faster coming of the tree to fruiting.
Cultivation system and maintenance of apple orchards
Apple is a versatile fruit that can be grown on different substrates and in different climatic conditions. There are different apple growing systems for different growing conditions.
Apple growing system
As apple in intensive plantations is most often grafted on M 9 substrate and grown in the form of a slender spindle, the most common planting distance is 1.2 × 3.5 m, which means that two apple trees in a row are planted at a distance of 1.2 m, and that is the distance between the rows of 3.5 m, but the distances can vary from 0.8 m to 1.2 m between the trees, while the distance between the rows primarily depends on the agricultural machinery used in the orchard. That is why the set of plants can be from 2,500 to 5,000 seedlings/ha.
Flat ground is more suitable for growing apples because it allows easier access to agricultural machinery. In the case of gentler slopes, the distance between the rows should be slightly increased due to slipping of the machines during processing.
Maintenance of apple orchards
The soil in the apple orchard can be maintained as barren fallow, lawn or it can be grassed and mulched.
Most often, in modern, intensive orchards, the soil is maintained in the form of weeding the space between the rows, which must be mowed and mulched up to 8 times during the growing season, while herbicides are applied within the row between the trees to destroy all competing plants. Due to EU regulations, mechanical weed control in the row is increasingly encouraged.
